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Sample records for mustelus schmitti chondrichthyes

  1. Hifalomicose em Mustelus schmitti (Springer (Chondrichthyes, Triakidae Hyphalomycosis in Mustelus schmitii (Springer (Chondrichthyes, Triakidae

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    Manoel Mateus Bueno Gonzalez

    1999-06-01

    Full Text Available Both fungai and algal infections have been reported in elasmobranchs. This study describes the first record of hyphalomycosis infection in Mustelus schmitii (Springer, 1940. The data was obtained through the examination of one animal in captivity and ninety five in their natural environment. Was also detected four cases of Fusarium solani infection. The impact of these diseases on the wild population is unknown.

  2. The ovary of Mustelus schmitti (Chondrichthyes, Triakidae): microanatomy and development through the reproductive cycle

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    Galíndez, Elena Juana; Piscicelli, Juan Manuel; Wehitt, Anahí; Fuentes, Sabrina; Díaz Andrade, María Constanza; Estecondo, Silvia

    2010-01-01

    En este trabajo se describe la evolución estructural del ovario de Mustelus schmitti (gatuso) a lo largo del ciclo reproductivo. Se consideraron 3 estadios madurativos macroscópicos y se analizaron la población folicular en cada uno de e llos y la s características del estroma. En el ovario inmaduro (estadio I) sólo se encuentran los estadios iniciale s de la foliculogénesis. En los individuos juveniles (estadio II) empiezan a apreciarse signos de atresia folicular y en la madurez sexual (est...

  3. Histochemical study of the oviducal gland and analysis of the sperm storage tubules of Mustelus schmitti Springer, 1939 (Chondrichthyes, Triakidae

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    Fernanda Gabriela Elías

    2015-08-01

    Full Text Available Abstract: The paired oviducal glands of immature and mature females of Mustelus schmitti were examined macro and microscopically. Findings indicate that these glands possessed the same zonation as in most chondrichthyans from anterior to posterior: club, papillary, baffle and terminal zones. The whole gland is composed by simple tubular glands that connect with transverse grooves all along the organ. The club zone presents a typical indian club shape with a simple columnar and ciliated epithelium including secretory cells PAS (+ and AB (+. The papillary zone is characterized by lamella forming small and long cones in numbers of three. The epithelium of this zone contains ciliated cells with apical nuclei and secretory cells with basal nuclei that stain AB (+The baffle zone consists of apically flattened lamellae alternating with spinnerets which are small projections disposed by both sides of the plateau. This whole structure is present in number of 8 or 9 units. A simple columnar ciliated epithelium covers the plateau and spinnerets and no AB or PAS staining is observed. The epithelium of the terminal zone is PAS (- and AB (+, and elongated tubules, that run adjacent to the baffle zone are the site where groups of spermatozoa are clearly observed in the lumen. The epithelium of the sperm storage tubules do not stain with any of the dyes tested. Sperm was also observed in the baffle zone, presumably in its way to the fecundation in the oviduct because it displays no aggregation pattern and was between the folds of the epithelium. By scanning electron microscopy sperm was observed in the club and baffle zones in a gland which belonged to a pregnant female.

  4. Morphological indicators of initial reproductive commitment in Mustelus schmitti (Springer 1939 (Chondrichthyes, Triakidae: folliculogenesis and ovarian structure over the life cycle

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    EJ Galíndez

    Full Text Available This work provides information about the sexual commitment and the folliculogenesis of the gatuzo, Mustelus schmitti. A total of 112 females of all maturity stages were fished in the Bahía Blanca estuary, between 2009 and 2010. The oogonia were present throughout the life cycle of the animals. The folliculogenesis follows a pattern similar to other elasmobranchs. The granulosa layer keeps monolayered throughout the folliculogenesis, but with two cell types in the vitellogenic follicle. The zona pellucida forms in the primordial follicles. The thecal system shows a connective inner layer and a glandular outer sheath. The microscopic beginning of the sexual commitment, indicated by the vitello hoarding, takes place in follicles from 500 micrometres, while the macroscopic evidence appears in follicles of 2500-3000 micrometres. The results presented in this study suggest that the fishery pressure may affect a susceptible range of sizes of the species, not previously considered and provides a biological framework for the development of fisheries policy.

  5. Population structure, distribution and abundance patterns of the patagonian smoothhound Mustelus schmitti Springer, 1939 (Chondrichthyes, Elasmobranchii, Triakidae in the rio de La Plata and inner continental shelf , sw Atlantic ocean (34º30'-39º30'S

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    María Cristina Oddone

    2007-09-01

    Full Text Available A total number of 4824 Mustelus schmitti was sampled. Females ranged from 25 to 93 cm in spring and from 28 to 90 cm in summer. Males ranged from 34 to 82 and from 28 to 77 cm, respectively. Length composition of the population showed significant differences between spring and summer being females larger than males. Total length distribution did not show significant differences between cruises. Males density varied significantly between cruises while for the females no significant variation was observed. In the spring cruise, both sexes occurred at depths lower than 50 m. Females occurred in the whole area with adult occurrence only above 35°30'S. Mature males occurred throughout the area, immature males occurring in two trawls in Samborombón Bay. The summer cruise showed a discontinuous distribution of the species along the study area resulting in spatial segregation in two groups with immature females predominating in both of them.Um total de 4824 Mustelus schmitti foi amostrado. As fêmeas apresentaram comprimento total de 25-93 cm na primavera e 28-90 cm no verão enquanto os machos apresentaram 34-82 e de 28-77 cm, respectivamente. A composição de comprimentos da população mostrou diferenças significativas entre primavera e verão sendo as fêmeas maiores do que os machos. A distribuição de comprimento total não variou significativamente entre cruzeiros. A densidade variou significativamente entre cruzeiros nos machos sendo que a variação não foi expressiva nas fêmeas. No cruzeiro da primavera, ambos os sexos ocorreram em profundidades menores do que 50 m, as fêmeas ocorrendo em toda a área de estudo, as adultas somente acima da latitude 35°30'S. Os machos adultos foram observados em toda a área sendo que os imaturos somente em dois arrastos na Bahia de Samborombón. O cruzeiro de verão mostrou uma distribuição descontínua da espécie ao longo da área de estudo, resultando na segregação espacial em dois grupos, com

  6. Estimación de un índice de abundancia anual de gatuzo (Mustelus schmitti) a partir de datos de la flota comercial argentina. Período 1992-2008

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    Pérez, M.(Institute for Fundamental Theory, Department of Physics, University of Florida, Gainesville, FL, 32611, U.S.A.); Massa, A.M.; Cordo, H.D.

    2011-01-01

    Patagonian smoothhound (Mustelus schmitti) is one of the predominant cartilaginous fishes of the Argentine Sea (SW Atlantic Ocean). It is caught, mainly, in the coastal multispecific fishery with nearly other 30 bony and cartilaginous species. The group is known as ‘variado costero’. In this work the smoothhound abundance indices (CPUE) and standardized efforts for the 1992-2008 period in the area between 34~’S-42~’S were estimated. The General Lineal Model (GLM) and data derived from the arg...

  7. Catch and size selectivity of small-scale fishing gear for the smooth-hound shark Mustelus mustelus (Linnaeus, 1758 (Chondrichthyes: Triakidae from the Aegean Turkish coast

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    T. CEYHAN

    2010-10-01

    Full Text Available Catch rate, CPUE, biomass ratios and size selectivity from traditional longline and trammel nets of Turkish coastal small-scale fisheries were investigated in order to describe the Smooth-hound shark (Mustelus mustelus fishery. The SELECT method was used to estimate the selectivity parameters of a variety of models for the trammel nets inner panel of 150 and 170 mm mesh sizes. Catch composition and proportion of the species were significantly different in longline and trammel nets. While mean CPUE of longline was 119.2±14.3 kg/1000 hooks, these values for 150 and 170 mm trammel nets were 5.3±1.2 kg/1000 m of net and 12.7±3.9 kg/1000 m of net, respectively. Biomass ratios of the by catch to Smooth-hound catch were found to be 1:0.32 for 150 mm trammel net, 1:0.65 for longline and 1:0.73 for 170 mm trammel net. The estimated modal lengths and spreads were found to be 91.1 and 16.2 cm for 150 mm and 103.2 and 18.4 cm for 170 mm, respectively. The modal lengths of the species as well as the spread values increased with mesh size.

  8. Catch and size selectivity of small-scale fishing gear for the smooth-hound shark Mustelus mustelus (Linnaeus, 1758 (Chondrichthyes: Triakidae from the Aegean Turkish coast

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    T. CEYHAN

    2012-12-01

    Full Text Available Catch rate, CPUE, biomass ratios and size selectivity from traditional longline and trammel nets of Turkish coastal small-scale fisheries were investigated in order to describe the Smooth-hound shark (Mustelus mustelus fishery. The SELECT method was used to estimate the selectivity parameters of a variety of models for the trammel nets inner panel of 150 and 170 mm mesh sizes. Catch composition and proportion of the species were significantly different in longline and trammel nets. While mean CPUE of longline was 119.2±14.3 kg/1000 hooks, these values for 150 and 170 mm trammel nets were 5.3±1.2 kg/1000 m of net and 12.7±3.9 kg/1000 m of net, respectively. Biomass ratios of the by catch to Smooth-hound catch were found to be 1:0.32 for 150 mm trammel net, 1:0.65 for longline and 1:0.73 for 170 mm trammel net. The estimated modal lengths and spreads were found to be 91.1 and 16.2 cm for 150 mm and 103.2 and 18.4 cm for 170 mm, respectively. The modal lengths of the species as well as the spread values increased with mesh size.

  9. Reproductive biology and diet of Mustelus punctulatus (Risso, 1826 (Chondrichthyes: Triakidae from the Gulf of Gabès, central Mediterranean Sea

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    Bechir Saïdi

    2009-06-01

    Full Text Available Specimens of Mustelus punctulatus were collected between January 2002 and December 2005 from commercial fisheries in the Gulf of Gabès (central Mediterranean Sea. Males and females reached a maximum total length (TL of 111 and 122 cm respectively. Males matured between 76 and 88.5 cm TL, with a size at maturity (TL50 of 81.4 cm TL. Females matured between 88 and 100 cm TL with a TL50 of 95.6 cm. Females had an annual reproductive cycle. Mating occurred through late-May and June. Ovulation occurred from early July to mid-August with parturition occurring from mid-May to early June, after a gestation period of 11 months. The size at birth was estimated to be 24.5 to 30.5 cm TL. Positive linear relationships were detected between the TL of mature females and ovarian and uterine fecundities. Mustelus punctulatus is an opportunistic predator that consumes a wide range of demersal and benthic prey items. It preys mainly on crustaceans, teleosts and molluscs. Polychaetes, sipunculids, echinoderms and tunicates are also consumed. The species change their main food item as they grow, from crustaceans to teleosts then to molluscs.

  10. Trypanorhyncha from sharks of southern brazilian coast: Eutetrarhynchus vooremi sp. n. and two other species parasites of Mustelus (Pisces, Triakidae

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    Sergio Carmona de São Clemente

    1989-01-01

    Full Text Available In the present paper, Eutetrahynchus vooremi sp. n., a cestode of the order Trypanorhyncha is proposed. The new species was recovered from sharks under the genus Mustelus (Pisces, Triakidae and was compared to E. ruficollis, E. lineatus, E. leucomelanus, E. litocephalus and E. macrotrachelus. The main character, among others, considered to differ the species refers to the eggs filament, size of proglottids, tentacular hooks and lenght of pars postbulbosa. Two other known species are studied: Callitetrarhynchus gracilis (Rudolphi, 1819 from M. canis (Mitchill, 1815 and Nybelinia (N. lingualis (Cuvier, 1817 from M. schmitti Springer, 1939 representing new host records.

  11. The genus Mustelus Linck, 1790 (Family Triakidae, Order ...

    African Journals Online (AJOL)

    spamer

    Mustelus mustelus and. M. palumbes) off southern Africa ... between East London and Langabaan Lagoon (Fig. 1),. 230 ..... nutrients, possibly in the uterine fluid, that contributes to embryonic ..... to be dynamic and are likely to be related in part to.

  12. New molecular tools for the identification of 2 endangered smooth-hound sharks, Mustelus mustelus and Mustelus punctulatus.

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    Marino, Ilaria A M; Riginella, Emilio; Cariani, Alessia; Tinti, Fausto; Farrell, Edward D; Mazzoldi, Carlotta; Zane, Lorenzo

    2015-01-01

    The smooth-hounds represent a significant proportion of the elasmobranch catch in the Adriatic basin of the Mediterranean Sea, where the common (Mustelus mustelus) and blackspotted (Mustelus punctulatus) smooth-hounds co-occur. The 2 species share several morphological and morphometric characters that lead to frequent misidentification. In order to provide information useful for their species identification, we performed a morphological identification of several Mustelus specimens to select individuals unambiguously attributed to 1 of the 2 species, and assayed these with 3 new molecular tests. First, we developed and validated a mitochondrial DNA assay based on species-specific amplification of the cytochrome c oxidase subunit 1 (COI). Second, a fragment analysis of 15 microsatellites cross-amplified from several triakid species was performed to identify diagnostic loci. Finally, a length difference was identified in the internal transcribed spacer 2 (ITS2) region and a diagnostic test based on its amplification was established. All the samples classified morphologically as M. mustelus and M. punctulatus showed a species-specific profile using all the 3 molecular tests. In addition, cross-amplification of microsatellites allowed identification of 9 highly polymorphic loci that will be useful for the study of the mating system and population differentiation of the 2 species.

  13. Computer-assisted evaluation of isoelectric focusing patterns in electrophoretic gels: identification of smoothhounds (Mustelus mustelus, Mustelus asterias) and comparison with lower value shark species.

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    Renon, P; Colombo, M M; Colombo, F; Malandra, R; Biondi, P A

    2001-05-01

    In this work, the most commercially important Selachian species, smoothhound (Mustelus mustelus) and starry smoothhound (Mustelus asterias), have been identified by polyacrylamide isoelectric focusing (IEF-PAGE), along with several shark species of minor commercial value. In Italy, these two smoothhound species are commonly subjected to fraudulent substitution with lesser valued sharks. After the electrophoretic runs, the band patterns of the two Mustelus species were compared with those of dogfish (Scyliorhinus canicula), spurdog (Squalus acanthias), blue shark (Prionace glauca) and black-mouthed dogfish (Galeus melanostomus), both visually and with gel analysis software. The actual isoelectric points were then submitted to cluster analysis to differentiate the single species, despite the possible occurrence of electrophoretic variations or protein polymorphism. Every shark showed species-specific band patterns and could therefore be well differentiated, as confirmed by statistical analysis.

  14. Heavy metal accumulation and toxicity in smoothhound (Mustelus mustelus) shark from Langebaan Lagoon, South Africa.

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    Bosch, Adina C; O'Neill, Bernadette; Sigge, Gunnar O; Kerwath, Sven E; Hoffman, Louwrens C

    2016-01-01

    Together with several health benefits, fish meat could introduce toxins to consumers in the form of heavy metal contaminants. High levels of mercury (Hg), especially, are frequently detected in certain predatory fish species. Mustelus mustelus fillets were analysed for 16 metals and three individual Hg species (inorganic Hg, ehtylmercury, methylmercury) with inductively coupled plasma mass spectrometry (ICP-MS) and HPLC-ICP-MS respectively. Eleven of the 30 sharks had total Hg levels above the maximum allowable limit with toxic methylmercury found as the dominant mercury species with a strong correlation (r = 0.97; p mercury concentrations. Limited correlations between metals and shark size parameters were observed; therefore metal accumulation in M. mustelus is mostly independent of size/age. Average values for arsenic (28.31 ± 18.79 mg/kg) exceed regulatory maximum limits and Hg (0.96 ± 0.69 mg/kg) is close to the maximum limit with all other metals well below maximum limits.

  15. Antimodernistlik tegutseja modernismis : sissejuhatus Carl Schmitti riigifilosoofilisse õpetusse / Heimes. Claus ; tõlk. Peeter Helme

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    Heimes. Claus

    2004-01-01

    Saksa poliitilise teoreetiku, riigiõigusasjatundja ja kristliku filosoofi Carl Schmitti (1888-1985) seisukohtadest poliitilises teoloogias ja antropoloogias, uusajatõlgendusest ning positivistliku kaasaja kriitikast. Tõlke allikas: Antimoderner Akteur der Moderne : eine Einführung in die staatsphilosophische Lehre Carl Schmitts

  16. Antimodernistlik tegutseja modernismis : sissejuhatus Carl Schmitti riigifilosoofilisse õpetusse / Heimes. Claus ; tõlk. Peeter Helme

    Index Scriptorium Estoniae

    Heimes. Claus

    2004-01-01

    Saksa poliitilise teoreetiku, riigiõigusasjatundja ja kristliku filosoofi Carl Schmitti (1888-1985) seisukohtadest poliitilises teoloogias ja antropoloogias, uusajatõlgendusest ning positivistliku kaasaja kriitikast. Tõlke allikas: Antimoderner Akteur der Moderne : eine Einführung in die staatsphilosophische Lehre Carl Schmitts

  17. Molecular characterization of penaeidins from two Atlantic Brazilian shrimp species, Farfantepenaeus paulensis and Litopenaeus schmitti.

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    Barracco, Margherita Anna; de Lorgeril, Julien; Gueguen, Yannick; Bachère, Evelyne

    2005-09-01

    We report here the molecular cloning of new members of the penaeidin family from two Atlantic penaeids from Brazil, Litopenaeus schmitti and Farfantepenaeus paulensis. The presence of penaeidins in the granular hemocytes of both shrimps was first evidenced by immunofluorescence, using polyclonal antibodies raised against L. vannamei penaeidin Litvan PEN3-1. cDNAs from the hemocytes of both Brazilian species were obtained by reverse transcription and the sequences encoding penaeidins were amplified by PCR, using primers based on penaeidin consensus sequences. Five penaeidin clones were obtained. According to the international penaeidin classification (PenBase, http://www.penbase.immunaqua.com), the deduced amino acid sequences of two clones from L. schmitti and two from F. paulensis belong to the PEN2 subgroup and one clone from L. schmitti to the PEN4 subgroup of penaeidins. Surprisingly, no penaeidin from the PEN3 subgroup was obtained in both shrimp species, even though this subgroup appears to be the most commonly expressed in the hemocytes of penaeids.

  18. Dietas practicas para el cultivo de Litopenaeus schmitti: una revisión (Practical diets for Litopenaeus schmitti shrimp culture: a review

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    Jaime-Ceballos, Barbarito:

    2006-12-01

    Full Text Available Se resumen los resultados del trabajo desarrollado por investigadorescubanos en el campo de la alimentación y nutrición del camarónblanco Litopenaeus schmitti, referidos a la formulación de alimentosbalanceados para las fases de precría y engorde. Aporta información sobre la respuesta de dicha especie a la inclusión de materias primasconvencionales o no en dietas prácticas, constituyendo una vía deabaratamiento de las mismas mediante el uso de ingredientes nacionales. Además se muestran los resultados obtenidos en cuanto aempleo de aglutinantes, tamaños de partículas e investigaciones básicas aplicadas a esta actividad. Estos estudios han servido de base para la obtención de alimentos comerciales eficientes que sustentan el desarrollo de la camaronicultura en Cuba, propiciando el diseño de alimentos acordes a las necesidades y posibilidades del país, constituye un valioso material para el conocimiento y desarrollo del cultivo en cuanto a Results of the research workdeveloped by Cuban investigators on feeding and nutrition of white shrimp Litopenaeus schmitti, referred the food formulation for nursery and grow-out phases. It contributes information on the answer of this species to the inclusion of conventional raw materials or not in practical diets, constituting a via to reduce prices trough the use of national ingredients. In addition results obtained as far as use of aglutinantes, sizes of particles and basic investigations applied to this activity are shown. These studies have served as base to obtain efficient commercial diets that have supported the development of shrimp culture in Cuba, facilitating the designof artifitial food according to the necessities and possibilities of the country, constituting a valuable material for the knowledge anddevelopment of the culture as far as feeding and nutrition.H

  19. Population genetic structure of Brazilian shrimp species (Farfantepenaeus sp., F. brasiliensis, F. paulensis and Litopenaeus schmitti: Decapoda: Penaeidae

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    Jaqueline Gusmão

    2005-03-01

    Full Text Available Penaeid shrimps are important resources for worldwide fisheries and aquaculture. In the Southwest Atlantic, Farfantepenaeus brasiliensis, F. paulensis, F. subtilis, Farfantepenaeus sp. and Litopenaeus schmitti are among the most important commercially exploited species. Despite their high commercial value, there is little information available on the different aspects of their biology or genetics and almost no data on their stock structure. We used allozymes to estimate variability levels and population genetic structure of F. brasiliensis, F. paulensis, L. schmitti and the recently detected species Farfantepenaeus sp. along as much as 4,000 km of Brazilian coastline. No population heterogeneity was detected in F. brasiliensis or L. schmitti along the studied area. In contrast, F ST values found for Farfantepenaeus sp. and F. paulensis indicate that the populations of those two species are genetically structured, comprising different fishery stocks. The largest genetic differences in F. paulensis were found between Lagoa dos Patos (South and the two populations from Southeast Brazil. In Farfantepenaeus sp., significant differences were detected between the population from Recife and those from Fortaleza and Ilhéus.

  20. Use of oxygen consumption and ammonium excretion to evaluate the sublethal toxicity of cadmium and zinc on Litopenaeus schmitti (Burkenroad, 1936, Crustacea).

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    Barbieri, Edison

    2007-06-01

    Penaeid shrimps are important resources for worldwide fisheries and aquaculture. In Brazil, Litopenaeus schmitti (L. schmitti) is a important commercially exploited species and is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. The main purpose of the present study was to detect the acute toxicity of cadmium and zinc to L. schmitti and investigate their effects on oxygen consumption and ammonium excretion, investigations that have not been carried out in this species before. First, the acute toxicity of cadmium and zinc to L. schmitti 24, 48, 72, and 96-hour medium lethal concentration was examined, which resulted in the following values: 0.98, 0.54, 0.32, and 0.18 mg/L for cadmium and 1.64, 1.22, 0.86, and 0.31 mg/L for zinc. Furthermore, we also found that exposure of shrimp to cadmium and zinc caused an inhibition in oxygen consumption of 55.92 and 44.09%, respectively, relative to the control. However, after separate exposure to cadmium and zinc, elevations in ammonium excretion were obtained, which were 174.28 and 162.5% higher than the control, respectively.

  1. Ecological distribution and population structure of Acantholobulus schmitti (Rathbun, 1930 (Crustacea, Decapoda, Xanthoidea on the southeastern Brazilian coast

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    Vivian Fransozo

    2013-12-01

    Full Text Available This investigation analyzed the ecological distribution and population structure of A. schmitti on the southeastern coast of Brazil. Crabs were sampled monthly from January 1998 to December 1999 at the following bays: Ubatumirim (UBM, Ubatuba (UBA and Mar Virado (MV. Water and sediment samples were also collected from all sampling sites for an analysis of environmental factors. Acantholobus schmitti was most abundant at UBM (224, followed by UBA (154 and MV (23 but its abundance showed no association with the environmental factors analyzed. The low abundance of these crabs in MV may be due to the high wave action that moved biodetritic material accumulated on the bottom and frequently removed small crabs from their sheltered positions among the shell fragments. The individuals captured included 269 males and 132 females, of which only 4 specimens were brooding females. Juvenile recruitment occurred throughout the year, but was less intense in the spring. The major abundance of individuals as well as of ovigerous females occurred during 1999, when the entrance of the South Atlantic Central Waters (SACW was stronger than in previous year. This environmental influence could be the main factor modulating this population.

  2. Efecto de ensilados de pescado e hígado de tiburón en el crecimiento de Litopenaeus schmitti, en sustitución de la harina y el aceite de pescado(Effect of fish silage and liver of sharks in the growth of Litopenaeus schmitti in place of fish meal and fish oil

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    Fraga-Castro, Iliana E

    2011-11-01

    Full Text Available ResumenDos diseños experimentales completamente aleatorizado se desarrollaron durante 6 semanas, para evaluar el efecto de dietas con ensilados de pescado (EP e hígado de tiburón (EHT, en el crecimiento de juveniles de camarón blanco Litopenaeus schmitti (peso inicial 1.3 ± 0.12 g. El EP con desechos de tilapia se incluyó en las dietas a niveles de 0, 16.5, 27.5 y 31 %, en sustitución de la harina de pescado.AbstractIn order to evaluate the effect of diets with fish silage (EP and shark liver (EHT, the growth of juvenile white shrimp Litopenaeus schmitti (mean initial weight 1.3 ± 0.12, developed a laboratory scale two completely randomized design for 6 weeks.

  3. Requerimientos nutricionales de juveniles de camarón blanco (Litopenaeus schmitti): evaluación de dietas prácticas

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    Galindo, J; Fraga, I.; de Arazoza, M.; S. Alvarez; Ramos, D.; González, R.

    2002-01-01

    Con el objetivo de determinar el efecto de diferentes relaciones proteína/energía (P/E), sobre el crecimiento de juveniles de Camarón Blanco Litopenaeus schmitti , mediante la utilización de dietas prácticas, se desarrolló un diseño experimental completamente aleatorizado, a escala de laboratorio, durante 59 días. Se evaluaron 12 dietas con diferentes niveles de inclusión de proteínas, lípidos y carbohidratos. El crecimiento fue mayor en los camarones que se alimentaron con las...

  4. Nascimento da Raia-viola, Zapteryx brevirostris (Müller & Henle (Chondrichthyes, Rhinobatidae, em cativeiro Birth of guitarfish, Zapteryx brevirostris (Müller & Henle (Chondrichthyes, Rhinobatidae in captivity

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    Manoel M. B. Gonzalez

    2004-12-01

    Full Text Available Um exemplar fêmea de Zapteryx brevirostris foi capturada na Ilha Queimada Grande, Itanhaém, São Paulo em 19/II/2002, e transportada para o cativeiro do Núcleo de Pesquisa e Estudo em Chondrichthyes (NUPEC. Em 21/II/2002, a fêmea pariu seis filhotes (três machos e três fêmeas. Este é o primeiro registro de nascimento de Z. brevirostris em cativeiro.A female of Zapteryx brevirostris were caught at Queimada Grande Island, Itanhaém, São Paulo on 19/II/2002, and transported to Núcleo de Pesquisa e Estudo em Chondrichthyes (NUPEC captivities. At 21/II/2002, the female gave birth to six pups (three males and three females. This is a first birth record of Z. brevirostris in captivity.

  5. On the occurrence of the Bull Ray Pteromylaeus bovinus (Chondrichthyes: Myliobatidae in the Amvrakikos Gulf, Greece

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    S. ZOGARIS

    2012-12-01

    Full Text Available We document in this note the occurrence of the Bull Ray Pteromylaeus bovinus (Geoffroy St-Hilaire, 1817 (Chondrichthyes: Myliobatidae in the Amvrakikos Gulf (eastern Ionian Sea, within a recently designated Wetlands National Park. Although distributional data for this species are scant, there is circumstantial evidence depicting the species as rare in Greece and the Mediterranean.

  6. Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae) from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus (Carcharhiniformes, Triakidae) from off Tunisia

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    Boudaya Lobna; Neifar Lassad

    2016-01-01

    Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae, Merizocotylinae) is described from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus collected from the coastal marine waters off Tunisia. The new parasite species is distinguished from the other two species of the genus, T. japanicae Kearn, 1993 and T. chisholmae Justine, 2009, by the morphology of the sclerotised male copulatory organ which has longitudinal ridges. The species is also characterised by its oötype w...

  7. Hábitos alimentarios de Mustelus lunulatus y M. henlei (Pisces: Triakidae) colectados en el Parque Nacional Natural Gorgona, Pacífico colombiano

    OpenAIRE

    Gómez, G.O.; Zapata, L. A.; Franke A., R.; Ramos, G.E.

    2003-01-01

    From June 1988 to July 1992, non-continuous samples of two species of cartilaginous fish of the family Triakidae were taken in the National Natural Park Gorgona. Stomach contents of 139 individuals of Mustelus lunulatus and 51 individuals of M. henlei were analyzed. These species predate on crustaceans (93,06%), mainly Portunus iridiscens, Squilla panamensis and Hipoconcha panamensis, secondly on mollusks of the family Loliginidae (4,32%) and fishes (2,28%) in a smaller proportion; the remain...

  8. Reproductive characteristics and life-history relationships of starry smooth-hound Mustelus asterias in British waters.

    Science.gov (United States)

    McCully Phillips, S R; Ellis, J R

    2015-12-01

    The reproductive biology and other life-history parameters were investigated for Mustelus asterias in British waters, with specimens caught from both commercial fisheries and research-vessel surveys. In total, 504 specimens [238 males, 24-99 cm total length (LT) and 266 females, 28-124 cm LT] were examined, with further information collected from 238 uterine pups. The lengths at 50% maturity were estimated as 70·4 and 81·9 cm LT for males and females, respectively. Ovarian fecundity ranged from one to 28, and uterine fecundity from four to 20. The number, mass and LT of pups were positively correlated with maternal LT. Full-term pups ranged from 205 to 329 mm LT, and the smallest free-living fish caught was 24 cm LT . Parturition occurred in February in the western English Channel and during June to July in the eastern English Channel and southern North Sea, indicating either protracted spawning or asynchronous parturition for the stock as a whole. The reproductive cycle is thought to extend beyond 1 year. Developmental abnormalities observed included atresia in oocytes, uterine eggs that failed to develop, a partly developed pup and an abnormal male with a single aberrant clasper. Data relating to conversion factors, oocyte numbers and diameter and gonado-somatic and hepato-somatic indices are presented, and the seasonality of the reproductive cycle is discussed.

  9. The interleukin 1 (IL-1 system in the uteroplacental complex of a cartilaginous fish, the smoothhound shark, Mustelus canis

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    Hamlett William C

    2003-02-01

    Full Text Available Abstract Cartilaginous fish are the oldest extant jawed vertebrates and the oldest line to have placentae. Their pivotal evolutionary position makes them attractive models to investigate the mechanisms involved in the maternal-fetal interaction. This study describes the tissue expression of the cytokine interlukin-1 (IL-1 α, IL-1 β and its specific membrane receptor, IL-1 receptor type I (IL-1R tI in a placental cartilaginous fish, the smoothhound shark, Mustelus canis. The presence of this cytokine has been reported in many mammalian placentae, as well as in the placenta of a squamate reptile and this study extends these observations to the cartilaginous fishes. The uteroplacental complex in M. canis consists of a yolk sac modified into a functional yolk sac placenta and complimentary uterine attachment sites. Immunohistochemistry for IL-1 α, IL-1 β and the receptor reveals leucocytes of both the mother and fetus to be positive, as well as the apical aspect of paraplacental cells and the apical vesicles in the umbilical cord epithelium. Yolk sac endoderm is also positive with all the stains while the ectoderm is positive only for IL-1 α. Immunoreactivity in the uterine epithelium was obtained for IL-1 α and the receptor. The egg envelope is always negative. In light of the recent finding of IL-1 β gene in a cartilaginous fish and of the high level of conservation of proteins implicated in IL-1 action, our data suggest that IL-1 system is a key mediator of the materno-fetal interaction since the oldest extant placental vertebrates.

  10. Physiological responses to hypersalinity correspond to nursery ground usage in two inshore shark species (Mustelus antarcticus and Galeorhinus galeus).

    Science.gov (United States)

    Tunnah, Louise; MacKellar, Sara R C; Barnett, David A; MacCormack, Tyson J; Stehfest, Kilian M; Morash, Andrea J; Semmens, Jayson M; Currie, Suzanne

    2016-07-01

    Shark nurseries are susceptible to environmental fluctuations in salinity because of their shallow, coastal nature; however, the physiological impacts on resident elasmobranchs are largely unknown. Gummy sharks (Mustelus antarcticus) and school sharks (Galeorhinus galeus) use the same Tasmanian estuary as a nursery ground; however, each species has distinct distribution patterns that are coincident with changes in local environmental conditions, such as increases in salinity. We hypothesized that these differences were directly related to differential physiological tolerances to high salinity. To test this hypothesis, we exposed wild, juvenile school and gummy sharks to an environmentally relevant hypersaline (120% SW) event for 48 h. Metabolic rate decreased 20-35% in both species, and gill Na(+)/K(+)-ATPase activity was maintained in gummy sharks but decreased 37% in school sharks. We measured plasma ions (Na(+), K(+), Cl(-)) and osmolytes [urea and trimethylamine oxide (TMAO)], and observed a 33% increase in plasma Na(+) in gummy sharks with hyperosmotic exposure, while school sharks displayed a typical ureosmotic increase in plasma urea (∼20%). With elevated salinity, gill TMAO concentration increased by 42% in school sharks and by 30% in gummy sharks. Indicators of cellular stress (heat shock proteins HSP70, 90 and 110, and ubiquitin) significantly increased in gill and white muscle in both a species- and a tissue-specific manner. Overall, gummy sharks exhibited greater osmotic perturbation and ionic dysregulation and a larger cellular stress response compared with school sharks. Our findings provide physiological correlates to the observed distribution and movement of these shark species in their critical nursery grounds.

  11. New data on Karksiodus (Chondrichthyes from the Main Devonian Field (East European Platform

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    Alexander Ivanov

    2014-08-01

    Full Text Available New teeth belonging to Karksiodus mirus Ivanov & Märss (Chondrichthyes were found together with putative chondrichthyan scales in five new localities of the Leningrad Region, northwestern Russia, within the Aruküla and Burtnieki regional stages, Givetian, Middle Devonian. The teeth exhibit variability in the number of cusps, angles between the lateral cusps, base curvature, length of lateral parts and the prominence of the wall of the transversal basal canal. Karksiodus tooth material collected from these sites suggests that this taxon possesses an heterodont dentition and a specific, complex vascularization system affecting the dental base and the crown. Enameloid tissue seems to be absent, thus the surface striations on the cusps are presumably made up by orthodentine. The fish fauna from these localities is listed.

  12. Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus (Carcharhiniformes, Triakidae from off Tunisia

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    Boudaya Lobna

    2016-01-01

    Full Text Available Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae, Merizocotylinae is described from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus collected from the coastal marine waters off Tunisia. The new parasite species is distinguished from the other two species of the genus, T. japanicae Kearn, 1993 and T. chisholmae Justine, 2009, by the morphology of the sclerotised male copulatory organ which has longitudinal ridges. The species is also characterised by its oötype with short descending and ascending limbs (long and more convoluted in the other two species. The presence of three peripheral loculi, which is the main characteristic of the genus Triloculotrema Kearn, 1993, is unconfirmed. This is the first description of a species of this genus in the Mediterranean Sea and the first record from a coastal shark.

  13. Early Pliocene fishes (Chondrichthyes, Osteichthyes from Gran Canaria and Fuerteventura (Canary Islands, Spain

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    J. F. Betancort

    2016-11-01

    Full Text Available Fossil fish teeth are contained in marine deposits dated at ca 4.8 Ma found on the islands of Gran Canaria and Fuerteventura (Canary Islands, Spain. These islands, situated in the North Atlantic Subtropical Gyre, can be considered a mid-way stopover point between the Caribbean Sea, with the Central American Seaway about to close in this epoch, and the Mediterranean, in the first stage of its post-Messinian Gibraltar Seaway period. Accordingly, there existed extensive pantropical communication, particularly for nektonic animals capable of travelling large distances. In this paper, we present a number of fossil fishes, most of which are identified for the first time on the basis of their teeth: the Chondrichthyes species Carcharocles megalodon, Parotodus benedeni, Cosmopolitodus hastalis, Isurus oxyrinchus, Carcharias cf. acutissima, Carcharhinus cf. leucas, Carcharhinus cf. priscus, Galeocerdo cf. aduncus, and the Osteichthyes species Archosargus cinctus, Labrodon pavimentatum, and Diodon scillae. Coincidences are observed between these ichthyofauna and specimens found in the Azores Islands, the Pacific coast of America and the Mediterranean Sea.

  14. Morphological observations of ampullae of lorenzini in Squatina guggenheim and S. occulta (Chondrichthyes, Elasmobranchii, Squatinidae).

    Science.gov (United States)

    Tavares Schäfer, Bárbara; Malavasi, Carlos Eduardo; Favaron, Phelipe Oliveira; Ambrósio, Carlos Eduardo; Miglino, Maria Angelica; Ferreira De Amorim, Alberto; Grassi Rici, Rose Eli

    2012-09-01

    We have conducted a morphological study of the ampullae of Lorenzini on two shark species from Squatina Genus. In both species, S. guggenheim and S. occulta, the ampullae were observed like small pores scattered in the head region similar to other species of the Chondrichthyes Class. However, differently of the other species a greatest density of ampullae of Lorenzini was observed along of the body surface. After fixation using 10% formaldehyde, the ampullae were removed and processed for light and scanning electron microscopy. Macroscopically, the two shark species differed by the presence of dorsal spines that appeared from the head to the first dorsal fin in S. guggenheim and were absent in S. occulta. Microscopically, there were no differences between the ampullae of Lorenzini channels in these two species. The wall of the ampulla was formed by a simple squamous epithelium. Bands of connective tissue, hyaline cartilage and collagen fibers were found between the ampulla and the skeletal striated muscle layer. Nerve branches responsible for conducting signal pulses to the central nervous system were visible between the muscle and connective tissue layers. Using scanning electron microscopy and histological analysis, we found that the channels were twisted and positioned parallel to the skin. The inside of the channels contained a large amount of a gelatinous secretion composed by polysaccharides. Therefore, we conclude that the morphological combination of extended distribution of the ampullae of Lorenzini and the body shape may represent an adaptation of these species to their way of life.

  15. Morfometria de raias continentais (Chondrichthyes, Potamotrygonidae do alto rio Paraná, Brasil = Morphometry of upper Paraná river freshwater stingrays (Chondrichthyes, Potamotrygonidae

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    Antonio Guilherme Cândido da Silva

    2007-10-01

    Full Text Available Potamotrygonidae constitui o único grupo recente de Chondrichthyes cujo habitat está restrito, exclusivamente, a águas continentais. Na planície de inundação do Alto rio Paraná, espécies desta família estabeleceram-se após o fechamento das comportas da usina hidrelétrica de Itaipu, a jusante. O objetivo deste trabalho foi, utilizando medidas corporais, identificar diferenças morfométricas entre indivíduos de Potamotrygon cf. motoro (Natterer in Müller & Henle, 1841 e Potamotrygon falkneri Castex & Maciel, 1963 capturadosnesta região, bem como estimar o tamanho com que machos destas espécies atingem a maturidade gonadal. Machos de P. falkneri e P. cf. motoro das populações avaliadas atingem a maturidade gonadal com largura do disco variando em torno de 26 cm e 23 cm, respectivamente. Na comparação das espécies, P. cf. motoro apresentou maior distânciaproporcional entre as narinas e maior comprimento proporcional da cauda e dos espiráculos. Identificou-se dimorfismo sexual secundário para P. falkneri, consistindo da presença de fileiras laterais de espinhos na cauda das fêmeas. Estudos futuros de morfologiafuncional e ecomorfologia poderão esclarecer o significado das diferenças morfométricas para o modo de vida destas espécies.Potamotrygonidae is the only extant chondrichthyan group restricted exclusively to freshwater. This family invaded the UpperParaná river system after the closing of Itaipu Dam. This study aimed to identify morphometric differences between Potamotrygon cf. motoro (Natterer in Müller & Henle, 1841 and Potamotrygon falkneri Castex & Maciel, 1963 sampled in that area, and estimate male size at gonadal maturation. P. falkneri and P. cf. motoro males reach gonadal maturation at 26 cm and 23 cm disc width, respectively. Comparing both species, P. cf. motoro presented larger tail, spiracles and distance between nostrils. Lateral small stings on tails ofP. falkneri females were observed as secondary

  16. Immediate and delayed effects of gill-net capture on acid-base balance and intramuscular lactate concentration of gummy sharks, Mustelus antarcticus.

    Science.gov (United States)

    Frick, Lorenz H; Walker, Terence I; Reina, Richard D

    2012-06-01

    Many sharks are captured as untargeted by-catch during commercial fishing operations and are subsequently discarded. A reliable assessment of the proportion of discarded sharks that die post-release as a result of excessive physiological stress is important for fisheries management and conservation purposes, but a reliable physiological predictor of post-release mortality has not been identified. To investigate effects of gill-net capture on the acid-base balance of sharks, we exposed gummy sharks, Mustelus antarcticus, to 60 min of gill-net capture in a controlled setting, and obtained multiple blood and muscle tissue samples during a 72-h recovery period following the capture event. Overall mortality of gummy sharks was low (9%). Blood pH was significantly depressed immediately after the capture event due to a combination of respiratory and metabolic acidosis. Maximum concentrations of plasma lactate (9.9 ± 1.5 mmol L(-1)) were measured 3h after the capture event. Maximum intramuscular lactate concentrations (37.0 ± 4.6 μmol g(-1)) were measured immediately after the capture event, and intramuscular lactate concentrations were substantially higher than plasma lactate concentrations at all times. Sharks in poor condition had low blood pH and high intramuscular lactate concentration, but blood pH does not appear to be a reliable predictor of survival. Suitability of intramuscular lactate concentration as predictor of delayed mortality deserves further investigation.

  17. [Reproduction and feeding habits of Mustelus dorsalis (Pisces: Triakidae) in the Gulf of Nicoya, Costa Rica: elements for a sustainable management].

    Science.gov (United States)

    Rojas M, José Rodrigo

    2006-09-01

    A total of 311 sharptooth smooth-hound Mustelus dorsalis were collected in the Gulf of Nicoya, Costa Rica from March 1999 to May 2000 to determine reproduction and feeding habits. The fishes were collected using hook and line. 250 females and 61 males were identified. The females are bigger (550-660 mm) and heavier (400-1,000 g) than males (500-585 mm and 200-300 g, respectively). All samples collected were mature and the minimum length to first maturity observed is 500 and 541 mm for females and males, respectively. From September to March individuals were mature, while samples caught during April and August were immature. A total of 1,259 embryos were analyzed. Number of embryos per liter ranged from two to six, the total length is from 130 to 205 mm and the weight from 6 to 35 g. This shark is a polyphagous opportunistic carnivore that preys on crustaceans (Squilla hancocki, S. parva, Litopenaeus sp.), fishes (Anchoa sp., Caranx sp., Lutjanus sp., Engraulis sp.) and mollusks (Loligo sp. and Octopus sp.). Main prey item was S. hancocki. The presence of mature sharks of both sexes along the year and the consumption of food items associated to shallow coastal rocky waters suggest that this sector of Nicoya Gulf is a nursery ground and an essential habitat. Based on these results the establishment of an integral management plan is proposed.

  18. Size of catch, reproduction and feeding of the small-eye smooth-hound, Mustelus higmani (Carcharhiniformes: Triakidae, in Margarita Island, Venezuela

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    Alejandro Tagliafico

    2015-12-01

    Full Text Available Mustelus higmani is categorized as “least concern” according to the red list of the International Union for Conservation of Nature, but gaps in population trends occur in most of its distribution range. In Venezuela, this species has local importance because it is part of typical dishes. The aim of this work is to analyse the population structure, reproduction and feeding of M. higmani from Margarita Island’s artisanal fishery landings for management purposes. Between 2006 and 2008, 2223 specimens were analysed: 1156 females (24.8-88.4 cm total length [TL] and 1067 males (20-69.2 cm TL. Temporal variations in sex ratio and length class structure were detected. Changes in body size were detected throughout different years of sampling. A decrease in TL and an increase in immature specimens in the catch were observed in 2008. Mean length at maturity (L50 was estimated at 46.7 cm TL for females and 47.6 cm TL for males. Female fecundity was 4±1.8 embryos (n=388. Length at birth was between 20 and 29 cm TL, and no differences in sex ratio were detected for embryos. Feeding analyses (n=266 stomachs showed a diet mainly based on decapod crustaceans, small fish, stomatopods and cephalopods. The trophic level was 3.3, which shows feeding based on benthic and demersal species of the continental shelf, especially crustaceans.

  19. Histological and Morphological Aspects of Reproduction in Male Blackspotted Smooth-Hound Mustelus punctulatus in the Adriatic Sea (Eastern Mediterranean Sea

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    Romana Gračan

    2016-01-01

    Full Text Available We present first data on reproductive biology of male blackspotted smooth-hound Mustelus punctulatus in the Adriatic Sea and first histological examination of gonads at different maturation stages and seasonal cycles for this species. We collected samples from 117 male specimens of M. punctulatus ranging in length from 44.6 to 126.5 cm, caught by commercial bottom trawls in the North-Central Adriatic Sea. Microscopic observation revealed a diametric development of testes, in which round-shaped spermatocysts have zonal arrangement, showing seven different stages of development. Males began to mature when they were between 61 and 88 cm body length, which was indicated by the presence of functional claspers or appearance of the spermatogenic cysts. While the smallest mature shark was only 80 cm long, all animals longer than 89 cm were sexually mature. The seasonal analysis of the testes indicated that mature spermatozoa dominated in testes during the first half of the year with a peak in May and June, after which followed less active period during July and August.

  20. Development of the Synarcual in the Elephant Sharks (Holocephali; Chondrichthyes): Implications for Vertebral Formation and Fusion.

    Science.gov (United States)

    Johanson, Zerina; Boisvert, Catherine; Maksimenko, Anton; Currie, Peter; Trinajstic, Kate

    2015-01-01

    The synarcual is a structure incorporating multiple elements of two or more anterior vertebrae of the axial skeleton, forming immediately posterior to the cranium. It has been convergently acquired in the fossil group 'Placodermi', in Chondrichthyes (Holocephali, Batoidea), within the teleost group Syngnathiformes, and to varying degrees in a range of mammalian taxa. In addition, cervical vertebral fusion presents as an abnormal pathology in a variety of human disorders. Vertebrae develop from axially arranged somites, so that fusion could result from a failure of somite segmentation early in development, or from later heterotopic development of intervertebral bone or cartilage. Examination of early developmental stages indicates that in the Batoidea and the 'Placodermi', individual vertebrae developed normally and only later become incorporated into the synarcual, implying regular somite segmentation and vertebral development. Here we show that in the holocephalan Callorhinchus milii, uniform and regular vertebral segmentation also occurs, with anterior individual vertebra developing separately with subsequent fusion into a synarcual. Vertebral elements forming directly behind the synarcual continue to be incorporated into the synarcual through growth. This appears to be a common pattern through the Vertebrata. Research into human disorders, presenting as cervical fusion at birth, focuses on gene misexpression studies in humans and other mammals such as the mouse. However, in chondrichthyans, vertebral fusion represents the normal morphology, moreover, taxa such Leucoraja (Batoidea) and Callorhinchus (Holocephali) are increasingly used as laboratory animals, and the Callorhinchus genome has been sequenced and is available for study. Our observations on synarcual development in three major groups of early jawed vertebrates indicate that fusion involves heterotopic cartilage and perichondral bone/mineralised cartilage developing outside the regular skeleton. We

  1. Development of the Synarcual in the Elephant Sharks (Holocephali; Chondrichthyes: Implications for Vertebral Formation and Fusion.

    Directory of Open Access Journals (Sweden)

    Zerina Johanson

    Full Text Available The synarcual is a structure incorporating multiple elements of two or more anterior vertebrae of the axial skeleton, forming immediately posterior to the cranium. It has been convergently acquired in the fossil group 'Placodermi', in Chondrichthyes (Holocephali, Batoidea, within the teleost group Syngnathiformes, and to varying degrees in a range of mammalian taxa. In addition, cervical vertebral fusion presents as an abnormal pathology in a variety of human disorders. Vertebrae develop from axially arranged somites, so that fusion could result from a failure of somite segmentation early in development, or from later heterotopic development of intervertebral bone or cartilage. Examination of early developmental stages indicates that in the Batoidea and the 'Placodermi', individual vertebrae developed normally and only later become incorporated into the synarcual, implying regular somite segmentation and vertebral development. Here we show that in the holocephalan Callorhinchus milii, uniform and regular vertebral segmentation also occurs, with anterior individual vertebra developing separately with subsequent fusion into a synarcual. Vertebral elements forming directly behind the synarcual continue to be incorporated into the synarcual through growth. This appears to be a common pattern through the Vertebrata. Research into human disorders, presenting as cervical fusion at birth, focuses on gene misexpression studies in humans and other mammals such as the mouse. However, in chondrichthyans, vertebral fusion represents the normal morphology, moreover, taxa such Leucoraja (Batoidea and Callorhinchus (Holocephali are increasingly used as laboratory animals, and the Callorhinchus genome has been sequenced and is available for study. Our observations on synarcual development in three major groups of early jawed vertebrates indicate that fusion involves heterotopic cartilage and perichondral bone/mineralised cartilage developing outside the regular

  2. Characterization of the functional and anatomical differences in the atrial and ventricular myocardium from three species of elasmobranch fishes: smooth dogfish (Mustelus canis), sandbar shark (Carcharhinus plumbers), and clearnose skate (Raja eglanteria)

    DEFF Research Database (Denmark)

    Larsen, Julie; Bushnell, Peter; Steffensen, John;

    2016-01-01

    We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca2+ release from the sarcoplasmic reticulum (SR) with ryanodine...... positive first derivative (i.e., contractility), and increased time to 50 % relaxation in atrial tissue from smooth dogfish at 30 °C. It also increased times to peak force and half relaxation in clearnose skate atrial and ventricular tissue at both temperatures, but only in atrial tissue from sandbar shark...

  3. Pass the salt: physiological consequences of ecologically relevant hyposmotic exposure in juvenile gummy sharks (Mustelus antarcticus) and school sharks (Galeorhinus galeus)

    Science.gov (United States)

    Morash, Andrea J.; Mackellar, Sara R. C.; Tunnah, Louise; Barnett, David A.; Stehfest, Kilian M.; Semmens, Jayson M.; Currie, Suzanne

    2016-01-01

    Estuarine habitats are frequently used as nurseries by elasmobranch species for their protection and abundant resources; however, global climate change is increasing the frequency and severity of environmental challenges in these estuaries that may negatively affect elasmobranch physiology. Hyposmotic events are particularly challenging for marine sharks that osmoconform, and species-specific tolerances are not well known. Therefore, we sought to determine the effects of an acute (48 h) ecologically relevant hyposmotic event (25.8 ppt) on the physiology of two juvenile shark species, namely the school shark (Galeorhinus galeus), listed by the Australian Environmental Protection and Biodiversity Conservation Act as ‘conservation dependent’, and the gummy shark (Mustelus antarcticus), from the Pittwater Estuary (Australia). In both species, we observed a decrease in plasma osmolality brought about by selective losses of NaCl, urea and trimethylamine N-oxide, as well as decreases in haemoglobin, haematocrit and routine oxygen consumption. Heat-shock protein levels varied between species during the exposure, but we found no evidence of protein damage in any of the tissues tested. Although both species seemed to be able to cope with this level of osmotic challenge, overall the school sharks exhibited higher gill Na+/K+-ATPase activity and ubiquitin concentrations in routine and experimental conditions, a larger heat-shock protein response and a smaller decrease in routine oxygen consumption during the hyposmotic exposure, suggesting that there are species-specific responses that could potentially affect their ability to withstand longer or more severe changes in salinity. Emerging evidence from acoustic monitoring of sharks has indicated variability in the species found in the Pittwater Estuary during hyposmotic events, and together, our data may help to predict species abundance and distribution in the face of future global climate change. PMID:27757235

  4. Geo(Im)pulseBite marks on early Holocene Tursiops truncatus fossils from the North Sea indicate scavenging by rays (Chondrichthyes, Rajidae)

    OpenAIRE

    Netten, H.H. van; Reumer, J.W.F.

    2010-01-01

    A number of Tursiops truncatus mandibles in the collection of fossil marine mammals in the Rotterdam Natural History Museum have marks consisting of several parallel linear grooves. These marks are also found on four atlas complexes, a scapula and on one vertebra. The hypothesis that they are bite marks and were caused by scavenging rays (Rajidae, Chondrichthyes) was tested with a real-life experiment using different shark and ray species, allowing them to scavenge on cow ribs as proxies for ...

  5. Lista patrón de los tiburones, rayas y quimeras (Chondrichthyes, Elasmobranchii, Holocephali de México

    Directory of Open Access Journals (Sweden)

    Del Moral-Flores, L. F.

    2015-09-01

    Full Text Available Checklist of sharks, rays and chimaeras (Chondrichthyes, Elasmobranchii, Holocephali from Mexico We present an annotated checklist of the species of sharks, rays and chimaeras (chondrichthyan fishes occurring in Mexican waters, based on a thorough review of the literature and electronic database searches, examination of museum collection specimens, and unpublished records obtained during fieldwork conducted in the last four years. The checklist contains information of at least 214 species of chondrichthyan fishes that occur in Mexican marine and brackish waters, assigned to 84 genera, 40 families and 14 orders. It includes eight species of chimaeras, 95 batoids and 111 sharks. Condrichthyan fauna in Mexico is one of the richest in the world, with almost 17.3% of the known species. An additional 16 species are included as their occurrence in Mexican marine waters is probable according to distributional patterns. Data published through GBIF [doi:10.15470/hrl1kv

  6. Lista patrón de los tiburones, rayas y quimeras (Chondrichthyes, Elasmobranchii, Holocephali de México

    Directory of Open Access Journals (Sweden)

    Del Moral-Flores, L. F.

    2016-04-01

    Full Text Available Checklist of sharks, rays and chimaeras (Chondrichthyes, Elasmobranchii, Holocephali from Mexico We present an annotated checklist of the species of sharks, rays and chimaeras (chondrichthyan fishes occurring in Mexican waters, based on a thorough review of the literature and electronic database searches, examination of museum collection specimens, and unpublished records obtained during fieldwork conducted in the last four years. The checklist contains information of at least 214 species of chondrichthyan fishes that occur in Mexican marine and brackish waters, assigned to 84 genera, 40 families and 14 orders. It includes eight species of chimaeras, 95 batoids and 111 sharks. Condrichthyan fauna in Mexico is one of the richest in the world, with almost 17.3% of the known species. An additional 16 species are included as their occurrence in Mexican marine waters is probable according to distributional patterns.

  7. The marine leech Stibarobdella loricata (Harding, 1924 (Hirudinea, Piscicolidae, parasitic on the angel shark Squatina spp. and sandtiger shark Carcharias taurus Rafinesque, 1810 (Chondrichthyes: Squatinidae, Carchariidae in Southern Brazilian waters

    Directory of Open Access Journals (Sweden)

    Soto J. M. R.

    2003-01-01

    Full Text Available The presence of the marine leech, Stibarobdella loricata (Harding, 1924 (Hirudinea, Piscicolidae, is reported on the southern coast of Brazil, based on seven lots with 47 specimens, between 71 and 182 mm in total length, collected on the dorsal region of angel sharks, Squatina argentina (Marini, 1930; S. guggenheim Marini, 1936; S. punctata Marini, 1936 (Chondrichthyes, Squatinidae; and on the head of a sandtiger shark, Carcharias taurus Rafinesque, 1810 (Chondrichthyes, Carchariidae. This is the first record of S. loricata in the western Atlantic and of its parasitic association with S. argentina, S. guggenheim, S. punctata, and C. taurus.

  8. Effects of juvenile hormone antagonist KK-42 on temporal and spatial expressions of FAMeT in shrimp Penaeus schmitti%保幼激素拮抗物KK-42对凡纳滨对虾FAMeT时空表达的影响

    Institute of Scientific and Technical Information of China (English)

    夏西超; 王雪参; 李昕; 吕黎; 宁黔冀

    2011-01-01

    It has been demonstrated that the treatment of juvenile hormone antagonist KK-42 can significantly accelerate growth of Penaeus schmitti, which has been applied in P. schmitti aquaculture, but the mechanism of KK-42 is unclear. To provide the theory support involved in KK-42 application, the temporal and spatial expressions of farnesoic acid O-methyltransferase (FAMeT), a key synthesis enzyme of methyl farnesoate (MF) which is the important hormone regulating directly crustacean growth, was assayed and the effect of KK-42 on the enzyme was researched. The shrimps (Penaeus schmitti), 3.5-5.0 cm long, were randomly divided into two groups, soaked in KK-42 solution at a concentration of 1.95×10-4 mol/L or in the solution without KK-42 for 1 min, respectively,and then cultured in normal way. The levels of FAMeT mRNA were determined using real-time PCR and hemolymph MF titer was analyzed by normal phase high-performance liquid chromatography. Results showed that the expression pattern of FAMeT derived from the muscle, eyestalk and mandibular organ (MO) tissues varied in control, of which, the mRNA levels in muscle and eyestalk tissues were not only relatively low but also little various during the experiment. However, an obvious fluctuation of mRNA level occurred in MO during the stage of experiment, more than l-fold of increase in mRNA level was observed on days 2, 6, 7, and 8 comparing to that on day 0. The hemolymph MF content in control shrimps rose during the experiment. Administration of KK-42 resulted in the universal depression on FAMeT expression in three tissues mentioned above; the most significant inhibitory effect occurred in MO where the level of FAMeT mRNA was considerably lower than that in control group from day 1 to day 7; the level even decreased to 50.9% (P<0.01), 63.4% (P<0.01) and 55.7% (P<0.01)on dayl, day 4 and day 6 after KK-42 treatment, respectively. Meanwhile, the amount of hemolymph MF fell in KK-42-treated shrimps compared to

  9. Testing morphologically based phylogenetic theories within the cartilaginous fishes with molecular data, with special reference to the catshark family (Chondrichthyes; Scyliorhinidae) and the interrelationships within them.

    Science.gov (United States)

    Human, Brett A; Owen, E Patricia; Compagno, Leonard J V; Harley, Eric H

    2006-05-01

    A molecular phylogenetic investigation was conducted to examine phylogenetic relationships between various members of the catsharks (Chondrichthyes; Carcharhiniformes; Scyliorhinidae), and is the largest chondrichthyan data set yet analysed, consisting of nearly 130,000 nucleotides. Three mitochondrial DNA genes were used to construct the phylogenies, cytochrome b, NADH-2, and NADH-4, with 41 sequences from 18 taxa being novel. These sequences were either used separately or combined into a single data set, and phylogenies were constructed using various methods, however, only the Bayesian inference tree derived from the cytochrome b data set was resolved sufficiently for phylogenetic inferences to be made. Interestingly, the family Scyliorhinidae was not supported by the results and was found to be paraphyletic. The Scyliorhininae and Pentanchinae were supported, whereas the Pentanchini clade was present, but not well supported. The Halaelurini hypothesis was supported with Holohalaelurus identified as the basal genus of that clade, and Haploblepharus edwardsii identified as the basal taxon for that genus. Elsewhere within the Chondrichthyes, the Carcharhiniformes and the Lamniformes were found to be monophyletic, and the Heterodontiformes was placed within the Squalimorphs. The placement of the skates and rays in these analyses support the Batoidea as being sister to the Elasmobranchii.

  10. Reproducción y alimentación del tiburón enano Mustelus dorsalis (Pisces: Triakidae en el Golfo de Nicoya, Costa Rica: Elementos para un manejo sostenible

    Directory of Open Access Journals (Sweden)

    José Rodrigo Rojas M

    2006-09-01

    Full Text Available Se determinaron aspectos reproductivos y alimentarios del tiburón enano Mustelus dorsalis, a partir de 311 ejemplares capturados con línea y anzuelo en el Golfo de Nicoya, Costa Rica, durante marzo de 1999 y mayo de 2000. Se reconocieron 250 hembras y 61 machos. Las hembras son más grandes (550 a 660 mm vs. (500-585 mm y más pesadas (400-1 000 g vs. (200-300 g que los machos. Todos los ejemplares estaban maduros, la talla mínima de especimenes maduros fue de 500 y 541 mm para hembras y machos respectivamente. Entre septiembre y marzo todas las hembras y machos estaban maduras, e inmaduras entre abril y agosto. Se estudiaron 1 259 embriones, con una variación entre dos y seis embriones por litera. La longitud total de los embriones es entre 130 y 205 mm y el peso entre 6 y 35 g. Este tiburón es carnívoro polífago oportunista que consume crustáceos (Squilla hancocki, S. parva, Farfantepenaeus sp., peces (Anchoa sp. Caranx, sp, Lujanus sp., Engraulis y Ophistonema sp., y moluscos (Loligo sp. y Octopus sp.. Squilla hancocki es el ítem alimentario mas importante. La presencia de tiburones maduros de ambos sexos a lo largo del año en aguas poco profundas, y el consumo de presas bentónicas que viven en fondos rocosos costeros, sugiere la posibilidad de que este sector del Golfo de Nicoya esté funcionando como una zona de crianza y hábitat esencial. Con base en estos resultados se propone el establecimiento de un plan de manejo integral.Reproduction and feeding habits of Mustelus dorsalis (Pisces: Triakidae in the Gulf of Nicoya, Costa Rica: Elements for a sustainable management. A total of 311 sharptooth smooth-hound Mustelus dorsalis were collected in the Gulf of Nicoya, Costa Rica from March 1999 to May 2000 to determine reproduction and feeding habits. The fishes were collected using hook and line. 250 females and 61 males were identified. The females are bigger (550-660 mm and heavier (400-1 000 g than males (500-585 mm and 200-300 g

  11. Effects of species, sex, length, and locality on the mercury content of school shark Galeorhinus australis (Macleay) and gummy shark Mustelus antarcticus Guenther from south-eastern Australian waters

    Energy Technology Data Exchange (ETDEWEB)

    Walker, T.I.

    1976-12-01

    The mercury levels detected in the muscle tissues of sharks ranged from 0.01 to 2.7 ppM wet weight for school shark Galeorhinus australis (Macleay) and from 0.07 to 3.0 ppM for gummy shark Mustelus antarcticus Guenther. Estimates of the mean mercury levels for the 1971 Victorian landed commercial shark catch were found to be 0.90 ppM for the school shark and 0.37 ppM for the gummy shark. The analyses for total mercury determinations were carried out by five independent laboratories. Preliminary analyses carried out by one indicated that most of the mercury in school sharks and about two-thirds of the mercury in gummy sharks was present as methylmercury. The mercury concentrations varied exponentially with shark length. School sharks had statistically significant higher mercury levels than gummy sharks of the same length and for both the medium-sized and large individuals of each species males had significantly higher levels than females. Levels in male gummy sharks were found to be affected by locality.

  12. The ovary of the bignose fanskate Sympterygia acuta Garman, 1877 (Chondrichthyes, Rajidae) in the Bahía Blanca estuary, Argentina: morphology and reproductive features.

    Science.gov (United States)

    Díaz-Andrade, M C; Galíndez, E; Estecondo, S

    2009-05-01

    Chondrichthyes have become an important economic resource in recent years. In spite of this importance, there is little knowledge about their reproductive biology, especially of species from the south-western Atlantic. In this work, we study the morphology and histology of the ovary of Sympterygia acuta. The results show that oogonia were present only in the immature females (stage I of maturity scale), whereas specimens in stages II and III of maturity displayed oocytes in all developmental steps. The most important histological features that vary throughout oocyte development are the presence or absence of yolk, the number of types and layers of follicular cells and the degree of development of the thecae. Follicular cells are, at least, of two different types. Finally, a new point of view for the determination of maturity stages in the field based on the size of follicles is discussed.

  13. Digenea, Nematoda, Cestoda, and Acanthocephala, parasites in Potamotrygonidae (Chondrichthyes from the upper Paraná River floodplain, states of Paraná and Mato Grosso do Sul, Brazil.

    Directory of Open Access Journals (Sweden)

    Pavanelli, G. C.

    2008-01-01

    Full Text Available The present paper represents the first study on the endoparasitic fauna of Potamotrygon falkneri and P.motoro in the upper Paraná River floodplain. Fishes were collected by fishing rod and gillnetting in different stations ofthe floodplain, from March, 2005 to September, 2006. Parasites were sampled, fixed and preserved according tospecialized literature. About half of the analyzed fish were parasitized by at least one of the following species ofendoparasites: Clinostomum complanatum, Genarchella sp. and Tylodelphys sp. (metacercaria (Digenea;Acanthobothrium regoi, Rhinebothrium paratrygoni, Paroncomegas araya and Potamotrygonocestus travassosi(Cestoidea; Brevimulticaecum sp. (larva, Cucullanus sp., Echinocephalus sp. and Spinitectus sp. (Nematoda; andQuadrigyrus machadoi (Acanthocephala. Some species were already registered in Chondrichthyes and others werepreviously recorded in Osteichthyes from the study area. The study listed ten new records of parasites in the host P.falkneri, one new record in the host P. motoro and five new records in the locality upper Paraná River.

  14. Characterization of the functional and anatomical differences in the atrial and ventricular myocardium from three species of elasmobranch fishes: smooth dogfish (Mustelus canis), sandbar shark (Carcharhinus plumbeus), and clearnose skate (Raja eglanteria).

    Science.gov (United States)

    Larsen, Julie; Bushnell, Peter; Steffensen, John; Pedersen, Morten; Qvortrup, Klaus; Brill, Richard

    2017-02-01

    We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca(2+) release from the sarcoplasmic reticulum (SR) with ryanodine and thapsigargin and measuring the resultant changes in contraction-relaxation parameters and the force-frequency relationship at 20 °C and 30 °C. We also examined ultrastructural differences with electron microscopy. In tissues from smooth dogfish, net force (per cross-sectional area) and measures of the speeds of contraction and relaxation were all higher in atrial than ventricular myocardium at both temperatures. Atrial-ventricular differences were evident in the other two species primarily in measures of the rates of contraction and relaxation. Ryanodine-thapsigargin treatment reduced net force and its maximum positive first derivative (i.e., contractility), and increased time to 50 % relaxation in atrial tissue from smooth dogfish at 30 °C. It also increased times to peak force and half relaxation in clearnose skate atrial and ventricular tissue at both temperatures, but only in atrial tissue from sandbar shark at 30 °C; indicating that SR involvement in excitation-contraction (EC) coupling is species- and temperature-specific in elasmobranch fishes, as it is in teleost fishes. Atrial and ventricular myocardium from all three species displayed a negative force-frequency relationship, but there was no evidence that SR involvement in EC coupling was influenced by heart rate. SR was evident in electron micrographs, generally located in proximity to mitochondria and intercalated discs, and to a lesser extent between the myofibrils; with mitochondria being more numerous in ventricular than atrial myocardium in all three species.

  15. Morphological and molecular characterization of a new myxozoan species (Myxosporea) infecting the gall bladder of Raja clavata (Chondrichthyes), from the Portuguese Atlantic Coast.

    Science.gov (United States)

    Rocha, S; Casal, G; Al-Quraishy, S; Azevedo, C

    2013-04-01

    Microscopic and molecular procedures are used to describe a new myxosporean species, Chloromyxum clavatum n. sp., infecting the cartilaginous fish Raja clavata Linnaeus, 1758 (Chondrichthyes: Rajidae), collected from the northwest Atlantic coast of Portugal. Young plasmodia and mature spores were found floating free in the gall bladder of R. clavata . Spores were spherical to subspherical with a pointed anterior end, measuring14.4 ± 0.5 μm (n = 25) in length, 11.9 ± 0.5 μm (n = 25) in width, and 9.4 ± 0.5 μm (n = 15) in thickness. The spore's wall was composed of 2 equally sized valves, each displaying 6-8 elevated surface ridges and a bundle of several tapering caudal filaments attached to the basal portion. Spores contained 4 pyriform equally sized polar capsules (5.5 ± 0.4 μm × 2.9 ± 0.5 μm) (n = 25), each possessing an obliquely arranged isofilar polar filament coiled in 7-8 coils. Morphological data, host specificity, tissue tropism, and molecular analysis of the SSU rDNA gene identify this parasite as a new species of Chloromyxum. Neighbor-joining and maximum likelihood further reveal the parasite clustering with other species of Chloromyxum infecting the gall bladder of marine cartilaginous fish to form a clade positioned at the base of the freshwater clade, therefore constituting an exception to the major division of the class Myxosporea into the freshwater and marine clades, while supporting the existence of a correlation between tissue tropism and myxosporean phylogeny.

  16. The genus Mustelus (Family Triakidae, Order Carcharhiniformes ...

    African Journals Online (AJOL)

    spamer

    Eastern Atlantic Ocean and the Mediterranean Sea ... African coast. ... sectioned vertebral centra of 136 specimens, using a modified Alizarin red S technique to stain ... Port Elizabeth Museum, P.O. Box 13147, Humewood 6013, South Africa.

  17. Catálogo dos Peixes Marinhos do Laboratório de Ictiologia da Universidade Federal do Rio de Janeiro. Parte I: Chondrichthyes (Rajiformes. Teleostei (Elopiformes a Dactylopteriformes

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Duarte Lopes

    1989-01-01

    Full Text Available The present paper is the first part of the catalogue of marine fishes belonging to the collection of the Laboratory of Ichthyology (Universidade Federal do Rio de Janeiro-RJ to be published. Here are included Chondrichthyes (Rajiformes and part of Osteichthyes, Teleostei (Elopiformes to Dactylopteriformes in a total amount of 30 families, 52 genera and 62 species. The most part of the material have been collected at the littoral of the State of Rio de Janeiro. For each species considered is given the vulgar name (when known in Southeastern Brazil, the known distribution (in Western Atlantic Ocean and some data as collecting locality, total number of collected specimens and the register number in the collection. Scorpaena isthmensis Meek & Hildebrand, 1928 (Scorpaenidae is for the first time mentioned for the Southern littoral of Brazil.

  18. Morfometria de raias continentais (Chondrichthyes, Potamotrygonidae do alto rio Paraná, Brasil - DOI: 10.4025/actascibiolsci.v29i4.885 Morphometry of upper Paraná river freshwater stingrays (Chondrichthyes, Potamotrygonidae - DOI: 10.4025/actascibiolsci.v29i4.885

    Directory of Open Access Journals (Sweden)

    Erivelto Goulart

    2008-02-01

    Full Text Available Potamotrygonidae constitui o único grupo recente de Chondrichthyes cujo habitat está restrito, exclusivamente, a águas continentais. Na planície de inundação do Alto rio Paraná, espécies desta família estabeleceram-se após o fechamento das comportas da usina hidrelétrica de Itaipu, a jusante. O objetivo deste trabalho foi, utilizando medidas corporais, identificar diferenças morfométricas entre indivíduos de Potamotrygon cf. motoro (Natterer in Müller & Henle, 1841 e Potamotrygon falkneri Castex & Maciel, 1963 capturados nesta região, bem como estimar o tamanho com que machos destas espécies atingem a maturidade gonadal. Machos de P. falkneri e P. cf. motoro das populações avaliadas atingem a maturidade gonadal com largura do disco variando em torno de 26 cm e 23 cm, respectivamente. Na comparação das espécies, P. cf. motoro apresentou maior distância proporcional entre as narinas e maior comprimento proporcional da cauda e dos espiráculos. Identificou-se dimorfismo sexual secundário para P. falkneri, consistindo da presença de fileiras laterais de espinhos na cauda das fêmeas. Estudos futuros de morfologia funcional e ecomorfologia poderão esclarecer o significado das diferenças morfométricas para o modo de vida destas espécies.Potamotrygonidae is the only extant chondrichthyan group restricted exclusively to freshwater. This family invaded the Upper Paraná river system after the closing of Itaipu Dam. This study aimed to identify morphometric differences between Potamotrygon cf. motoro (Natterer in Müller & Henle, 1841 and Potamotrygon falkneri Castex & Maciel, 1963 sampled in that area, and estimate male size at gonadal maturation. P. falkneri and P. cf. motoro males reach gonadal maturation at 26 cm and 23 cm disc width, respectively. Comparing both species, P. cf. motoro presented larger tail, spiracles and distance between nostrils. Lateral small stings on tails of P. falkneri females were observed as

  19. Uso de marcas convencionales en un país con escasa experiencia en marcación de peces marinos

    OpenAIRE

    Marcelo Pérez; Matías Braccini; M. Berta Cousseau

    2014-01-01

    La utilización del marcado mediante distintas técnicas ha sido reconocida como un valioso medio para estudiar distintos aspectos poblacionales de especies de peces marinos. El Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP) de Argentina, diseñó una actividad para la utilización de la técnica de marcado y recaptura mediante marcas convencionales en un tiburón demersal-bentónico "gatuzo" (Mustelus schmitti), para establecer desplazamientos de la especie en el Ecosistema Coste...

  20. Dental homologies in lamniform sharks (Chondrichthyes: Elasmobranchii).

    Science.gov (United States)

    Shimada, Kenshu

    2002-01-01

    The dentitions of lamniform sharks are said to exhibit a unique heterodonty called the "lamnoid tooth pattern." The presence of an inflated hollow "dental bulla" on each jaw cartilage allows the recognition of homologous teeth across most modern macrophagous lamniforms based on topographic correspondence through the "similarity test." In most macrophagous lamniforms, three tooth rows are supported by the upper dental bulla: two rows of large anterior teeth followed by a row of small intermediate teeth. The lower tooth row occluding between the two rows of upper anterior teeth is the first lower anterior tooth row. Like the first and second lower anterior tooth rows, the third lower tooth row is supported by the dental bulla and may be called the first lower intermediate tooth row. The lower intermediate tooth row occludes between the first and second upper lateral tooth rows situated distal to the upper dental bulla, and the rest of the upper and lower tooth rows, all called lateral tooth rows, occlude alternately. Tooth symmetry cannot be used to identify their dental homology. The presence of dental bullae can be regarded as a synapomorphy of Lamniformes and this character is more definable than the "lamnoid tooth pattern." The formation of the tooth pattern appears to be related to the evolution of dental bullae. This study constitutes the first demonstration of supraspecific tooth-to-tooth dental homologies in nonmammalian vertebrates.

  1. Late Devonian Conodonts and Chondrichthyes from Taketai Formation in Western Junggar,NW China%晚泥盆世牙形刺及软骨鱼类在西准噶尔塔克台组中的发现及意义

    Institute of Scientific and Technical Information of China (English)

    王志宏; 纵瑞文; 龚一鸣; 王成源

    2015-01-01

    新疆西准噶尔哈拉也门地区原有一套地层划分为下石炭统和布克河组,岩性组合与标准剖面差异较大,因此,新建塔克台组.在该组参考剖面 TK01第3层含化石的灰岩透镜体中,发现了少量非常重要的浅水相牙形刺,包括3属6种1未定种:Icriodus alternatus alternatus 、Icriodus cornutus 、Icriodus expansus 、Polygnathus krestovnikovi 、Polygnathus procerus 、Polyg-nathus makhlinae 、Ancyrognathus sp.,与这些牙形刺共生的还有软骨鱼类化石 Protacrodus sp.和 Phoebodus sp..该化石组合表明,新建的塔克台组的时代为晚泥盆世法门期早期.%The Devonian Famennian conodont and chondrichthy have been found from the newly established Taketai Formation which previously was assigned to the Early Carboniferous Hebukehe Formation in Halayemen region,western Junggar.Cono-dont fossils include 3 genera,6 species and 1 indeterminate species:Icriodus alternatus alternatus ,Icriodus cornutus ,Icriodus expansus,Icriodus sp.1,Icriodus sp.2,Polygnathus krestovnikovi ,Polygnathus procerus ,Polygnathus makhlinae ,Polyg-nathus sp.1,Polygnathus sp.2,Polygnathus sp.3,Ancyrognathus sp..Chondrichthyes include 2 genera:Protacrodus sp. and Phoebodus sp..It indicates that Taketai Formation belongs to early Famennian of Late Devonian.

  2. 略论施米特的宪法思想%On the Thousht if Cart Schmittis Constitution

    Institute of Scientific and Technical Information of China (English)

    康玉娟

    2011-01-01

    施米特的宪法政治思想对后世产生了极大的影响,也渗透在中国的1982年宪法里.浓郁的政治色彩成为他的宪法思想中的一大特色,我们应辩证去看待它,尽量吸收借鉴它对我国现代法治有益的思想.

  3. Eutetrarhynchid trypanorhynchs (Cestoda) from elasmobranchs off Argentina, including the description of Dollfusiella taminii sp. n. and Parachristianella damiani sp. n., and amended description of Dollfusiella vooremi (São Clemente et Gomes, 1989).

    Science.gov (United States)

    Menoret, Adriana; Ivanov, Verónica A

    2014-10-01

    During a parasitological survey of teleosts and elasmobranchs in the Argentine Sea, 3 species of eutetrarhynchids were collected from the batoids Myliobatis goodei Garman and Psammobatis bergi Marini, and the shark Mustelus schmitti Springer. The specimens collected from Mu. schmitti were identified as Dollfusiela vooremi (Sπo Clemente et Gomes, 1989), whereas the specimens from My. goodei and Ps. bergi resulted in new species of Dollfusiella Campbell et Beveridge, 1994 and Parachristianella Dollfus, 1946, respectively. Dollfusiella taminii sp. n. from Ps. bergi is characterised by a distinct basal armature with basal swelling and a heteroacanthous homeomorphous metabasal armature with 7-9 falcate hooks per principal row. Parachristianella damiani sp. n. from My. goodei lacks a distinct basal armature, having 2-3 initial rows of uncinate hooks, a heteroacanthous heteromorphous metabasal armature with the first principal row of small hooks, followed by rows with 10-14 large hooks. This is the first record of Parachristianella in the southwestern Atlantic. The amended description of D. vooremi includes the detailed description of the tentacular armature, including SEM micrographs of all tentacular surfaces. This species is characterised by a basal armature consisting of rows of uncinate and falcate hooks, a basal swelling and a metabasal armature with billhooks on the antibothrial surface and uncinate hooks on the bothrial surface. The scolex peduncle of D. vooremi is covered with enlarged spinitriches. This species is restricted to carcharhiniform sharks, since the report of D. vooremi in Sympterygia bonapartii Müller et Henle off Bahia Blanca (Argentina) is dubious.

  4. A trans-ecosystem fishery: Environmental effects on the small-scale gillnet fishery along the Río de la Plata boundary

    Science.gov (United States)

    Jaureguizar, Andrés Javier; Cortés, Federico; Milessi, Andrés Conrado; Cozzolino, Ezequiel; Allega, Lucrecia

    2015-12-01

    To improve the understanding of the environmental processes affecting small-scale gillnet fisheries along neighboring waters of estuaries, we analyzed the main climatic forcing and the environmental conditions, the fishery landing spatial and temporal variation, including the relative importance of site, distance to coast, temperature and salinity in the structuring of landed species profile. Data were collected monthly in two sites along the adjacent south coast of the Río de la Plata between October 2009 and September 2010. The gillnet fishery was dominated by four species (Cynoscion guatucupa, Micropogonias furnieri, Mustelus schmitti and Parona signata) from a total of 38 species landed, which accounted for 98.6% of total landings. The fishing effort and landings by the fishery were largely conditioned by the availability of fish species in the fishing grounds resulting from the combination of the species reproductive behavior and the predominant environmental conditions. The highest abundances for some species occurred before (M. furnieri, C. guatucupa, P. signata) or during the reproductive period (M. schmitti, Squatina guggenheim), while in other species it was associated with favorable environmental conditions during cold months (Squalus acanthias, Callorhinchus callorhynchus, Galeorhinus galeus) or warm months (Trichiurus lepturus). The predominant seasonal environmental conditions along the coast were mainly determined by the location of Río de la Plata boundary, whose spatial extent was forced by the wind patterns and freshwater discharge. The strong environmental dependence means that the small-scale fishery is in fact a seasonal trans-ecosystem fishery. This attribute, together that shared the resources with the industrial fishery and the overlap of the fishery ground with essential habitat of sharks, make this kind of small-scale gillnet fishery particularly relevant to be included in the development of a coastal ecosystem-based management approach.

  5. An annotated bibliography of parasitic Isopoda (Crustacea of Chondrichthyes

    Directory of Open Access Journals (Sweden)

    Plínio Soares Moreira

    1978-01-01

    Full Text Available This annotated bibliography is an attempt to bring together all available published records on the parasitic isopods of Chondrichthian fishes as a basic reference source. An effort was made to synonymise old names according to the presently accepted scientific names.

  6. Large Centrophorus (Chondrichthyes, Squaliformes) of the Belgian Neogene continental shelf

    NARCIS (Netherlands)

    Schutter, de P.J.; Wijnker, E.

    2012-01-01

    A number of isolated teeth of gulper sharks (genus Centrophorus Müller & Henle, 1837) have been recovered from Neogene sands in the Antwerp area, marking the first occurrence of the genus Centrophorus in the fossil record of Belgium and the North Sea Basin. The precise stratigraphic origin of th

  7. Bransonelliformes – a new order of the Xenacanthimorpha (Chondrichthyes, Elasmobranchii

    Directory of Open Access Journals (Sweden)

    O. Hampe

    2007-08-01

    Full Text Available The order Bransonelliformes is erected for the genera Bransonella Harlton, 1933 and Barbclabornia Johnson, 2003 based on the distinct characters of an inverted "V"-nested pattern of ornamentation preliminary on the labial aspect at the tooth cusps, the presence of labial foramina, and the occasional occurrence of a centrally positioned lingual opening of a main nutrient canal at the bases of the teeth. The Bransonelliformes comprises the primitive sister group to the Xenacanthiformes within the Xenacanthimorpha. Für die Gattungen Bransonella Harlton, 1933 und Barbclabornia Johnson, 2003 wird die neue Ordnung Bransonelliformes eingeführt basierend auf den Merkmalen von bevorzugt auf der labialen Seite der Zahnspitzen auftretenden, dachziegelartig ineinander geschachtelten Skulpturleisten, dem Vorhandensein labialer Foramina sowie dem häufigen Auftreten einer größeren lingualen Öffnung an der Zahnbasis, dem Durchtritt eines zentralen Nährkanals. Die Bransonelliformes stellen die ursprünglichere Schwestergruppe zu den Xenacanthiformes innerhalb der Xenacanthimorpha dar. doi:10.1002/mmng.200700005

  8. Uso de marcas convencionales en un país con escasa experiencia en marcación de peces marinos

    Directory of Open Access Journals (Sweden)

    Marcelo Pérez

    2014-03-01

    Full Text Available La utilización del marcado mediante distintas técnicas ha sido reconocida como un valioso medio para estudiar distintos aspectos poblacionales de especies de peces marinos. El Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP de Argentina, diseñó una actividad para la utilización de la técnica de marcado y recaptura mediante marcas convencionales en un tiburón demersal-bentónico "gatuzo" (Mustelus schmitti, para establecer desplazamientos de la especie en el Ecosistema Costero Argentino Uruguayo. Se estableció el uso de marcas convencionales principalmente por ser un método económico, utilizado en tiburones en todo el mundo, aunque dependiente de la actividad de la flota comercial. Entre noviembre de 2010 y diciembre de 2011, se marcaron 2471 ejemplares mayores de 50 cm de longitud total, mediante marcas tipo DART. Hasta diciembre de 2012 se recuperaron 42 marcas (1,70%. Este trabajo tiene como objetivo describir, discutir y analizar algunos problemas asociados a la marcación y recuperación de marcas convencionales en Argentina, país casi sin experiencia en esta técnica en peces marinos, mediante la aplicación a esta especie de tiburón.

  9. A taxonomic revision of the seed-harvester ant genus Pogonomyrmex (Hymenoptera: Formicidae) on Hispaniola.

    Science.gov (United States)

    Johnson, Robert A; Cover, Stefan P

    2015-06-11

    We revise species of seed-harvester ants in the genus Pogonomyrmex (subfamily Myrmicinae) that occur on the Caribbean island of Hispaniola. Three species are recognized: P. aterrimus Wheeler (new status), P. saucius Wheeler and Mann, and P. schmitti Forel. Pogonomyrmex schmitti sublaevigatus Wheeler (= schmitti) and P. schmitti darlingtoni Wheeler (= aterrimus) are synonomized. We also describe the queen of P. aterrimus and P. saucius, and provide information on biology, distribution maps, and a key to workers and queens.

  10. Empleo del Polvo de Spirulina Platensis en la Alimentacion de Zoeas y Mysis de Litopenaeus schmitti (Perez-Farfante y Kensley, 1997)

    OpenAIRE

    Civera Cerecedo, R.; Villareal, H.; Gaxiola Cortes, G.; Jaime Ceballos, B.; García Galano, T.

    2004-01-01

    En los laboratorios de producción de postlarvas de camarón se suministra, en los estadios de protozoea y mysis, alimento vivo para garantizar buenos resultados en el cultivo sin embargo, el empleo de alimentos artificiales posibilita reducir la costosa dependencia de las algas y los quistes de Artemia ( Wouters et al, 2004). Aunque los resultados alcanzados con diferentes dietas artificiales en el cultivo larval son satisfactorios, aún existe gran preferencia por la utilización del a...

  11. Occurrence of Hydrolagus macrophthalmus (Chondrichthyes: Holocephali: Chimaeridae in the northeastern Pacific Presencia de Hydrolagus macrophthalmus (Chondrichthyes: Holocephali: Chimaeridae en el Pacífico nororiental

    Directory of Open Access Journals (Sweden)

    Adrián F. González-Acosta

    2010-04-01

    Full Text Available The southeastern Pacific chimaeroid Hydrolagus macrophthalmus De Buen, 1959, is reported for the first time in the northeastern Pacific on the basis of 1 male specimen (945 mm TL caught on 13 April 1995 off Manzanillo, Colima (Mexico: 18° 30'N, 104° 15'W at the surface above deep water (2 000 m. The first occurrence of this species increases the number of chimaeroid species known in the northeastern Pacific and expands their known range.Se registra por primera vez la presencia de la quimera Hydrolagus macrophthalmus De Buen, 1959, en aguas del Pacífico nororiental; especie cuya distribución se consideraba como exclusiva del Pacífico sur oriental. El 13 de abril de 1995, se recolectó 1 ejemplar macho (945 mm TL en la superficie del mar frente a Manzanillo, Colima (México: 18° 30'N, 104° 15'O, en una zona de gran profundidad (2 000 m. Su presencia, incrementa el número de quimeras del Pacífico nororiental y asimismo, amplía su distribución hacia el hemisferio norte.

  12. Shark tales: a molecular species-level phylogeny of sharks (Selachimorpha, Chondrichthyes).

    Science.gov (United States)

    Vélez-Zuazo, Ximena; Agnarsson, Ingi

    2011-02-01

    Sharks are a diverse and ecologically important group, including some of the ocean's largest predatory animals. Sharks are also commercially important, with many species suffering overexploitation and facing extinction. However, despite a long evolutionary history, commercial, and conservation importance, phylogenetic relationships within the sharks are poorly understood. To date, most studies have either focused on smaller clades within sharks, or sampled taxa sparsely across the group. A more detailed species-level phylogeny will offer further insights into shark taxonomy, provide a tool for comparative analyses, as well as facilitating phylogenetic estimates of conservation priorities. We used four mitochondrial and one nuclear gene to investigate the phylogenetic relationships of 229 species (all eight Orders and 31 families) of sharks, more than quadrupling the number of taxon sampled in any prior study. The resulting Bayesian phylogenetic hypothesis agrees with prior studies on the major relationships of the sharks phylogeny; however, on those relationships that have proven more controversial, it differs in several aspects from the most recent molecular studies. The phylogeny supports the division of sharks into two major groups, the Galeomorphii and Squalimorphii, rejecting the hypnosqualean hypothesis that places batoids within sharks. Within the squalimorphs the orders Hexanchiformes, Squatiniformes, Squaliformes, and Pristiophoriformes are broadly monophyletic, with minor exceptions apparently due to missing data. Similarly, within Galeomorphs, the orders Heterodontiformes, Lamniformes, Carcharhiniformes, and Orectolobiformes are broadly monophyletic, with a couple of species 'misplaced'. In contrast, many of the currently recognized shark families are not monophyletic according to our results. Our phylogeny offers some of the first clarification of the relationships among families of the order Squaliformes, a group that has thus far received relatively little phylogenetic attention. Our results suggest that the genus Echinorhinus is not a squaliform, but rather related to the saw sharks, a hypothesis that might be supported by both groups sharing 'spiny' snouts. In sum, our results offer the most detailed species-level phylogeny of sharks to date and a tool for comparative analyses.

  13. Revision of the Xenacanthida (Chondrichthyes : Elasmobranchii) from the Carboniferous of the British Isles

    Energy Technology Data Exchange (ETDEWEB)

    Hampe, O. [Humboldt University, Berlin (Germany)

    2003-07-01

    Xenacanthids were a very successful group of elasmobranchs that ranged from the Lower Carboniferous to the Upper Triassic. The history of discovery of the xenacanthids, which is closely connected with the history of coal prospecting in England, began with the finding of the type specimen of Xenacanthus laevissimus in the Westphalian B of the West Midlands. In this first review of British Carboniferous xenacanthids, the number of taxa, mainly erected during Victorian times, is reduced to 14 species distributed among six genera. Determinable remains are recorded from at least 96 localities in the British Isles. Unique characteristics of the Dinantian Diplodoselache suggest that the lineage to which this taxon belongs marks a dead end in xenacanthid evolution. This investigation also shows that the Pendleian Dicentrodus, formerly described as Cladodus, belongs to the xenacanthids. The occurrence of Orthacanthus cf. kounoviensis in the Pennines, also known from the German Saar-Nahe basin, the Saale depression and from Bohemia, indicates a faunal exchange between these intramontainous basins during the Carboniferous. The genus Triodus is identified from British deposits for the first time. A cladistic analysis of the xenacanthids suggests that they evolved from phoebodontid elasmobranchs. This analysis also confirms separation of the Middle Devonian Antarctilamna from a relationship with xenacanthid sharks.

  14. The complete mitochondrial genome of the basking shark Cetorhinus maximus (Chondrichthyes, Cetorhinidae).

    Science.gov (United States)

    Hester, Jennifer; Atwater, Kimberly; Bernard, Andrea; Francis, Malcolm; Shivji, Mahmood S

    2015-01-01

    The basking shark (Cetorhinus maximus) is the world's second largest fish and the subject of strong conservation concern. Minimal genetic assessment exists for this globally distributed but regionally endangered species. We describe the complete mitochondrial genome sequence of C. maximus, obtained via polymerase chain reaction-based Sanger sequencing. The total length of the mitogenome is 16,670 bp and consists of 2 rRNAs, 22 tRNAs and 13 protein-coding genes. The base composition has an A + T bias (63.6%), as is often seen in other sharks. Gene order is equivalent to that found in most vertebrates.

  15. Ampullary sense organs, peripheral, central and behavioral electroreception in chimeras (Hydrolagus, Holocephali, Chondrichthyes).

    Science.gov (United States)

    Fields, R D; Bullock, T H; Lange, G D

    1993-01-01

    Ampullary sense organs are distributed in groups over the head of Hydrolagus colliei with their pores in clusters and innervated by the buccal, hyomandibular and superficial ophthalmic branches of the anterior lateral line nerve. The ampullae contain ciliated sense cells in an alveolate-shaped epithelium, which communicates to the surface through a jelly-filled tube. The sense cells synapse at their bases with the afferent nerve fibers that terminate in the dorsal nucleus of the anterior lateral line lobe of the medulla. The anatomy and ultrastructure support the homology with the ampullae of Lorenzini of elasmobranchs. Single units recorded from the buccal branch of the anterior lateral line nerve are either lateral line or ampullary in character, the former being sensitive only to mechanical stimuli, the latter to both mechanical and to weak electric stimuli. They are also distinguished by the positions of their receptive fields. The electroreceptive units are spontaneously active and are excited by a cathode placed near the opening of their pore and inhibited by an anode. Compound evoked potentials are recorded from beneath the lateral aspect of the tectum in response to weak electric fields in the bath. Each recording locus has a best position and orientation of the electric field. The electric fields are effective if their duration is longer than ca. 2 ms; longer than 10 ms makes no difference until an OFF effect becomes distinct at ca. 50 ms. The reception is tuned to low frequencies but is not sensitive to maintained current (DC). Evoked potentials summating moderate numbers of responses are clear at electroreception, similar to that in elasmobranchs and most other groups of nonteleost fishes, except for Myxini and Neopterygii (holosteans), is present in the subclass Holocephali. The notion is supported that this modality and its central as well as peripheral apparatus arose early in the evolution of vertebrates. Only two losses of the whole system need be hypothesized, on this idea, once in the ancestors of the hagfishes and once in the ancestors of the neopterygians, which include the teleosts. Some orders of teleosts then evolved a new system of electroreception independently. The ciliary receptor cells are probably primitive; microvillar sense cells evolved independently.

  16. Sexually Dimorphic Morphological Characters in Five North Atlantic Deepwater Skates (Chondrichthyes: Rajiformes

    Directory of Open Access Journals (Sweden)

    Alexei M. Orlov

    2011-01-01

    Full Text Available Skates exhibit a variety of manifestations of sexual dimorphism. However, this phenomenon has been poorly documented in deepwater species. New data on the sexual dimorphism of five species of deepwater skates from the North Atlantic Ocean are presented: Amblyraja jenseni, Bathyraja pallida, Bathyraja richardsoni, Rajella bigelowi, and R. kukujevi. These skates exhibit sexual dimorphism most frequently in interorbital width, disc length and width, length of the third gill slit, horizontal diameter of the orbit, length of the fifth gill slit, space between the first and fifth gill slits, length of the second dorsal fin base, mouth width, length and width of each lobe of the nasal curtain, distance from the snout to the center of anus, distance from the snout tip to the point of maximum disc width, length of the lateral fold, length of the orbit + spiracle (measured together, tail height at the pelvic fin tips, and the number of median thorns.

  17. Diversity and biogeographic affinities of sharks, rays and chimaeras (Chondrichthyes: Elasmobranchii, Holocephali) of Mexico

    OpenAIRE

    DEL MORAL FLORES, LUIS FERNANDO; Morrone,Juan J.; Javier ALCOCER; Pérez-Ponce de León, Gerardo

    2016-01-01

    A pesar de la gran importancia ecológica, evolutiva y económica de los condrictios, su diversidad ha sido escasamente estudiada en México. En este estudio se describe la diversidad de especies de condrictios que se han registrado hasta el momento para México, la cual se compone de 214 especies (111 tiburones, 95 rayas y 8 quimeras) y representa el 17.3 % de las registradas a nivel mundial. Las familias con mayor diversidad de especies son Rajidae (14.5 %), Carcharhinidae (12.1 %), Pentanchida...

  18. Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes.

    Directory of Open Access Journals (Sweden)

    Charlie J Underwood

    Full Text Available Shark and ray (elasmobranch dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays, hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files, presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the general plesiomorphic vertebrate dental condition.

  19. Dentitions of Barbclabornia (new genus, Chondrichthyes: Xenacanthiformes from the Upper Palaeozoic of North America

    Directory of Open Access Journals (Sweden)

    G. D. Johnson

    2003-01-01

    Full Text Available Barbclabornia luedersensis (Berman, 1970 is defined on the basis of small (2 mm high isolated teeth that lack an intermediate cusp. It is known from the Lower Permian and possibly the Upper Pennsylvanian of North America. The two principal cusps are slightly curved orally, nearly parallel, and bear cristae mainly on their distal halves. They are cylindrical but become compressed proximally. The long axis of each cusp base is >45° to the labial margin of the tooth base. The base bears a prominent apical button in contact with the cusps; a central foramen is absent. Fewer than ten foramina occur on the aboral surface of the base, which bears a prominent concave basal tubercle. The shape of the base ranges from somewhat triangular to quadrangular. The cusps are composed of orthodentine covered by hypermineralized pallial dentine; the base is composed of orthodentine but may also contain trabecular dentine. Except for the possible occurrence of symphysial teeth, the dentition is homodont. Barbclabornia cf. B. luedersensis is stratigraphically highest in the known range of the genus and is restricted to the nearly lowermost part of the Clear Fork Group (Artinskian of Texas. The teeth are similar to B. luedersensis, but are more robust and have a quadrangular-shaped base. Barbclabornia was large, based on an undescribed palatoquadrate some 45 cm long. It was probably freshwater and is most closely related to Triodus. Barbclabornia luedersensis (Berman, 1970 wird anhand kleiner (2 mm Höhe, isolierter Zähne definiert, denen eine Medianspitze fehlt. Die Art ist aus dem unteren Perm und möglicherweise dem oberen Pennsylvanium von Nordamerika bekannt. Die zwei Hauptspitzen sind schwach oral geneigt, beinahe parallel und zeigen hauptsächlich auf der distalen Hälfte Cristae. Die Spitzen sind zylindrisch, erhalten allerdings proximal durch Kompression einen ovalen Umriss. Der Winkel zwischen der Längsachse jeder Spitze und dem labialen Rand der Zahnbasis beträgt mehr als 45°. Die Basis besitzt einen prominenten, in Kontakt mit den Spitzen stehenden Apicalhöcker, ein zentrales Foramen fehlt. Weniger als zehn Foramina sowie ein prominenter, konkav eingebuchteter Basaltuberkel befinden sich auf der aboralen Seite der Basis. Die Basis zeigt einen etwa tri- bis quadrangulären Umriss. Die Spitzen bestehen aus Orthodentin, ummantelt von einem hypermineralisierten Pallialdentin; die Basis besteht aus Orthodentin, kann aber auch Trabeculardentin beinhalten. Mit Ausnahme des Auftretens von Symphysenzähnen ist die Bezahnung homodent. Barbclabornia cf. B. luedersensis repräsentiert den stratigraphisch jüngsten Vertreter dieser Gattung und ist etwa auf den untersten Abschnitt der Clear Fork Group (Artinskium von Texas beschränkt. Die Zähne ähneln denen des B. luedersensis, sind aber robuster und besitzen eine Basis mit quadrangulärem Umriss. Ein unbeschriebenes Palatoquadratum von etwa 45 cm Länge weist Barbclabornia als großwüchsig aus. Es handelt sich wahrscheinlich um eine Süßwasserform. Barbclabornia besitzt enge Beziehungen zu Triodus. doi:10.1002/mmng.20030060106

  20. Hematological parameters in shortnose guitarfish Zapteryx brevirostris Müller and Henle, 1841 (Chondrichthyes, Rhinobatidae

    Directory of Open Access Journals (Sweden)

    Nathalia Barreto B.

    2015-12-01

    Full Text Available Objective. In view of the deficiency of information in the area of clinical pathology of elasmobranchs, mainly of the physiological parameters, the aim of this work was to study hematological parameters of the Zapteryx brevirostris species. Materials and methods. Four specimens apparently healthy of Zapteryx brevirostris; three females and a male were used. These animals are all pertaining ones to the Aquarium of Ubatuba, São Paulo (Brazil. Results. The obtained average of hematological values for the Zapteryx brevirostris were: Red Blood Cells were - 0.96 x 106/μL, Packed Cell Volume - 24.3% and White Blood Cells - 36.8 x 103/μL. Conclusion. Although the small N, which decreases the accuracy, this research has scientific value because the situation of vulnerability of Zapteryx brevirostris, suggesting other studies.

  1. Zob paleozojskega morskega psa rodu Glikmanius (Chondrichthyes, Ctenacanthidae iz Karavank (Slovenija

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    Matija Križnar

    2015-07-01

    Full Text Available Upper Paleozoic beds of Karavanke Mountains are rich in invertebrate and plant fossils, while the remains of vertebrates are extremely rare. A new cladodont shark tooth was found in Lower Permian beds near Hru{ica, at the locality named Na Visokih. We have identified the tooth as belonging to species Glikmanius cf. occidentalis (Leidy. This is the first find of this species in the southern Europe.

  2. Morphological and taxonomic revision of species of Squatina from the Southwestern Atlantic Ocean (Chondrichthyes: Squatiniformes: Squatinidae).

    Science.gov (United States)

    Vaz, Diego F B; De Carvalho, Marcelo R

    2013-01-01

    The morphology and taxonomy of species of Squatina from the southwestern Atlantic Ocean are revised. Species previously considered valid, Squatina argentina (Marini, 1930), Squatina guggenheim Marini, 1936 and Squatina occulta Vooren and da Silva, 1991, are investigated and described in detail, including a morphometric and meristic study of specimens from their recorded range. The taxonomic status of the doubtful nominal species Squatina punctata Marini, 1936 was also evaluated. This species was previously considered a junior synonym of S. argentina, a junior synonym of S. guggenheim, or a senior synonym of S. occulta. Although there is much morphological similarity between Squatina species, significant differences in dermal denticle patterns, dorsal coloration, tooth formula, and size at maturity are reported, enabling the recognition of S. argentina, S. guggenheim and S. occulta as valid species, and relegating S. punctata to the synonymy of S. guggenheim. Differences in skeletal morphology between valid species are described and considered supportive of the taxonomic hypothesis, corroborating a previous study of neurocrania. Additionally, an unidentified specimen is reported, as Squatina sp., from the continental shelf of Bahia state, Brazil, recognized by having more vertebral centra and a conspicuous dermal denticle morphology on interspiracular region, features not present in other South America angelshark species. A report on the only known syntype of Squatina dumeril Le Sueur, 1818 is presented, describing features that are still preserved and designating it as lectotype. Lateral-line sensory canals, skeleton, and cranial and hypobranchial muscles for the three valid species of Squatina from the southwestern Atlantic, as well as the brain and cranial nerves of S. guggenheim, are described and illustrated.

  3. Ontogenetic Shifts in Brain Organization in the Bluespotted Stingray Neotrygon kuhlii (Chondrichthyes: Dasyatidae).

    Science.gov (United States)

    Lisney, Thomas J; Yopak, Kara E; Camilieri-Asch, Victoria; Collin, Shaun P

    2017-02-28

    Fishes exhibit lifelong neurogenesis and continual brain growth. One consequence of this continual growth is that the nervous system has the potential to respond with enhanced plasticity to changes in ecological conditions that occur during ontogeny. The life histories of many teleost fishes are composed of a series of distinct stages that are characterized by shifts in diet, habitat, and behavior. In many cases, these shifts correlate with changes in overall brain growth and brain organization, possibly reflecting the relative importance of different senses and locomotor performance imposed by the new ecological niches they encounter throughout life. Chondrichthyan (cartilaginous) fishes also undergo ontogenetic shifts in habitat, movement patterns, diet, and behavior, but very little is known about any corresponding shifts in the size and organization of their brains. Here, we investigated postparturition ontogenetic changes in brain-body size scaling, the allometric scaling of seven major brain areas (olfactory bulbs, telencephalon, diencephalon, optic tectum, tegmentum, cerebellum, and medulla oblongata) relative to the rest of the brain, and cerebellar foliation in a chondrichthyan, i.e., the bluespotted stingray Neotrygon kuhlii. We also investigated the unusual morphological asymmetry of the cerebellum in this and other batoids. As in teleosts, the brain continues to grow throughout life, with a period of rapid initial growth relative to body size, before slowing considerably at the onset of sexual maturity. The olfactory bulbs and the cerebellum scale with positive allometry relative to the rest of the brain, whereas the other five brain areas scale with varying degrees of negative allometry. None of the major brain areas showed the stage-specific differences in rates of growth often found in teleosts. Cerebellar foliation also increases at a faster rate than overall brain growth. We speculate that changes in the olfactory bulbs and cerebellum could reflect increased olfactory and locomotor capabilities, which may be associated with ontogenetic shifts in diet, habitat use, and activity patterns, as well as shifts in behavior that occur with the onset of sexual maturity. The frequency distributions of the three cerebellar morphologies exhibited in this species best fit a 2:1:1 (right-sided:left-sided:intermediate) distribution, mirroring previous findings for another stingray species.

  4. Further comment on the nomenclature of the freshwater stingray Elipesurus spinicauda Schomburgk, 1843 (Chondrichthyes: Potamotrygonidae

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    Ricardo S. Rosa

    1985-01-01

    Full Text Available The monotypic genus Elipesurus of neotropical freshwater stingrays, and its type species E. spinicauda, are known from a single specimen which lacked a developed tail and caudal sting. No type or similar specimens exist. The original description and illustration are inaccurate, without diagnostic measurements or characters, excepting those mentioned above. Therefore, a precise identification of E. spinicauda remains impòssible, and both names are considered doubtful. Since all other potamotrygonid stingrays have more or less developed tails and stings, the Elipesurus condition is regarded as a mutilation.

  5. Potamotrygon boesemani (Chondrichthyes: Myliobatiformes: Potamotrygonidae, a new species of Neotropical freshwater stingray from Surinam

    Directory of Open Access Journals (Sweden)

    Ricardo S. Rosa

    Full Text Available Potamotrygon boesemani, new species, is described from the Corantijn river drainage in Surinam. The species has a diagnostic dorsal color pattern formed by deep orange to red ocellated spots of irregular form, encircled by relatively broad black rings. Potamotrygon boesemani is distinguished from other ocellated congeners (P. motoro, P. henlei and P. leopoldi by the more intensely colored ocelli, which are usually yellow in the latter species. From P. motoro it is also distinguished by the darker dorsal background coloration, by the broader black contour of the dorsal ocelli, and by the irregular form of the ocelli as compared to the more rounded shape in the latter species. From P. henlei and P. leopoldi, it is distinguished by the lack of ocelli on tail. From the tentatively identified specimen of P. ocellata, which also has dark orange ocelli, the irregular contour of the ocelli in the new species is also distinctive. The teeth are relatively smaller and in greater number than in P. motoro and P. ocellata, with up to 45 rows in the upper jaw.

  6. The use of pelvic fins for benthic locomotion during foraging behavior in Potamotrygon motoro (Chondrichthyes: Potamotrygonidae

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    Akemi Shibuya

    2015-06-01

    Full Text Available Synchronized bipedal movements of the pelvic fins provide propulsion (punting during displacement on the substrate in batoids with benthic locomotion. In skates (Rajidae this mechanism is mainly generated by the crural cartilages. Although lacking these anatomical structures, some stingray species show modifications of their pelvic fins to aid in benthic locomotion. This study describes the use of the pelvic fins for locomotory performance and body re-orientation in the freshwater stingray Potamotrygon motoro (Müller & Henle, 1841 during foraging. Pelvic fin movements of juvenile individuals of P. motoro were recorded in ventral view by a high-speed camera at 250-500 fields/s-1. Potamotrygon motoro presented synchronous, alternating and unilateral movements of the pelvic fins, similar to those reported in skates. Synchronous movements were employed during straightforward motion for pushing the body off the substrate as well as for strike feeding, whereas unilateral movements were used to maneuver the body to the right or left during both locomotion and prey capture. Alternating movements of the pelvic fins are similar to bipedal movements in terrestrial and semi-aquatic tetrapods. The pelvic fins showed coordinated movements during feeding even when stationary, indicating that they have an important function in maintaining body posture (station holding during prey capture and manipulation. The use of pelvic fins during prey stalking may be advantageous because it results in less substrate disturbance when compared to movements generated by pectoral fin undulation. The range of pelvic fin movements indicates more complex control and coordination of the pelvic radial muscles.

  7. Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes).

    Science.gov (United States)

    Underwood, Charlie J; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J; Fraser, Gareth J; Smith, Moya Meredith

    2015-01-01

    Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the general plesiomorphic vertebrate dental condition.

  8. Historical and contemporary records of the angular rough shark Oxynotus centrina (Chondrichthyes; Oxynotidae in Turkish waters

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    H. KABASAKAL

    2012-12-01

    Full Text Available During the last 58 years, only 12 angular rough sharks were recorded in Turkish waters. Rare captures of the species in the area needs an immediate action for the conservation of O. centrina. To protect the habitat of O. centrina, strict regulations should be implemented for diving in the localities, where the angular rough sharks occur regularly. Protecting the habitat of the angular rough shark is an urgent need before subjecting O. centrina to 100% protection in the seas of Turkey.

  9. New data on Upper Devonian stratigraphy of the northwestern Kuznetsk basin: Evidence from foraminifera and chondrichthyes

    Science.gov (United States)

    Timokhina, I. G.; Rodina, O. A.

    2015-09-01

    The thorough investigation of four Frasnian-Famennian (Upper Devonian) boundary sections along the right side of the Tom River northwest of Kemerovo yielded new data on the composition of their foraminiferal and ichthyofaunal assemblages. These data were used for development of the zonal foraminiferal scale for Upper Devonian deposits of the northwestern Kuznetsk coal basin and the first zonal scale for their subdivision on the basis of Elasmobranchii remains and for correlation of the examined sections between each other and with Upper Devonian sequences in other regions. The analysis of foraminiferal and ichthyofaunal assemblages, which are the most widespread in upper Frasnian sections of the northwestern Kuznetsk coal basin, made it possible to specify the regional stratigraphic model.

  10. Mandibular and hyoid muscles of Galeomorph sharks (Chondrichthyes: Elasmobranchii), with remarks on their phylogenetic intrarelationships.

    Science.gov (United States)

    Soares, Mateus C; de Carvalho, Marcelo R

    2013-10-01

    The superorder Galeomorph comprises the orders Heterodontiformes, Orectolobiformes, Lamniformes, and Carcharhiniformes. Recent morphological and molecular support that it is a monophyletic taxon. The phyletic relationship within the Galeomorphi are also well resolved. However, only few morphological characters of the mandibular and hyoid muscles have been employed, and a detailed description of these muscles and their variations may contribute new interpretations of homology and to the discussion of different hypothesis of intrarelationships. This paper provides a detailed description of mandibular and hyoid arch muscles in galeomorph sharks, within a comparative elasmobranch framework, with the objective to discuss putative homologies that may elucidate our understanding of galeomorph evolution. Twenty-eight galeomorph species were dissected, described, illustrated and compared with other elasmobranchs and with data from the literature. The Galeomorphi are supported as monophyletic by presenting the m. levator labii superioris attached directly to the neurocranium, different from the attachment through a tendon in basal squalomorphs. Heterodontiformes and Orectolobiformes share particular variations in the position and insertion of the m. levator labii superioris and the presence of a well-defined m. levator hyomandibulae. Lamniformes and Carcharhiniformes show similar patterns in the position and attachment of the m. levator labii superioris, subdivision of the m. adductor mandibulae, and the presence of an almost indivisible m. levator hyomandibulae and m. constrictor hyoideus dorsalis, similar to the condition, albeit independently, in basal squalomorphs. No specific mandibular or hyoid arch muscle character was found to support the clade composed of Orectolobiformes, Lamniformes, and Carcharhiniformes, as advocated by recent phylogenetic analyses.

  11. A dorsal fold in Gymnura micrura (Bloch and Scheneider, 1801 (Chondrichthyes: Gymnuridae

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    Jorge Luiz Silva Nunes

    2009-04-01

    Full Text Available This paper reports a dorsal fold which is a membranous structure located on the tail of two juvenile butterfly rays, Gymnura micrura (Bloch & Scheneider, 1801, caught through artisanal fishery in the shallow waters of Maranhão State (Brazil.Neste manuscrito registra-se uma nadadeira dorsal em dois espécimes juvenis de Gymnura micrura (Bloch and Scheneider, 1801 capturadas pela pesca artesanal em águas rasas do estado do Maranhão (Brasil.

  12. Morphological description of Dipturus mennii (Chondrichthyes: Elasmobranchii: Rajidae and its differentiation from Dipturus trachyderma

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    Renan A Moreira

    2011-02-01

    Full Text Available Squamation patterns and skeletal anatomy (neurocranium, visceral arches, synarcual cartilage, scapulocoracoid, puboischiadic bar, and mixopterigium of Dipturus mennii Gomes & Paragó, 2001 are described as a contribution to our limited knowledge of the anatomy of species of Dipturus Rafinesque, 1810. The hyoid and branchial arches, as well as the synarcual cartilage, are described for the first time in this species. We provide morphological comparisons of this species with Dipturus trachyderma (Krefft & Stehmann, 1975, a species that may be confused with D. mennii; we further corroborate, through anatomical features, that these species warrant separate taxonomic recognition. The main differences between D. mennii and D. trachyderma were found in squamation of the nuchal and middisc region, neurocranium, pectoral girdle, and principally the clasper skeleton. The morphology of the pelvic girdle is similar in both species. Dipturus is characterized by having the ventral terminal cartilage J-shaped (as opposed to the Z-shaped ventral terminal cartilage in Zearaja, whose species were, until recently, placed in Dipturus. Additional characters that may be derived for Dipturus include the anterior rostral groove and elevated rostral proportions

  13. Evolutionary origins and development of saw-teeth on the sawfish and sawshark rostrum (Elasmobranchii; Chondrichthyes).

    Science.gov (United States)

    Welten, Monique; Smith, Moya Meredith; Underwood, Charlie; Johanson, Zerina

    2015-09-01

    A well-known characteristic of chondrichthyans (e.g. sharks, rays) is their covering of external skin denticles (placoid scales), but less well understood is the wide morphological diversity that these skin denticles can show. Some of the more unusual of these are the tooth-like structures associated with the elongate cartilaginous rostrum 'saw' in three chondrichthyan groups: Pristiophoridae (sawsharks; Selachii), Pristidae (sawfish; Batoidea) and the fossil Sclerorhynchoidea (Batoidea). Comparative topographic and developmental studies of the 'saw-teeth' were undertaken in adults and embryos of these groups, by means of three-dimensional-rendered volumes from X-ray computed tomography. This provided data on development and relative arrangement in embryos, with regenerative replacement in adults. Saw-teeth are morphologically similar on the rostra of the Pristiophoridae and the Sclerorhynchoidea, with the same replacement modes, despite the lack of a close phylogenetic relationship. In both, tooth-like structures develop under the skin of the embryos, aligned with the rostrum surface, before rotating into lateral position and then attaching through a pedicel to the rostrum cartilage. As well, saw-teeth are replaced and added to as space becomes available. By contrast, saw-teeth in Pristidae insert into sockets in the rostrum cartilage, growing continuously and are not replaced. Despite superficial similarity to oral tooth developmental organization, saw-tooth spatial initiation arrangement is associated with rostrum growth. Replacement is space-dependent and more comparable to that of dermal skin denticles. We suggest these saw-teeth represent modified dermal denticles and lack the 'many-for-one' replacement characteristic of elasmobranch oral dentitions.

  14. Decreasing urea∶trimethylamine N-oxide ratios with depth in chondrichthyes: a physiological depth limit?

    Science.gov (United States)

    Laxson, Carrie J; Condon, Nicole E; Drazen, Jeffrey C; Yancey, Paul H

    2011-01-01

    In marine osmoconformers, cells use organic osmolytes to maintain osmotic balance with seawater. High levels of urea are utilized in chondrichthyans (sharks, rays, skates, and chimaeras) for this purpose. Because of urea's perturbing nature, cells also accumulate counteracting methylamines, such as trimethylamine N-oxide (TMAO), at about a 2∶1 urea∶methylamine ratio, the most thermodynamically favorable mixture for protein stabilization, in shallow species. However, previous work on deep-sea teleosts (15 species) and chondrichthyans (three species) found an increase in muscle TMAO content and a decrease in urea content in chondrichthyans with depth. We hypothesized that TMAO counteracts protein destabilization resulting from hydrostatic pressure, as is demonstrated in vitro. Chondrichthyans are almost absent below 3,000 m, and we hypothesized that a limitation in urea excretion and/or TMAO retention might play a role. To test this, we measured the content of major organic osmolytes in white muscle of 13 chondrichthyan species caught with along-contour trawls at depths of 50-3,000 m; the deepest species caught was from 2,165 m. Urea and TMAO contents changed significantly with depth, with urea∶TMAO declining from 2.96 in the shallowest (50-90 m) groups to 0.67 in the deepest (1,911-2,165 m) groups. Urea content was 291-371 mmol/kg in the shallowest group and 170-189 mmol/kg in the deepest group, declining linearly with depth and showing no plateau. TMAO content was 85-168 mmol/kg in the shallowest group and 250-289 mmol/kg in the deepest groups. With data from a previous study for a skate at 2,850 m included, a second-order polynomial fit suggested a plateau at the greatest depths. When data for skates (Rajidae) were analyzed separately, a sigmoidal fit was suggested. Thus, the deepest chondrichthyans may be unable to accumulate sufficient TMAO to counteract pressure; however, deeper-living specimens are needed to fully test this hypothesis.

  15. Reproductive biology of Zearaja chilensis (Chondrichthyes: Rajidae) in the south-east Pacific Ocean.

    Science.gov (United States)

    Bustamante, C; Vargas-Caro, C; Oddone, M C; Concha, F; Flores, H; Lamilla, J; Bennett, M B

    2012-04-01

    Between 2000 and 2002, three artisanal landing sites were sampled in southern Chile, with data on population structure and reproductive development collected from 5477 yellownose skates Zearaja chilensis. Total length (L(T) ) ranged from 33 to 158 cm for females and 34 to 155 cm for males. No sexual dimorphism was evident in disc size (length or width) or in L(T)-mass relationships. The smallest mature female was 95 cm L(T) and the size at which 50% were mature (L(T50) ) was 109 cm. Males matured between 80 and 90 cm L(T) with a L(T50) of 88 cm. Although the largest Z. chilensis captured by the artisanal fishery was 155 cm L(T) , 89% of landings comprised relatively small, immature fish. This situation may compromise the stock integrity if intrinsic vulnerability and probable long-life span of Z. chilensis are considered. Consequences for the survival of the species and possible signs of a fishery collapse must be reviewed by management authorities by consideration of both artisanal and industrial landings in Chile.

  16. Morphological description of Dipturus mennii (Chondrichthyes: Elasmobranchii: Rajidae) and its differentiation from Dipturus trachyderma

    OpenAIRE

    Moreira,Renan A; Gomes,Ulisses L.; Marcelo R. de Carvalho

    2011-01-01

    Squamation patterns and skeletal anatomy (neurocranium, visceral arches, synarcual cartilage, scapulocoracoid, puboischiadic bar, and mixopterigium) of Dipturus mennii Gomes & Paragó, 2001 are described as a contribution to our limited knowledge of the anatomy of species of Dipturus Rafinesque, 1810. The hyoid and branchial arches, as well as the synarcual cartilage, are described for the first time in this species. We provide morphological comparisons of this species with Dipturus trachy...

  17. The complete mitochondrial genome of the rayfish Raja porosa (Chondrichthyes, Rajidae).

    Science.gov (United States)

    Kim, Il-Chan; Jung, Sang-Oun; Lee, Young-Mi; Lee, Chang Joo; Park, Joong-Ki; Lee, Jae-Seong

    2005-06-01

    We isolated mitochondrial DNA from the rayfish Raja porosa by long-polymerase chain reaction (Long-PCR) with conserved primers, and sequenced it by primer walking method using flanking sequences as sequencing primers. R. porosa mitochondrial DNA consists of 16,972 bp and its structural organization is conserved in comparison with other fishes and mammals. Based on the mitochondrial cytochrome b (cyt b) sequence, the phylogenetic position of R. porosa among cartilaginous fishes was inferred using different phylogenetic methods (ML-based quartet puzzling, Neighbor-joining (NJ) and Bayesian approaches). In this paper, we report the characteristics of the R. porosa mitochondrial genome including structural organization, base composition of rRNAs, tRNAs and protein-encoding genes and characteristics of mitochondrial tRNAs. These findings are applicable to comparative mitogenomics of R. porosa with other related taxa.

  18. Morphology and dynamics of male gametogenesis in Sympterygia bonapartii (Chondrichthyes, Rajidae from Northern Patagonia

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    Ana C. Moya

    2015-09-01

    Full Text Available ABSTRACT The smallnose fanskate, Sympterygia bonapartii Müller & Henle, 1841 is one of the most disembarked items in commercial harbors in Argentina. In this work, the microscopic architecture of mature male gonads and the dynamics of cysts development are analyzed as a contribution to awareness of the reproductive biology of the species. Some biological data related to reproduction are given as well. Two seasons were sampled (fall and spring and length classes's frequency distribution and maturity stages frequency distribution are given. Size at first sexual maturation for males was estimated at 57 cm of total length. Testes are symmetric, peer, lobed, with several germinal zones. Inside the gonads, there are many spermatocysts, containing reproductive cells at the same developmental stage. On the basis of their cytological and microanatomical features, several maturative degrees of the spermatogenic series were differentiated. Few Leydig cells were recognized at the interstitial tissue among cysts. The microscopic and semiquantitative analysis performed in this work provides morphological information about male gametogenesis and some biological data for the North Patagonian population of this economically and ecologically important species.

  19. From coexistence to competitive exclusion: can overfishing change the outcome of competition in skates (Chondrichthyes, Rajidae?

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    Natalia L Ruocco

    2012-03-01

    Full Text Available Competition for food could be a major force driving changes in the community structure of skates (Rajidae subjected to fishing exploitation. Under this hypothesis, small skates are released from competition with larger skates after fishing has depleted the larger species. Here, we compare the abundance patterns of two sympatric skates with similar niches but different life histories, Bathyraja albomaculata (larger and slow-reproducing and Bathyraja macloviana (smaller and faster-reproducing, before (1971, 1978 and after (1998-2004 a 108% increase in industrial bottom trawling on the southeastern South American shelf in order to test the prediction that B. macloviana should competitively exclude B. albomaculata after the increase in fishing mortality. In 1971 and 1978, there was no relationship between the abundance of both species, indicating that they coexisted over large scales. In 1998-2004, the relationship between the abundances of these skates was bell-shaped, indicating that both species increased in abundance at low densities until peaking, after which B. albomaculata decreased when B. macloviana became more abundant, consistent with resource competition. We tested whether food may be a potential limiting resource by comparing the diet of both species. The two species consumed mostly polychaetes, differing only in the consumption of polychaetes from the family Nephthyidae, which was much higher for B. macloviana. Bathyraja macloviana could replace B. albomaculata at high densities when food resources may become scarce. These results support the hypothesis that competition release is an important factor explaining the changes in skate communities in overexploited areas.

  20. Intimal thickening of coronary arteries in the rabbitfish, Chimaera monstrosa L. (Chondrichthyes: Holocephali).

    Science.gov (United States)

    Durán, A C; Rodríguez, C; Gil de Sola, L; Fernández, B; Arqué, J M; Sans-Coma, V

    2010-08-01

    This study is the first to report the occurrence of intimal thickening of coronary arteries in a holocephalan, namely the rabbitfish, Chimaera monstrosa. The sample studied consisted of five hearts from rabbitfish with body weights ranging between 12 g and 1116 g. The specimens were fixed in formalin, in methanol:acetone:water (MAW), or in paraformaldehyde and were examined by brightfield and polarization light microscopy. Coronary arteries from three larger animals displayed focal intimal thickenings, which were located in the left main coronary artery trunk, at the level of the cono-ventricular junction, and in several intramyocardial ventricular arteries. The vascular changes were characterized by myointimal proliferation, breakage or absence of the inner elastic lamina, and, in one case, by increased collagen within the myointimal proliferation. Taking into account the severity of the coronary arterial changes, their location, and the body weight of the affected animals, we conclude that (1) these changes are age-related in the rabbitfish and (2) local intense mechanical tension seems to be an important factor in their formation in this species.

  1. Pectoral fin morphology of batoid fishes (Chondrichthyes: Batoidea): explaining phylogenetic variation with geometric morphometrics.

    Science.gov (United States)

    Franklin, Oliver; Palmer, Colin; Dyke, Gareth

    2014-10-01

    The diverse cartilaginous fish lineage, Batoidea (rays, skates, and allies), sister taxon to sharks, comprises a huge range of morphological diversity which to date remains unquantified and unexplained in terms of evolution or locomotor style. A recent molecular phylogeny has enabled us to confidently assess broadscale aspects of morphology across Batoidea. Geometric morphometrics quantifies the major aspects of shape variation, focusing on the enlarged pectoral fins which characterize batoids, to explore relationships between ancestry, locomotion and habitat. A database of 253 specimens, encompassing 60 of the 72 batoid genera, reveals that the majority of morphological variation across Batoidea is attributable to fin aspect-ratio and the chordwise location of fin apexes. Both aspect-ratio and apex location exhibit significant phylogenetic signal. Standardized independent linear contrast analysis reveals that fin aspect-ratio can predict locomotor style. This study provides the first evidence that low aspect-ratio fins are correlated with undulatory-style locomotion in batoids, whereas high aspect-ratio fins are correlated with oscillatory locomotion. We also show that it is phylogeny that determines locomotor style. In addition, body- and caudal fin-locomotors are shown to exhibit low aspect-ratio fins, whereas a pelagic lifestyle correlates with high aspect-ratio fins. These results emphasize the importance of phylogeny in determining batoid pectoral fin shape, however, interactions with other constraints, most notably locomotor style, are also highlighted as significant. © 2014 Wiley Periodicals, Inc.

  2. Functional morphology of undulatory pectoral fin locomotion in the stingray taeniura lymma (Chondrichthyes: dasyatidae)

    Science.gov (United States)

    Rosenberger; Westneat

    1999-12-01

    Rajiform locomotion is a unique swimming style found in the batoid fishes (skates and rays) in which thrust is generated by undulatory waves passing down the enlarged pectoral fins. We examined the kinematic patterns of fin motion and the motor patterns of pectoral fin muscles driving the locomotor system in the blue-spot stingray Taeniura lymma. Our goals in this study were to determine overall patterns of fin motion and motor control during undulatory locomotion, to discover how these patterns change with swimming velocity and to correlate muscle function with kinematics and pectoral morphology. Kinematic data were recorded from five individuals over a range of swimming speeds from 22 to 55 cm s(-)(1) (0.9-3.0 DL s(-)(1), where DL is body disc length). Electromyographic (EMG) data were recorded from three individuals over a range of velocities (1.2-3.0 DL s(-)(1)) at seven locations (four dorsal, three ventral) along the pectoral fin. As swimming velocity increases, fin-beat frequency, wavespeed and stride length increase, number of waves and reduced frequency decrease and fin amplitude remains constant. There is variability among individuals in frequency and amplitude at a given speed. An inverse relationship was found in which a high fin-beat frequency is associated with a low fin amplitude and a low fin-beat frequency is associated with a high fin amplitude. The motor pattern of undulatory locomotion is alternate firing activity in the dorsal and ventral muscles as the wave moves along the fin from anterior to posterior. Fin muscles are active along the entire length of the fin except at the lowest speeds. As swimming velocity and fin-beat frequency increase, the time of activation of posterior muscles becomes earlier relative to the onset of activity in the anterior dorsal muscles. The duration of muscle activity is longer in the ventral muscles than in the dorsal muscles, indicating that they play a central role in the power stroke of the fin-beat cycle. The anterior muscles (dorsal and ventral) are active for a relatively longer part of the stride cycle than the posterior muscles. Both the anterior position and the large duty factor of the anterior muscles reflect the role of these muscles in initial wave generation. Synchronous recordings of kinematic data with EMG data reveal that the anterior dorsal and middle ventral muscles do mostly positive work, whereas the dorsal and ventral posterior muscles do negative work at most swimming speeds.

  3. Karksilepis parva gen. et sp. nov. (Chondrichthyes from the Burtnieki Regional Stage, Middle Devonian of Estonia

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    Kleesment, Anne

    2008-12-01

    Full Text Available Dermal scales of a new chondrichthyan were discovered in four levels in sandstones of the Härma Beds (lower part of the Burtnieki Regional Stage, Middle Devonian in the Karksi outcrop of South Estonia. The classification of Karksilepis parva gen. et sp. nov. Märss is still uncertain.

  4. Reproductive biology of the southern thorny skate Amblyraja doellojuradoi (Chondrichthyes, Rajidae).

    Science.gov (United States)

    Delpiani, G

    2016-04-01

    The total lengths (L(T)) of 193 males (209-556 mm) and 130 females (275-515 mm) of Amblyraja doellojuradoi, a commercial by-catch species on the Argentinean continental shelf, which are increasingly retained, were analysed. No sexual dimorphism was observed in the L(T) at which 50% of individuals were sexually mature; males matured at 448 mm and females at 411 mm, c. 80 and 82% of maximum L(T). The hepato-somatic index was similar among sexes, but significantly different between maturity stages, being lower in mature than immature specimens. Males had no seasonal difference in the hepato-somatic index and females had the lowest index in autumn. The gonado-somatic index was lower in males than in females and significantly higher in mature than immature specimens of both sexes. Males had the highest index in autumn and females had no seasonal difference. Collectively, these results would indicate that A. doellojuradoi breeds in autumn.

  5. Historical and contemporary records of the angular rough shark Oxynotus centrina (Chondrichthyes; Oxynotidae in Turkish waters

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    H. KABASAKAL

    2010-10-01

    Full Text Available During the last 58 years, only 12 angular rough sharks were recorded in Turkish waters. Rare captures of the species in the area needs an immediate action for the conservation of O. centrina. To protect the habitat of O. centrina, strict regulations should be implemented for diving in the localities, where the angular rough sharks occur regularly. Protecting the habitat of the angular rough shark is an urgent need before subjecting O. centrina to 100% protection in the seas of Turkey.

  6. Inclusión de ensilado de pescado como alternativa en la elaboración de alimento extruido para el camarón de cultivo (Litopenaeus schmitti)

    OpenAIRE

    Balsinde, M.; Fraga, I.; Galindo, J.

    2003-01-01

    The artificial feeds elaboration for aquatic species, it has always used as conventional technology of pelletized prosecution. The artificial balanced feeds production for the commercial breeding of the shrimp constitutes the base of the feeding of most of the cultures of aquatic species in Cuba. In this work three diets were elaborated by the extrusion technology substituting flour of having fished by silage, according to the nutritional requirements recommended for the white shrimp (L...

  7. Distribuição diária das atividades comportamentais dos camarões marinhos Farfantepenaeus subtilis (Pérez Farfante, 1967) e Litopenaeus schmitti (Burkenroad, 1938) em condições laboratoriais

    OpenAIRE

    Medeiros, Melquieges Sousa de

    2008-01-01

    A aqüicultura marinha tem se destacado em todo o mundo, especialmente pelo cultivo de camarão. No Brasil, a introdução da espécie Litopenaeus vannamei contribuiu para o sucesso da atividade, embora existam algumas desvantagens associadas à introdução de uma espécie exótica, que estariam relacionadas ao aparecimento de novas enfermidades no ambiente, além do impacto ecológico sobre as espécies nativas. Uma necessidade apontada pelos diversos segmentos da carcinicultura é o incentivo à pesquisa...

  8. Primer registro de Harriota raleighiana (Chondrichthyes: Holocephali: Rhinochimaeridae en la costa del Pacífico central de México First record of Harriota raleighiana (Chondrichthyes: Holocephali: Rhinochimaeridae in the central Pacific coast of Mexico

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    José Luis Castro-Aguirre

    2007-12-01

    Full Text Available Este es el primer registro de la quimera narizona, Harriota raleighiana Goode y Bean 1895, en el litoral del Pacífico central de México, con base en una hembra moribunda, recolectada en la superficie del océano sobre agua muy profunda cerca de Manzanillo, Colima. También constituye el segundo registro de su existencia en el océano Pacífico oriental, lo que podría comprobar su patrón distribucional que la calificaría como cosmopolita. Se proporcionan sus medidas y algunos datos biológicos.This is the first record in Mexican central Pacific of the "longnosed chimaera" Harriota raleighiana Goode and Bean 1895, based on a nearly dead female specimen collected at sea surface over very deep water of Manzanillo, Colima. Also, it is the second published report on the occurrence of this species in the eastern Pacific ocean, and seems to support its geographical distribution pattern, which has been classified as cosmopolitan-like type. Morphometric and some biological data are also offered.

  9. New specimens and records of chondrichthyan fishes (Vertebrata: Chondrichthyes off the Mexican Pacific coast Nuevos ejemplares y nuevos registros de peces cartilaginosos (Vertebrata: Chondrichthyes de la costa del Pacífico mexicano

    Directory of Open Access Journals (Sweden)

    Gorgonio Ruiz-Campos

    2010-08-01

    Full Text Available New specimens and new records of occurrence for 10 species of chondrichthyan (elasmobranch and chimaeroid fishes previously unknown or little documented for the continental shelf of the Mexican Pacific are reported. This contribution provides the first record of Centroscyllium nigrum, Isurus paucus, and Bathyraja trachura for the Mexican Pacific, as well as new specimens of Hydrolagus colliei, Hexanchus griseus, Echinorhinus cookei, Pseudocarcharias kamoharai, and Raja velezi for the western coast of the Baja California Peninsula, including the intermediate record within the known distribution range for Apristurus kampae, and the southernmost record for Raja inornata.Se reportan nuevos ejemplares y nuevos registros de concurrencia para 10 especies de elasmobranquios previamente desconocidos o con muy poca documentación en aguas del Pacífico mexicano. Esta contribución ofrece el primer registro de Centroscyllium nigrum, Isurus paucus, y Bathyraja trachura en el Pacífico mexicano; así como nuevos ejemplares de Hydrolagus colliei, Hexanchus griseus, Echinorhinus cookei, Pseudocarcharias kamoharai y Raja velezi en la costa occidental de la península de Baja California, con la inclusión del registro intermedio en el ámbito de distribución conocida para Apristurus kampae, y el registro más meridional para Raja inornata.

  10. Anatomía del corazón y las arterias branquiales aferentes de las rayas (Chondrichthyes: Batoidea Anatomy of the heart and afferent branchial arteries of the rays (Chondrichthyes: Batoidea

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    Abraham Kobelkowsky

    2012-04-01

    Full Text Available Se selecionó el corazón y el sistema branquial aferente de Dasyatis sabina como patrón morfológico de los Batoidea. Se compararon las cámaras del corazón y la ramificación de la aorta ventral en las arterias branquiales aferentes con las correspondientes de especies representativas de otras familias de batoideos, tales como: Narcine brasiliensis (Narcinidae, Rhinobatos lentiginosus (Rhinobatidae, Raja texana (Rajidae, Urobatis jamaicensis (Urolophidae, Gymnura micrura (Gymnuridae y Myliobatis sp. (Myliobatidae. El análisis comparativo permitió reconocer como carácter más notable, la ausencia de las arterias innominadas posteriores en los Myliobatiformes, con excepción de Gymnuridae. Asimismo, permitió observar la amplia similitud entre Rhinobatidae y Rajidae, y entre Urotrygonidae y Dasyatidae.The heart and the afferent branchial system of the ray, Dasyatis sabina was selected as a morphologic pattern of the Batoidea. A comparison of the heart and the ramification of the ventral aorta into the branchial afferent arteries was made with the corresponding in representative species of other families of Batoidea, such as: Narcine brasiliensis (Narcinidae, Rhinobatos lentiginosus (Rhinobatidae, Raja texana (Rajidae, Urobatis jamaicensis (Urolophidae, Gymnura micrura (Gymnuridae, and Myliobatis sp. (Myliobatidae. The comparative analysis allows recognizing as the most notably character, the absence of the posterior innominates arteries in the Myliobatiformes, with the exception of Gymnuridae. A high similitude between Rhinobatidae and Rajidae, and Urolophidae and Dasyatidae was recognized.

  11. Claves taxonómicas para el reconocimiento dentario en taxa del superorden Rajomorphii de Chile (Chondrichthyes, Batoidea Taxonomic dental keys for the Chilean taxa of the superorder Rajomorphii (Chondrichthyes, Batoidea

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    Sylvia Sáez

    2012-07-01

    Full Text Available Se presenta claves taxonómicas basadas en características morfológicas dentarias externas e internas, que permiten el reconocimiento de cada orden, familia y género de los batoídeos conocidos en Chile. En algunos casos, como en las familias Rhinobatidae, Torpedinidae, Narcinidae, Myliobatidae, Mobulidae, Dasyatidae y Urotrygonidae, las claves permiten el reconocimiento específico pero, en otros casos, sólo se puede discriminar hasta género, dadas las limitaciones impuestas por los conocimientos existentes. Estas claves son una herramienta complementaria a la diagnosis de rayas y están orientadas al reconocimiento de fragmentos dentales, hallazgos paleontológicos de dientes así como para las piezas dentales asociadas con la mandíbula. De esta manera, se entrega un apoyo taxonómico nuevo con características dentales diferentes a las consideradas actualmente para este superorden.A series of keys with external and internal dental morphologic features for the identification of each order, family and genus of rays and skates of the batoids known in Chile, are presented. In the case of families Rhinobatidae, Torpedinidae, Narcinidae, Myliobatidae, Mobulidae, Dasyatidae and Urotrygonidae, an identification at the species level is possible. In other cases, due to limitations imposed by the existing knowledge, only discrimination up to genus is allowed. These keys are a complementary tool for the diagnosis of rays suitable for the identification of dental fragments, paleontological discoveries of teeth as well as for jaw teeth. This tool offers a novel taxonomic support, which includes dental features different from those considered nowadays for this superorder.

  12. A new species of Neotropical freshwater stingray (Chondrichthyes: Potamotrygonidae) from the Rio Negro, Amazonas, Brazil: the smallest species of Potamotrygon.

    Science.gov (United States)

    Carvalho, Marcelo R De; Rosa, Ricardo S; Araújo, Maria Lúcia G De

    2016-05-04

    A new species of Potamotrygon is described from the Rio Negro drainage, Amazonas, Brazil. In spite of being cited or pictured several times in the scientific and aquarium fish literature since the 19th Century, it had been misidentified and still lacked a scientific name. Potamotrygon wallacei, n. sp., is diagnosed by the following characters: dorsal surface of disc light brown, with black irregularly-shaped vermiculate markings forming an amphora- or Ω-shaped figure on mid-disc, delimiting light brown reniform areas at disc center, and with subcircular light brown ocellate markings on disc margins; small body size (smallest known Potamotrygon species; largest examined specimen measured 310 mm DW); dorsal spines on tail usually rather low, without broad bases, in one to rarely three irregular rows, but extending posteriorly only to tail mid-length and not to caudal stings, with altogether relatively few spines; denticles on posterior mid-disc and tail base Y-shaped, with a central, anterior, bulbous cusp and usually two posterior pairs of smaller, rounded cusps; and single (anterior) angular cartilage. The new species is similar to P. orbignyi and other "reticulated" species in having a single (anterior) angular cartilage and in the color pattern of the tail, but is easily distinguished based on its size, dorsal tail spine arrangement, and specific details of color pattern.

  13. Evidence of stability in a chondrichthyan population: case study of the spotted ratfish Hydrolagus colliei (Chondrichthyes: Chimaeridae).

    Science.gov (United States)

    Barnett, L A K; Ebert, D A; Cailliet, G M

    2012-04-01

    Results presented here provide evidence of an exception to the generalization that all chondrichthyan populations are especially vulnerable to exploitation to the extent that they remain at low abundance for a protracted or indefinite duration even after exploitation rates are reduced. Delta log-normal generalized linear models (GLM) and cluster analysis of fishery-independent catch-per-unit-effort (CPUE) data from 1977 to 2006 indicated the presence of at least two distinct stocks of spotted ratfish Hydrolagus colliei off the U.S. West Coast. CPUE of the continental slope and northern continental shelf and upper slope populations did not vary between 1977 and 1995 and increased from 1995 to 2006. On the basis of the timing of these changes, it is likely that both fishing and climate influenced these trends. Sex and size-specific differences in bathymetric distribution, along with the identification of nursery sites, indicate that fishery by-catch could have a significant effect on population growth. These aggregative behaviours, combined with low fecundity, indicate that H. colliei may be vulnerable to irreversible population depletion by fisheries mortality. Temporal abundance trends indicated, however, that their population size has increased significantly within the last decade, a demonstration of population stability. A literature review indicated that there is also evidence for population stability in other chondrichthyans. The paradigm that all chondrichthyan populations fail to rebuild in response to exploitation, therefore, may not be as broadly applicable as previously thought. Thus, it is not necessarily sufficient to make generalizations regarding the vulnerability of chondrichthyans across higher taxonomic scales. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  14. A new paleozoic Symmoriiformes (Chondrichthyes from the late Carboniferous of Kansas (USA and cladistic analysis of early chondrichthyans.

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    Alan Pradel

    Full Text Available BACKGROUND: The relationships of cartilaginous fishes are discussed in the light of well preserved three-dimensional Paleozoic specimens. There is no consensus to date on the interrelationship of Paleozoic chondrichthyans, although three main phylogenetic hypotheses exist in the current literature: 1. the Paleozoic shark-like chondrichthyans, such as the Symmoriiformes, are grouped along with the modern sharks (neoselachians into a clade which is sister group of holocephalans; 2. the Symmoriiformes are related to holocephalans, whereas the other Paleozoic shark-like chondrichthyans are related to neoselachians; 3. many Paleozoic shark-like chondrichthyans, such as the Symmoriiformes, are stem chondrichthyans, whereas stem and crown holocephalans are sister group to the stem and crown neoselachians in a crown-chondrichthyan clade. This third hypothesis was proposed recently, based mainly on dental characters. METHODOLOGY/PRINCIPAL FINDINGS: On the basis of two well preserved chondrichthyan neurocrania from the Late Carboniferous of Kansas, USA, we describe here a new species of Symmoriiformes, Kawichthys moodiei gen. et sp. nov., which was investigated by means of computerized X-ray synchrotron microtomography. We present a new phylogenetic analysis based on neurocranial characters, which supports the third hypothesis and corroborates the hypothesis that crown-group chondrichthyans (Holocephali+Neoselachii form a tightly-knit group within the chondrichthyan total group, by providing additional, non dental characters. CONCLUSIONS/SIGNIFICANCE: Our results highlight the importance of new well preserved Paleozoic fossils and new techniques of observation, and suggest that a new look at the synapomorphies of the crown-group chondrichthyans would be worthwhile in terms of understanding the adaptive significance of phylogenetically important characters.

  15. Evolution of Two Short Interspersed Elements in Callorhinchus milii (Chondrichthyes, Holocephali) and Related Elements in Sharks and the Coelacanth

    Science.gov (United States)

    Plazzi, Federico; Mantovani, Barbara

    2017-01-01

    Abstract Short interspersed elements (SINEs) are non-autonomous retrotransposons. Although they usually show fast evolutionary rates, in some instances highly conserved domains (HCDs) have been observed in elements with otherwise divergent sequences and from distantly related species. Here, we document the life history of two HCD-SINE families in the elephant shark Callorhinchus milii, one specific to the holocephalan lineage (CmiSINEs) and another one (SacSINE1-CM) with homologous elements in sharks and the coelacanth (SacSINE1s, LmeSINE1s). The analyses of their relationships indicated that these elements share the same 3′-tail, which would have allowed both elements to rise to high copy number by exploiting the C. milii L2-2_CM long interspersed element (LINE) enzymes. Molecular clock analysis on SINE activity in C. milii genome evidenced two replication bursts occurring right after two major events in the holocephalan evolution: the end-Permian mass extinction and the radiation of modern Holocephali. Accordingly, the same analysis on the coelacanth homologous elements, LmeSINE1, identified a replication wave close to the split age of the two extant Latimeria species. The genomic distribution of the studied SINEs pointed out contrasting results: some elements were preferentially sorted out from gene regions, but accumulated in flanking regions, while others appear more conserved within genes. Moreover, data from the C. milii transcriptome suggest that these SINEs could be involved in miRNA biogenesis and may be targets for miRNA-based regulation. PMID:28505260

  16. Morphological study of the oviductal gland in the smallnose fanskate Sympterygia bonapartii (Müller and Henle, 1841 (Chondrichthyes, Rajidae

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    EJ Galíndez

    Full Text Available The oviductal gland is an exclusive structure of cartilaginous fishes that produces the egg jelly, forms the tertiary egg envelopes and stores sperm. The biological importance of this structure is related to the special features of the reproductive strategy of the group and to its phylogeny, considering that egg-laying is the ancestral condition in this fish (Dulvy and Reynolds, 1997. This gland of the smallnose fanskate shows four morphofunctional zones. The lining epithelium along the gland is columnar with secretory and ciliated cells. Secretions are mucous and/or proteic according to the zone, and to their specific functions. This is the first report about the microanatomy of the female reproductive tract of S. bonapartii with evidence of sperm storage in the genus.

  17. Taxonomic research on Squalus megalops (Macleay, 1881 and Squalus blainvillei (Risso, 1827 (Chondrichthyes: Squalidae in Tunisian waters (central Mediterranean Sea

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    Sondes Marouani

    2011-11-01

    Full Text Available Two species of spurdog of the genus Squalus occur in the Gulf of Gabès (southern Tunisia, central Mediterranean: the longnose spurdog Squalus blainvillei (Risso, 1827 and a short-snout spurdog of the Squalus megalops-cubensis group. Morphometric and meristic data as well as a genetic analyses (DNA inter-simple sequence repeat markers and molecular barcoding methods support the assignation of this short-snout spurdog to Squalus megalops (Macleay, 1881. Squalus megalops occurs commonly in temperate and tropical Australian waters, and is also thought to occur in the eastern Atlantic, southern Indian Ocean and western North Pacific although these records need to be confirmed. Our study confirms that it occurs in the Mediterranean Sea. Populations of both S. blainvillei and S. megalops are described based on Tunisian material.

  18. Systemic rhabdomyolysis induced by venom of freshwater stingrays Plesiotrygon iwamae and Potamotrygon motoro (Chondrichthyes-Potamotrygonidae) from the Amazon Basin.

    Science.gov (United States)

    Lameiras, Juliana Luiza Varjão; da Costa, Oscar Tadeu Ferreira; Moroni, Fábio Tonissi; Araújo, José de Ribamar; Caranhas, Sandra Maria Evangelista; Marques, Carlos Melquiades Almeida; Dos-Santos, Maria Cristina; Duncan, Wallice Luiz Paxiúba

    2014-01-01

    Injuries caused by freshwater stingrays are characterized by intense pain and pathological changes at the lesion site, including oedema, erythema and, in most cases, necrosis. In this study, the systemic myotoxic activity induced by mucus extracts from the dorsal region and stinger of the stingrays Plesiotrygon iwamae and Potamotrygon motoro was described, analysed and quantified. Twenty-four hours after injection of 400 μg of the extracts into the gastrocnemius muscle of mice, the following effects were observed: coagulative necrosis of the muscle tissue, muscle fibre regeneration and the presence of inflammatory infiltrates, including neutrophils, macrophages, and a reduced number of eosinophils and lymphocytes. These changes were also observed, although to a lesser extent, in the gastrocnemius muscles of the contralateral limbs, demonstrating that the extracts from the two species could induce systemic rhabdomyolysis. Based on morphometric analysis, it was observed that the stinger extract of P. motoro was more potent in inducing local and systemic myotoxic activity, followed by the dorsal extract from P. motoro and stinger and dorsal extracts from P. iwamae, which induced similar effects.

  19. 软骨鱼类染色体研究进展%Progress of studies on chromosome of Chondrichthyes

    Institute of Scientific and Technical Information of China (English)

    谢仰杰; 翁朝红; 苏永全; 王军

    2006-01-01

    在各类脊椎动物中,软骨鱼类是开展染色体研究最少的类群.迄今为止,文献共报道了70种软骨鱼的核型,仅占现生838种软骨鱼类的8.35%,包括31种鲨类,37种鳐类和2种全头类.已报道的软骨鱼类二倍体染色体数为52~104(巴西双鳍电鳐二倍体染色体数为28例外),常存在微染色体.在不同的分类阶元,相对原始的软骨鱼类具有较多的染色体数,端部和亚端部着丝粒染色体较多,多有微染色体.软骨鱼类染色体进化趋势表现为个体染色体数目的减少,中部和亚中部着丝粒染色体数目的增多,并伴随微染色体的消失.软骨鱼类是核DNA含量较大的脊椎动物.已报道144种软骨鱼类的核DNA含量,其变化较大,为3.0~34.1pg/N,全头类的核DNA含量最小,角鲨目和扁鲨目的核DNA含量最大.近年来,在软骨鱼类染色体的C带、核仁组织区(NOR)染色、限制性内切酶显带、特异DNA探针如端粒序列和短散布重复序列(SINE序列)的荧光原位杂交等方面取得了较大进展.现代分子生物学技术也被用于一些软骨鱼类的基因组研究,在重复DNA序列、随体DNA家族和微卫星位点等方面均取得一些成果.

  20. Strongly directional and differential swimming behavior of an adult female white shark, Carcharodon carcharias (Chondrichthyes: Lamnidae from Guadalupe Island, Mexico

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    Ramón Bonfil

    2015-03-01

    Full Text Available We report on an adult female white shark tracked for 288 days and 7,100 km in the NE Pacific Ocean. The shark, tagged with a real-time satellite tag off Guadalupe Island, Mexico in October 2006, remained around the island for 3.5 months but left in early February 2007 for a ca. 3,900 km westward migration. Heading and swimming speed data showed that: a the arc-like route followed by this shark during oceanic travel involved strongly directional rapid movement, and b once the shark arrived to a specific (ca. 680 km wide area located 790 km north-northeast of the Hawaiian Islands, it switched into a distinct roaming behavior. The shark remained in this roaming area from late March to at least late July 2007. We show that real-time satellite tags can provide unique and valuable information about the migratory behavior of white sharks.

  1. Phylogeography and conservation genetics of the Amazonian freshwater stingray Paratrygon aiereba Müller & Henle, 1841 (Chondrichthyes: Potamotrygonidae

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    Renata G. Frederico

    Full Text Available The family Potamotrygonidae is monophyletic comprising three genera: Paratrygon Duméril, Potamotrygon Garman and Plesiotrygon Rosa, Castello & Thorson. The distribution of most species in this family is restricted to a single basin or fluvial system. Only Potamotrygon motoro, Potamotrygon orbignyi and Paratrygon aiereba are found in more than one river basin. In this study we investigate genetic structuring of Paratrygon aiereba, from five rivers of the Amazon region: Negro, Solimões-Amazon-Estuary system, Tapajós, Xingu and Araguaia. Sixty-three individuals were sequenced for ATPase 6, and a representative subsample of 27 individuals was sequenced for COI. The COI dataset analysis indicated that Paratrygon is sister to all other potamotrygonid genera and species. Population parameters inferred from the analysis of ATPase 6 sequences revealed that the populations of this species are structured within each river, with no or nearly non-existent gene flow occurring between rivers and a positive correlation between geographic and genetic distances. Paratrygon aiereba is comprised of three geographically restricted clades with K2P interclade distances of at least 2%. Intraspecific divergence within P. aiereba is similar to the interspecific divergence observed in Potamotrygon spp. sampled throughout the same geographic area. Using the premises of COI barcoding and the allopatric distribution of the three P. aiereba clades, the taxon P. aiereba most likely comprises three distinct biological species. Since freshwater stingrays of the family Potamotrygonidae are highly exploited for the aquarium trade, management and conservation strategies need to be implemented at the level of each river basin, rather than at the level of the Amazon basin.

  2. Insectivory in Potamotrygon signata (Chondrichthyes: Potamotrygonidae, an endemic freshwater stingray from the Parnaíba River basin, northeastern Brazil

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    G. Moro

    Full Text Available Potamotrygon signata is an endemic freshwater stingray species in the Parnaíba River basin, Brazil. After its original description, only citations in systematic lists were recorded in the literature and the biology of the species remains unknown, including the feeding habits. The aim of this study is to characterize the overall diet of P. signata based on analysing stomach contents and to provide preliminary information on intraspecific diet variability between sexes and maturity stages. The stomach contents of 56 specimens of P. signata were analyzed. The taxonomic identification of food items showed the presence of 13 prey orders, including insects, mollusks, crustaceans and teleost fish. The Index of Relative Importance (IRI% indicated P. signata as an insectivorous species, with a dominance of Diptera larvae (60.64% and Ephemeroptera nymphs (34.68%. Differences in diet were observed between sexes, as well as between mature and immature individuals. The IRI% of females showed a similar occurrence of Diptera and Ephemeroptera (47.12% and 47.86%, respectively, whereas for males, Ephemeroptera was the main item (79.56%. Immature individuals showed a dominance of Diptera (76.20% while mature individuals showed a similar occurrence of Diptera (46.95% and Ephemeroptera (47.23%. The observed sexual and ontogenetic differences in diet may be related to distinct nutritional requirements of males and females, and to the variation of morphological aspects of the oral apparatus and dentition of males and females and of immature individuals and adults. The essentially insectivorous diet of the species is possibly adaptively advantageous in the Caatinga semi-arid environment, where the availability of fish as prey may be subject to strong seasonal variation.

  3. Next generation sequencing yields complete mitogenomes of Leopard whipray (Himantura leoparda) and Blue-spotted stingray (Neotrygon kuhlii) (Chondrichthyes: Dasyatidae).

    Science.gov (United States)

    Shen, Kang-Ning; Chang, Chih-Wei; Tsai, Shiou-Yi; Wu, Shan-Chun; Lin, Zi-Han; Chan, Yen-Fan; Chen, Ching-Hung; Hsiao, Chung-Der; Borsa, Philippe

    2016-07-01

    The Leopard whipray (Himantura leoparda) and Blue-spotted stingray (Neotrygon kuhlii) are distributed in the Indian and West Pacific Ocean and considered as complex species based on morphological and molecular evidences. In this study, we used the next-generation sequencing method to decode two complete mitogenomes of H. leoparda and N. kuhlii. The assembled mitogenome, consisting lengths of 17,690 bp for H. leoparda and 17,974 bp for N. kuhlii, shows 78% identity to each other. Both mitogenomes follow the typical vertebrate arrangement, including 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNAs genes and a non-coding control region of D-loop. D-loop with the lengths 1931 bp (H. leoparda) and 2243 bp (N. kuhlii) is located between tRNA-Pro and tRNA-Phe. The overall GC content is 40.3% for H. leoparda and 39.8% for N. kuhlii. The complete mitogenome of H. leoparda and N. kuhlii provides essential and important DNA molecular data for further phylogenetic and evolutionary analyses for stingray species complex.

  4. Insectivory in Potamotrygon signata (Chondrichthyes: Potamotrygonidae), an endemic freshwater stingray from the Parnaíba River basin, northeastern Brazil.

    Science.gov (United States)

    Moro, G; Charvet, P; Rosa, R S

    2012-11-01

    Potamotrygon signata is an endemic freshwater stingray species in the Parnaíba River basin, Brazil. After its original description, only citations in systematic lists were recorded in the literature and the biology of the species remains unknown, including the feeding habits. The aim of this study is to characterize the overall diet of P. signata based on analysing stomach contents and to provide preliminary information on intraspecific diet variability between sexes and maturity stages. The stomach contents of 56 specimens of P. signata were analyzed. The taxonomic identification of food items showed the presence of 13 prey orders, including insects, mollusks, crustaceans and teleost fish. The Index of Relative Importance (IRI%) indicated P. signata as an insectivorous species, with a dominance of Diptera larvae (60.64%) and Ephemeroptera nymphs (34.68%). Differences in diet were observed between sexes, as well as between mature and immature individuals. The IRI% of females showed a similar occurrence of Diptera and Ephemeroptera (47.12% and 47.86%, respectively), whereas for males, Ephemeroptera was the main item (79.56%). Immature individuals showed a dominance of Diptera (76.20%) while mature individuals showed a similar occurrence of Diptera (46.95%) and Ephemeroptera (47.23%). The observed sexual and ontogenetic differences in diet may be related to distinct nutritional requirements of males and females, and to the variation of morphological aspects of the oral apparatus and dentition of males and females and of immature individuals and adults. The essentially insectivorous diet of the species is possibly adaptively advantageous in the Caatinga semi-arid environment, where the availability of fish as prey may be subject to strong seasonal variation.

  5. Ecology of endoparasites of the fluvial stingray Potamotrygon falkneri (Chondrichthyes: Potamotrygonidae from the upper Paraná River floodplain, Brazil

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    ACF. Lacerda

    Full Text Available The present study investigated the ecological relationships between endoparasites and the host Potamotrygon falkneri from the upper Paraná River by using as indicators the host's relative condition factor (Kn, sex and hepatosomatic relation (HSR. Forty-seven specimens of P. falkneri were analyzed between March 2005 and September 2006. Statistical analysis showed that the Kn was positively correlated with the abundance of Acanthobothrium regoi and Rhinebothrium paratrygoni; only the abundance of A. regoi was positively correlated to the HSR, whereas R. paratrygoni did not present correlation and there was no influence of the host's sex on the abundance and prevalence of parasites. This is the first study concerning the ecology of parasites of potamotrygonids.

  6. Potamotrygon limai, sp. nov., a new species of freshwater stingray from the upper Madeira River system, Amazon basin (Chondrichthyes: Potamotrygonidae).

    Science.gov (United States)

    Fontenelle, João Pedro; Da Silva, João Paulo C B; De Carvalho, Marcelo R

    2014-02-18

    Potamotrygon limai, sp. nov., is described from the Jamari River, upper Madeira River system (Amazon basin), state of Rondônia, Brazil. This new species differs from congeners by presenting unique polygonal or concentric patterns formed by small whitish spots better defined over the posterior disc and tail-base regions. Potamotrygon limai, sp. nov., can be further distinguished from congeners in the same basin by other characters in combination, such as two to three rows of midtail spines converging to a single irregular row at level of caudal sting origin, proportions of head, tail and disc, patterns of dermal denticles on rostral, cranial and tail regions, among other features discussed herein. Potamotrygon limai, sp. nov., is most similar to, and occurs sympatrically with, P. scobina, and is distinguished from it by lacking ocellated spots on disc, by its characteristic polygonal pattern on posterior disc, a comparatively much shorter and broader tail, greater intensity of denticles on disc, more midtail spine rows at tail-base, and other features including size at maturity and meristic characters. Potamotrygon limai, sp. nov., is also distinguished from other species of Potamotrygon occurring in the Amazon region, except P. scobina, by presenting three angular cartilages (vs. two or one). This new species was discovered during a detailed taxonomic and morphological revision of the closely related species P. scobina, and highlights the necessity for thorough and all-embracing taxonomic studies, particularly in groups with pronounced endemism and morphological variability.

  7. New tropical carcharhinids (chondrichthyes, carcharhiniformes) from the late Eocene early Oligocene of Balochistan, Pakistan: Paleoenvironmental and paleogeographic implications

    Science.gov (United States)

    Adnet, S.; Antoine, P.-O.; Hassan Baqri, S. R.; Crochet, J.-Y.; Marivaux, L.; Welcomme, J.-L.; Métais, G.

    2007-04-01

    New selachians (sharks and rays) have been collected from several late Eocene and early Oligocene marine localities in the Bugti Hills (Balochistan, Pakistan). Two new species of Requiem sharks (close to the Recent "Bull shark") are described : Carcharhinus balochensis and Carcharhinus perseus. The rest of the fauna is notable for the strong representation of Carcharhiniformes. These selachian faunas represent a unique tropical association for the Oligocene period and one of the first modern tropical selachian faunas, with modern taxa such as the two new species of "Bull sharks", Negaprion sp. and one of the first occurrences of Sphyrna sp. Moreover, these faunas permit paleoenvironmental interpretation of adjacent land masses. The relatively modern aspect of these faunas, compared with other contemporaneous and younger selachian associations from Atlantic and Mediterranean seas, suggests biogeographic isolation of selachian communities living in eastern and western parts of the Tethys before its final closure during the early-middle Miocene.

  8. Functional analysis of the musculo-skeletal system of the gill apparatus in Heptranchias perlo (Chondrichthyes: Hexanchidae).

    Science.gov (United States)

    Kryukova, Nadezhda V

    2017-08-01

    Musculo-skeletal morphology is an indispensable source for understanding functional adaptations. Analysis of morphology of the branchial apparatus of Hexanchiform sharks can provide insight into aspects of their respiration that are difficult to observe directly. In this study, I compare the structure of the musculo-skeletal system of the gill apparatus of Heptranchias perlo and Squalus acanthias in respect to their adaptation for one of two respiratory mechanisms known in sharks, namely, the active two-pump (oropharyngeal and parabranchial) ventilation and the ram-jet ventilation. In both species, the oropharyngeal pump possesses two sets of muscles, one for compression and the other for expansion. The parabranchial pump only has constrictors. Expansion of this pump occurs only due to passive elastic recoil of the extrabranchial cartilages. In Squalus acanthias the parabranchial chambers are large and equipped by powerful superficial constrictors. These muscles and the outer walls of the parabranchial chambers are much reduced in Heptranchias perlo, and thus it likely cannot use this pump. However, this reduction allows for vertical elongation of outer gill slits which, along with greater number of gill pouches, likely decreases branchial resistance and, at the same time, increases the gill surface area, and can be regarded as an adaptation for ram ventilation at lower speeds. © 2017 Wiley Periodicals, Inc.

  9. Paratrygon aiereba (Müller & Henle, 1841: the senior synonym of the freshwater stingray disceus thayeri Garman, 1913 (chondrichthyes: potamotrygonidae

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    Ricardo S. Rosa

    1990-01-01

    Full Text Available A review of the original descriptions and available types of the South American freshwater stingrays Trygon aiereba Müller & Henle, 1841, Trygon strogylopterus Schomburgk, 1843 and Disceus thayeri Garman, 1913 indicates that these three nominal species are synonymous. The senior name, placed in the monotypic genus Paratrygon Duméril, 1865, established for Trygon aiereba, is available and valid. Based on its description, T. aiereba is a freshwater stingray. Therefore, this taxon is not the same as Raja ajereba Walbaum and Raja orbicularis Schneider, both names established for the marine "Aiereba" of Marcgrave, and which preferably should be treated as nomina dubia. Paratrygon does not replace Potamotrygon Garman, 1877 as the type genus, because the family name Potamotrygonidae Garman, 1877 has priority over Paratrygonidade Gill, 1893.A revisão das descrições originais e dos tipos existentes das raias de água doce Trygon aiereba Müller & Henle, 1841, Trygon strogylopterus Schomburgk, 1843, e Disceus thayeri Garman, 1913, indica que essas três espécies nominais são sinônimas. O nome sênior, colocado no gênero monotípico Paratrygon Duméril, 1865, estabelecido para T. aiereba, é disponível e válido. A descrição de T. aiereba corresponde claramente a uma raia de agua doce; portanto esta espécie não é um sinônimo de Raja ajereba Walbaum e de Raja orbicularis Schneider, ambos os nomes propostos para a "Aiereba " marinha de Marcgrave, e que preferivelmente devem ser tratados como nomina dubia. Paratrygon não substitui Potamotrygon Garman, 1877 como gênero-tipo, porque o nome de família Potamotrygonidae Garman, 1877 tem prioridade sobre Paratrygonidae Gill. 1893.

  10. A new Xenacanthiformes shark (Chondrichthyes, Elasmobranchii from the Late Paleozoic Rio do Rasto Formation (Paraná Basin, Southern Brazil

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    VICTOR E. PAULIV

    2014-03-01

    Full Text Available The Brazilian records on Xenacanthiformes include teeth and cephalic spines from the Parnaíba, Amazonas and Paraná basins. This work describes a new species of Xenacanthidae, collected in an outcrop of Serrinha Member of Rio do Rasto Formation (Wordian to Wuchiapingian, Paraná Basin, municipality of Jacarezinho, State of Paraná. The teeth of the new species are two or three-cuspidated and the aboral surface show a smooth concavity and one rounded basal tubercle. The coronal surface presents one semi-spherical and subcircular coronal button, and also two lateral main cusps and one central (when present with less than one fifth of the size of the lateral cusps in the labial portion. The lateral cusps are asymmetric or symmetric, rounded in transversal section, lanceolate in longitudinal section, devoid of lateral carinae and lateral serrations, and with few smooth cristae of enameloid. In optical microscope the teeth show a trabecular dentine (osteodentine base, while the cusps are composed by orthodentine, and the pulp cavities are non-obliterated by trabecular dentine. The fossil assemblage in the same stratigraphical level and in the whole Rio do Rasto Formation indicates another freshwater record for xenacanthid sharks.

  11. Neuropeptide Y immunohistochemistry and ultrastructure of developing chromaffin tissue in the cloudy dogfish, Scyliorhinus torazame (Chondrichthyes, Elasmobranchii).

    Science.gov (United States)

    Chiba, A

    2001-02-01

    Ontogenetic changes in neuropeptide Y-like immunoreactivity (NPY-LI) were studied in chromaffin tissue of the cloudy dogfish, Scyliorhinus torazame. In adults and post-hatching juveniles, NPY-LI was demonstrated in chromaffin cells, but not in ganglion cells and supporting cells. Immunoreactive fibers were also found in the axillary body (the major chromaffin tissue) of the adult fish. During the embryonic period, NPY-LI was found at first in chromaffin tissue in the 34-mm stage. In this stage, cells in the periphery of the tissue were positive for NPY. Afterwards, changes were not observed in the topography and relative dominance of labelled cells in the tissue. Transmission electron microscopy of chromaffin tissue of the 26-mm stage showed an early phase of histogenesis in rudimental cell clusters composed of agranular cells and a few granular cells, i.e. pheochromoblasts. In the 43-mm stage, differentiation of the chromaffin tissue enabled ultrastructural classification of adrenalin-producing cells, noradrenalin-producing cells, ganglion cells, supporting cells, and unmyelinated nerve fibers. These results suggest that in the dogfish the appearance of NPY-LI in the developing sympathoadrenal system is related to differentiation of chromaffin cells.

  12. Cloning and functional characterization of Chondrichthyes, cloudy catshark, Scyliorhinus torazame and whale shark, Rhincodon typus estrogen receptors.

    Science.gov (United States)

    Katsu, Yoshinao; Kohno, Satomi; Narita, Haruka; Urushitani, Hiroshi; Yamane, Koudai; Hara, Akihiko; Clauss, Tonya M; Walsh, Michael T; Miyagawa, Shinichi; Guillette, Louis J; Iguchi, Taisen

    2010-09-15

    Sex-steroid hormones are essential for normal reproductive activity in both sexes in all vertebrates. Estrogens are required for ovarian differentiation during a critical developmental stage and promote the growth and differentiation of the female reproductive system following puberty. Recent studies have shown that environmental estrogens influence the developing reproductive system as well as gametogenesis, especially in males. To understand the molecular mechanisms of estrogen actions and to evaluate estrogen receptor-ligand interactions in Elasmobranchii, we cloned a single estrogen receptor (ESR) from two shark species, the cloudy catshark (Scyliorhinus torazame) and whale shark (Rhincodon typus) and used an ERE-luciferase reporter assay system to characterize the interaction of these receptors with steroidal and other environmental estrogens. In the transient transfection ERE-luciferase reporter assay system, both shark ESR proteins displayed estrogen-dependent activation of transcription, and shark ESRs were more sensitive to 17beta-estradiol compared with other natural and synthetic estrogens. Further, the environmental chemicals, bisphenol A, nonylphenol, octylphenol and DDT could activate both shark ESRs. The assay system provides a tool for future studies examining the receptor-ligand interactions and estrogen disrupting mechanisms in Elasmobranchii.

  13. A new Xenacanthiformes shark (Chondrichthyes, Elasmobranchii) from the Late Paleozoic Rio do Rasto Formation (Paraná Basin), Southern Brazil.

    Science.gov (United States)

    Pauliv, Victor E; Dias, Eliseu V; Sedor, Fernando A; Ribeiro, Ana Maria

    2014-03-01

    The Brazilian records on Xenacanthiformes include teeth and cephalic spines from the Parnaíba, Amazonas and Paraná basins. This work describes a new species of Xenacanthidae, collected in an outcrop of Serrinha Member of Rio do Rasto Formation (Wordian to Wuchiapingian), Paraná Basin, municipality of Jacarezinho, State of Paraná. The teeth of the new species are two or three-cuspidated and the aboral surface show a smooth concavity and one rounded basal tubercle. The coronal surface presents one semi-spherical and subcircular coronal button, and also two lateral main cusps and one central (when present) with less than one fifth of the size of the lateral cusps in the labial portion. The lateral cusps are asymmetric or symmetric, rounded in transversal section, lanceolate in longitudinal section, devoid of lateral carinae and lateral serrations, and with few smooth cristae of enameloid. In optical microscope the teeth show a trabecular dentine (osteodentine) base, while the cusps are composed by orthodentine, and the pulp cavities are non-obliterated by trabecular dentine. The fossil assemblage in the same stratigraphical level and in the whole Rio do Rasto Formation indicates another freshwater record for xenacanthid sharks.

  14. Stomach contents and notes on the reproduction of the Onefin Skate Gurgesiella dorsalifera (Chondrichthyes: Rajidae off Southern Brazil

    Directory of Open Access Journals (Sweden)

    Getulio Rincon

    Full Text Available The Brazilian endemic deep-water onefin skate (Gurgesiella dorsalifera is a rare small species recently described in the 80's. No biological information is available on this species and its extremely restricted geographic distribution has been used to classify it as a vulnerable species under IUCN red list criteria. Twenty four specimens (115 to 207 mm disc width were captured off southern Brazilian coast at the region of Cape Santa Marta Grande (State of Santa Catarina by deep-water otter trawl (430-524 m. The analysis of stomach contents revealed an apparent opportunistic predation on juveniles of Urophycis brasiliensis (IRI = 6944, with an average total length of 21 mm, followed by mysidaceans (IRI = 2938, unidentified teleosts (IRI = 1969, the copepod Bradyidius plinioi (IRI = 393, and decapod crustaceans (IRI = 297. One mature female with 207 mm DW had two egg cases in its uteri.

  15. Morphological study of the oviductal gland in the smallnose fanskate Sympterygia bonapartii (Müller and Henle, 1841) (Chondrichthyes, Rajidae).

    Science.gov (United States)

    Galíndez, E J; Díaz-Andrade, M C; Avaca, M S; Estecondo, S

    2010-05-01

    The oviductal gland is an exclusive structure of cartilaginous fishes that produces the egg jelly, forms the tertiary egg envelopes and stores sperm. The biological importance of this structure is related to the special features of the reproductive strategy of the group and to its phylogeny, considering that egg-laying is the ancestral condition in this fish (Dulvy and Reynolds, 1997). This gland of the smallnose fanskate shows four morphofunctional zones. The lining epithelium along the gland is columnar with secretory and ciliated cells. Secretions are mucous and/or proteic according to the zone, and to their specific functions. This is the first report about the microanatomy of the female reproductive tract of S. bonapartii with evidence of sperm storage in the genus.

  16. DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in 'ray' products sold across Ireland and the UK.

    Science.gov (United States)

    Griffiths, Andrew Mark; Miller, Dana D; Egan, Aaron; Fox, Jennifer; Greenfield, Adam; Mariani, Stefano

    2013-01-01

    Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba). Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of "skate" or "ray". The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., "winged") and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene) was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura), spotted ray (Raja montagui), thornback ray (Raja clavata), cuckoo ray (Leucoraja naevus) small-eyed ray (Raja microocellata) and shagreen ray (Leucoraja fullonica). Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a single retailer chain labelled their wings as originating from three smaller-growing species (generally to be considered of lower conservation concern); of the six samples analysed from this company a third were mislabelled and originated from the thornback ray (a larger species that is currently undergoing population declines).

  17. DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in ‘ray’ products sold across Ireland and the UK

    Science.gov (United States)

    Egan, Aaron; Fox, Jennifer; Greenfield, Adam; Mariani, Stefano

    2013-01-01

    Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba). Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of “skate” or “ray”. The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., “winged”) and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene) was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura), spotted ray (Raja montagui), thornback ray (Raja clavata), cuckoo ray (Leucoraja naevus) small-eyed ray (Raja microocellata) and shagreen ray (Leucoraja fullonica). Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a single retailer chain labelled their wings as originating from three smaller-growing species (generally to be considered of lower conservation concern); of the six samples analysed from this company a third were mislabelled and originated from the thornback ray (a larger species that is currently undergoing population declines). PMID:24024082

  18. Microanatomy of the ovary of Atlantoraja platana (Günther, 1880) (Chondrichthyes, Rajidae)

    OpenAIRE

    Moya, Ana Carolina; Galíndez, Elena Juana; Di Giacomo, Edgardo Ernesto

    2013-01-01

    En este trabajo se analiza la estructura microanatómica ovárica de Atlantoraja platana con el objeto de establecer las bases morfofuncionales de la biología reproductiva de la especie. El material se obtuvo de muestreos del desembarque de la flota pesquera del golfo San Matías. Las hembras fueron clasificadas según su grado madurativo en: inmaduras, en maduración y maduras. En hembras inmaduras, el ovario es blanquecino y aplanado. Microscópicamente se observan ovogonias, folículos primordial...

  19. Anatomía del corazón y las arterias branquiales aferentes de las rayas (Chondrichthyes: Batoidea)

    OpenAIRE

    Abraham Kobelkowsky

    2012-01-01

    Se selecionó el corazón y el sistema branquial aferente de Dasyatis sabina como patrón morfológico de los Batoidea. Se compararon las cámaras del corazón y la ramificación de la aorta ventral en las arterias branquiales aferentes con las correspondientes de especies representativas de otras familias de batoideos, tales como: Narcine brasiliensis (Narcinidae), Rhinobatos lentiginosus (Rhinobatidae), Raja texana (Rajidae), Urobatis jamaicensis (Urolophidae), Gymnura micrura (Gymnuridae) y Mylio...

  20. Molecular and chromosomal analysis of ribosomal cistrons in two cartilaginous fish, Taeniura lymma and Raja montagui (Chondrichthyes, Batoidea).

    Science.gov (United States)

    Rocco, L; Costagliola, D; Fiorillo, M; Tinti, F; Stingo, V

    2005-03-01

    We used silver nitrate staining, CMA3 and FISH to study the chromosomal localization of both the major ribosomal genes and the nucleolar organizer regions as well as that of the minor ribosomal genes (5S rDNA) in two species of Batoidea, Taeniura lymma (Dasyatidae) and Raja montagui (Rajidae). In both species, all the metaphases examined showed the presence of multiple NOR-bearing sites, while the gene for 5S rRNA proved to be localized on two chromosome pairs. Furthermore, one of the two 5S rDNA sites in T. lymma was shown to be co-localized with the major ribosomal cluster. The presence of multiple nucleolar organizer regions in the two species might be interpreted as being the result of intraspecific polymorphisms, or as a phenomenon of the amplified transposition of mobile elements of the genome. We also determined the nucleotide sequence of the 5S rRNA gene, consisting of 564 bp in R. montagui and 612 bp in T. lymma. We also found TATA-like and (TGC)n trinucleotides, (CA)n dinucleotides and (GTGA)n tetranucleotides, which probably influence gene regulation.

  1. Morphological study of the oviductal gland in the smallnose fanskate Sympterygia bonapartii (Müller and Henle, 1841) (Chondrichthyes, Rajidae)

    OpenAIRE

    EJ. Galíndez; MC. Díaz-Andrade; MS. Avaca; S. Estecondo

    2010-01-01

    The oviductal gland is an exclusive structure of cartilaginous fishes that produces the egg jelly, forms the tertiary egg envelopes and stores sperm. The biological importance of this structure is related to the special features of the reproductive strategy of the group and to its phylogeny, considering that egg-laying is the ancestral condition in this fish (Dulvy and Reynolds, 1997). This gland of the smallnose fanskate shows four morphofunctional zones. The lining epithelium along the glan...

  2. DNA barcoding unveils skate (Chondrichthyes: Rajidae species diversity in ‘ray’ products sold across Ireland and the UK

    Directory of Open Access Journals (Sweden)

    Andrew Mark Griffiths

    2013-08-01

    Full Text Available Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba. Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of “skate” or “ray”. The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., “winged” and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura, spotted ray (Raja montagui, thornback ray (Raja clavata, cuckoo ray (Leucoraja naevus small-eyed ray (Raja microocellata and shagreen ray (Leucoraja fullonica. Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a single retailer chain labelled their wings as originating from three smaller-growing species (generally to be considered of lower conservation concern; of the six samples analysed from this company a third were mislabelled and originated from the thornback ray (a larger species that is currently undergoing population declines.

  3. A New Paleozoic Symmoriiformes (Chondrichthyes) from the Late Carboniferous of Kansas (USA) and Cladistic Analysis of Early Chondrichthyans

    Science.gov (United States)

    Pradel, Alan; Tafforeau, Paul; Maisey, John G.; Janvier, Philippe

    2011-01-01

    Background The relationships of cartilaginous fishes are discussed in the light of well preserved three-dimensional Paleozoic specimens. There is no consensus to date on the interrelationship of Paleozoic chondrichthyans, although three main phylogenetic hypotheses exist in the current literature: 1. the Paleozoic shark-like chondrichthyans, such as the Symmoriiformes, are grouped along with the modern sharks (neoselachians) into a clade which is sister group of holocephalans; 2. the Symmoriiformes are related to holocephalans, whereas the other Paleozoic shark-like chondrichthyans are related to neoselachians; 3. many Paleozoic shark-like chondrichthyans, such as the Symmoriiformes, are stem chondrichthyans, whereas stem and crown holocephalans are sister group to the stem and crown neoselachians in a crown-chondrichthyan clade. This third hypothesis was proposed recently, based mainly on dental characters. Methodology/Principal Findings On the basis of two well preserved chondrichthyan neurocrania from the Late Carboniferous of Kansas, USA, we describe here a new species of Symmoriiformes, Kawichthys moodiei gen. et sp. nov., which was investigated by means of computerized X-ray synchrotron microtomography. We present a new phylogenetic analysis based on neurocranial characters, which supports the third hypothesis and corroborates the hypothesis that crown-group chondrichthyans (Holocephali+Neoselachii) form a tightly-knit group within the chondrichthyan total group, by providing additional, non dental characters. Conclusions/Significance Our results highlight the importance of new well preserved Paleozoic fossils and new techniques of observation, and suggest that a new look at the synapomorphies of the crown-group chondrichthyans would be worthwhile in terms of understanding the adaptive significance of phylogenetically important characters. PMID:21980367

  4. Posvjashenije Eve / Mark Levin

    Index Scriptorium Estoniae

    Levin, Mark

    2000-01-01

    Kahest lavastusest : Vene Draamateatri monoetendusest Dario Fo/F.Rame "Ootan sind, kallim" Ljubov Agapovaga, lavastaja Irina Tomingas ja Moskva Vahtangovi nim. Teatri etendusest E. Schmitti "Pühendus Eevale", lavastaja Sergei Jashin

  5. Posvjashenije Eve / Mark Levin

    Index Scriptorium Estoniae

    Levin, Mark

    2000-01-01

    Kahest lavastusest : Vene Draamateatri monoetendusest Dario Fo/F.Rame "Ootan sind, kallim" Ljubov Agapovaga, lavastaja Irina Tomingas ja Moskva Vahtangovi nim. Teatri etendusest E. Schmitti "Pühendus Eevale", lavastaja Sergei Jashin

  6. Vaikne Ö taaselustus

    Index Scriptorium Estoniae

    2008-01-01

    15. augustil sai Võsu rannaklubis muuhulgas vaadata filmi "Nukitsamees" ja kuulata Rakvere linnanoorte teatritrupi noori lugemas Eric-Emmanuel Schmitt'i raamatut "Härra Ibrahim ja Koraani õied". Ürituse eestvedaja on Kaire Leemet

  7. Vaikne Ö taaselustus

    Index Scriptorium Estoniae

    2008-01-01

    15. augustil sai Võsu rannaklubis muuhulgas vaadata filmi "Nukitsamees" ja kuulata Rakvere linnanoorte teatritrupi noori lugemas Eric-Emmanuel Schmitt'i raamatut "Härra Ibrahim ja Koraani õied". Ürituse eestvedaja on Kaire Leemet

  8. 50 CFR 300.181 - Definitions.

    Science.gov (United States)

    2010-10-01

    ..., which is an animal of the Linnaean taxonomic superorder Selachimorpha, subclass Elasmobranchii, class Chondrichthyes. Southern bluefin tuna means the species Thunnus maccoyii found in any ocean area....

  9. [An intriguing model for 5S rDNA sequences dispersion in the genome of freshwater stingray Potamotrygon motoro (Chondrichthyes: Potamotrygonidae)].

    Science.gov (United States)

    Cruz, V P; Oliveira, C; Foresti, F

    2015-01-01

    5S rDNA genes of the stingray Potamotrygon motoro were PCR replicated, purified, cloned and sequenced. Two distinct classes of segments of different sizes were obtained. The smallest, with 342 bp units, was classified as class I, and the largest, with 1900 bp units, was designated as class II. Alignment with the consensus sequences for both classes showed changes in a few bases in the 5S rDNA genes. TATA-like sequences were detected in the nontranscribed spacer (NTS) regions of class I and a microsatellite (GCT) 10 sequence was detected in the NTS region of class II. The results obtained can help to understand the molecular organization of ribosomal genes and the mechanism of gene dispersion.

  10. Populations analysis of the Brazilian Sharpnose Shark Rhizoprionodon lalandii (Chondrichthyes: Carcharhinidae on the São Paulo coast, Southern Brazil: inferences from mt DNA sequences

    Directory of Open Access Journals (Sweden)

    Fernando Fernandes Mendonça

    Full Text Available Sharks of the genus Rhizoprionodon can be considered some of the most important predators along the trophic coastal marine ecosystems and represent an important economic resource for the small-scale fisheries, especially on the Brazilian coastline. In order to analyze the population structure of the shark Rhizoprionodon lalandii of São Paulo, Southeastern coast of Brazil, levels of genetic diversity were identified by nucleotide sequence analyses of the mitochondrial DNA control region. The results obtained from this study present moderate values of haplotype diversity and low nucleotide diversity. Although the AMOVA tests (ΦST = 0.08394, P < 0.01 had shown slightly differences among the studied samples, evidence for the occurrence of population structuring was not found, which may be a general feature of sharks living in coastal areas.

  11. A partial braincase and other skeletal remains of Oligocene angel sharks (Chondrichthyes, Squatiniformes) from northwest Belgium, with comments on squatinoid taxonomy

    NARCIS (Netherlands)

    Mollen, F.H.; Bakel , van B.W.M.; Jagt, J.W.M.

    2016-01-01

    A detailed redescription of a chondrocranium from the basal Boom Clay Formation (Rupelian, Upper Oligocene) at the SVK clay pit, Sint-Niklaas (province of Oost-Vlaanderen, Belgium), previously assigned to the sawshark Pristiophorus rupeliensis, is presented. The chondrocranium is re-identified as th

  12. A new Middle Miocene selachian assemblage (Chondrichthyes, Elasmobranchii) from the Central Paratethys (Nyirád, Hungary): implications for temporal turnover and biogeography

    Science.gov (United States)

    Szabó, Márton; Kocsis, László

    2016-12-01

    A new Middle Miocene (Langhian - early Serravallian) assemblage with shark and ray teeth from Nyirád (Hungary, Transdanubia, Veszprém County) consists of nine families, with 15 different species. The assemblage shares many common genera with other Middle Miocene assemblages in the Paratethys (Notorynchus, Carcharias, Otodus, Cosmopolitodus, Hemipristis, Galeocerdo, Carcharhinus, and Aetobatus), and reflects a subtropical climate and a close connection with the Mediterranean Sea. However, a detailed faunal compilation of Miocene selachians reveals that several taxa that were still present in the Mediterranean or lived in the Paratethys during the Lower Miocene disappeared or became very rare by the Middle Miocene in the Central Paratethys (e.g., Isistius, Centrophorus, Mitsukurina, Carcharoides, Parotodus, Alopias). The taxa that went locally extinct in the Paratethys are mainly represented by deep-water or pelagic forms. Their disappearance is most probably related to the gradual separation of the Paratethys from the Mediterranean. The common presence of some large, rather pelagic sharks (e.g., Otodus, Cosmopolitodus) in the Central Paratethys during the Middle Miocene is explained here by the widespread occurrence of their potential prey represented by marine mammals (e.g., whales and dolphins).

  13. Acanthobothrium nicoyaense n. sp. (Eucestoda: Tetraphyllidea: Onchobothriidae) in Aetobatus narinari (Euphrasen) (Chondrichthyes: Myliobatiformes: Myliobatidae) from the Gulf of Nicoya, Costa Rica.

    Science.gov (United States)

    Brooks, D R; McCorquodale, S

    1995-04-01

    A new species of Acanthobothrium in Aetobatus narinari from the Gulf of Nicoya, Costa Rica, most closely resembles Acanthobothrium colombianum in the same host and A. urotrygoni in Urotrygon venezuelae from Cartagena, Colombia, by having relatively few proglottides per strobila, spinose cephalic peduncles, bothridial margins free at their posterior ends, and irregularly shaped rather than spherical or elongate cirrus sacs. Acanthobothrium colombianum differs from the new species by being as much as 35 mm rather than no more than 4.7 mm long and by having 31-48 rather than 13-19 proglottides, an average of 46 rather than 15 testes per proglottis, and bothridial hooks averaging 185 microns rather than 137 microns in total length. Acanthobothrium urotrygoni differs from the new species by being as much as 15 mm rather than no more than 4.7 mm long and by having V-shaped rather than H-shaped ovaries, bothridial hooks averaging 95 microns rather than 137 microns in total length, by having an average of 28 rather than 15 testes per proglottis, and by having poral ovarian arms extending anteriorly to the posterior margin of the cirrus sac and aporal arms extending to the lateral margin of the cirrus sac.

  14. Escherbothrium molinae n. gen. et n. sp. (Eucestoda: Tetraphyllidea: Triloculariidae) in Urotrygon chilensis (Chondrichthyes: Myliobatiformes: Urolophidae) from the Gulf of Nicoya, Costa Rica.

    Science.gov (United States)

    Berman, R; Brooks, D R

    1994-10-01

    Cestodes collected in spiral valves of the stingray Urotrygon chilensis from the Pacific coast of Costa Rica represent an undescribed species of Tetraphyllidea. By possessing more than 2 loculi as well as an apical sucker on each bothridium, the new species is diagnosably distinct from all other tetraphyllidean genera; therefore, a new genus is proposed for it. The new species also possesses globular structures irregularly arranged on the surface of the bothridia. We found similar structures on the bothridial faces of Trilocularia acanthiaevulgaris, possibly indicating phylogenetic relationships with the new species. This possibility is enhanced by the observation that the bothridia of T. acanthiaevulgaris comprise 2 loculi and an apical sucker, rather than 3 loculi.

  15. Comparisons of dental morphology in river stingrays (Chondrichthyes: Potamotrygonidae) with new fossils from the middle Eocene of Peruvian Amazonia rekindle debate on their evolution.

    Science.gov (United States)

    Adnet, Sylvain; Salas Gismondi, Rodolfo; Antoine, Pierre-Olivier

    2014-01-01

    Endemic South American river stingrays (Potamotrygonidae), which include the most diversified living freshwater chondrichthyans, were conspicuously absent from pre-Neogene deposits in South America despite the fact that recent phylogenetic analyses strongly suggest an older origination for this clade. To date, the rare representatives of this family were mostly represented by ambiguous isolated remains. Here, we report 67 isolated fossil teeth of a new obligate freshwater dasyatoid (Potamotrygon ucayalensis nov. sp) from the fossiliferous level CTA-27 (Yahuarango Formation), near Contamana, in the Peruvian Amazonia. We assigned this sample to a new representative of Potamotrygon by comparison with numerous fresh jaws of living specimens of Potamotrygonidae, thus providing the first detailed review of dental morphology for this poorly understood clade. These new fossils fill a long stratigraphic gap by extending the family range down to the middle Eocene (~41 Mya). Moreover, the relative modernity and diversity in tooth morphology among Eocene freshwater stingrays (including Potamotrygon ucayalensis nov. sp. and coeval North American dasyatoids) indicate that the hypothetically marine ancestor of potamotrygonids probably invaded the rivers earlier than in the middle Eocene. The first potamotrygonids and affiliates were possibly more generalized and less endemic than now, which is consistent with an opportunistic filling of vacated ecospace.

  16. A new species of Ischyodus (Chondrichthyes: Holocephali: Callorhynchidae) from Upper Maastrichtian Shallow marine facies of the Fox Hills and Hell Creek Formations, Williston basin, North Dakota, USA

    Science.gov (United States)

    Hoganson, J.W.; Erickson, J.M.

    2005-01-01

    A new species of chimaeroid, Ischyodus rayhaasi sp. nov., is described based primarily upon the number and configuration of tritors on palatine and mandibular tooth plates. This new species is named in honour of Mr Raymond Haas. Fossils of I. rayhaasi have been recovered from the Upper Maastrichtian Fox Hills Formation and the Breien Member and an unnamed member of the Hell Creek Formation at sites in south-central North Dakota and north-central South Dakota, USA. Ischyodus rayhaasi inhabited shallow marine waters in the central part of the Western Interior Seaway during the latest Cretaceous. Apparently it was also present in similar habitats at that time in the Volga region of Russia. Ischyodus rayhaasi is the youngest Cretaceous species Ischyodus known to exist before the Cretaceous/Tertiary extinction, and the species apparently did not survive that event. It was replaced by Ischyodus dolloi, which is found in the Paleocene Cannonball Formation of the Williston Basin region of North Dakota and is widely distributed elsewhere. ?? The Palaeontological Association.

  17. Ecological patterns, distribution and population structure of Prionace glauca (Chondrichthyes: Carcharhinidae) in the tropical-subtropical transition zone of the north-eastern Pacific.

    Science.gov (United States)

    Vögler, Rodolfo; Beier, Emilio; Ortega-García, Sofía; Santana-Hernández, Heriberto; Valdez-Flores, J Javier

    2012-02-01

    Regional ecological patterns, distribution and population structure of Prionace glauca were analyzed based on samples collected on-board two long-line fleets operating in oceanic waters (1994-96/2000-02) and in coastal oceanic waters (2003-2009) of the eastern tropical Pacific off México. Generalized additive models were applied to catch per unit of effort data to evaluate the effect of spatial, temporal and environmental factors on the horizontal distribution of the life stages (juvenile, adult) and the sexes at the estimated depth of catch. The presence of breeding areas was explored. The population structure was characterized by the presence of juveniles' aggregations and pregnant females towards coastal waters and the presence of adult males' aggregations towards oceanic waters. The species exhibited horizontal segregation by sex-size and vertical segregation by sex. Distribution of the sex-size groups at oceanic waters was seasonally affected by the latitude; however, at coastal oceanic waters mainly females were influenced by the longitude. Latitudinal changes on the horizontal distribution were coupled to the seasonal forward and backward of water masses through the study area. Adult males showed positive relationship with high temperatures and high-salinities waters (17.0°-20.0 °C; 34.2-34.4) although they were also detected in low-salinities waters. The distribution of juvenile males mainly occurred beyond low temperatures and low-salinities waters (14.0°-15.0 °C; 33.6-34.1), suggesting a wide tolerance of adult males to explore subartic and subtropical waters. At oceanic areas, adult females were aggregated towards latitudes glauca. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Reproductive biology of the guitarfish Rhinobatos percellens (Chondrichthyes, Rhinobatidae) from the São Paulo Coast, Brazil, western South Atlantic Ocean.

    Science.gov (United States)

    Rocha, F; Gadig, O B F

    2013-01-01

    The reproductive biology of the guitarfish Rhinobatos percellens was studied from 751 specimens caught by bottom pair trawlers off the coast of São Paulo, Brazil, between c. 24° 00' S; 45° 15' W and c. 25° 10' S; 47° 52' W, from September 2007 to August 2009. The total length (L(T)) and total mass (M(T)) relationship for males and females combined was M(T) = 1·29E-06 L(T) (3·15) (r = 0·99, n = 751). The mean L(T) of sexually mature specimens was 548 mm for males and 583 mm for females. Clasper growth was allometric and showed three distinct phases. Most claspers were calcified in specimens of c. 550 mm L(T). The mean diameter of the largest oocyte was 29·8 mm, the mean ovarian fecundity was seven oocytes and ovulation occurred between August and November. Uterine fecundity ranged from two to 13 embryos (mean of five embryos). Larger females had higher litter sizes and larger embryos; the size-at-birth was c. 200 mm L(T). The hepato-somatic index oscillated seasonally for males and females; the gonado-somatic index had little variation in males, but varied seasonally in females. The presence of many non-pregnant adult females and of encapsulated eggs during two consecutive seasons suggests a resting period between gestations and the possibility of diapause.

  19. A partial braincase and other skeletal remains of Oligocene angel sharks (Chondrichthyes, Squatiniformes) from northwest Belgium, with comments on squatinoid taxonomy

    NARCIS (Netherlands)

    Mollen, F.H.; Bakel , van B.W.M.; Jagt, J.W.M.

    A detailed redescription of a chondrocranium from the basal Boom Clay Formation (Rupelian, Upper Oligocene) at the SVK clay pit, Sint-Niklaas (province of Oost-Vlaanderen, Belgium), previously assigned to the sawshark Pristiophorus rupeliensis, is presented. The chondrocranium is re-identified as th

  20. Distribution of radioactivity in the chondrichthyes Squalus acanthias and the osteichthyes salmo gairdneri following intragastric administration of (9-/sup 14/C)phenanthrene

    Energy Technology Data Exchange (ETDEWEB)

    Solbakken, J.E.; Palmork, K.H.

    1980-12-01

    The fate of polycyclic hydrocarbons (PAH) in marine animals has received increasing attention in the last decade. The present studies dealing with spiny dogfish (Squalus acanthias) and rainbow trout (Salmo gairdneri) are part of a series of experiments with different marine organisms. All the experiments were performed under the same laboratory conditions using intragastric administration of the PAH-component, /sup 14/C-labelled phenanthrene. Thus it is possible to compare species differences of disposition of PAH in various marine organisms. The most pronounced differences in the disposition of phenanthrene between bony fish and cartilaginous fish in our studies are that the maximum value of radioactivity in the liver of cartilaginous fish occurred several days later than the corresponding value in bony fish. Furthermore, the radioactivity in cartilaginous fish was retained at a high level beyond 672 h (28 days), a time at which the radioactivity in bony fish is near the background values.

  1. A partial braincase and other skeletal remains of Oligocene angel sharks (Chondrichthyes, Squatiniformes) from northwest Belgium, with comments on squatinoid taxonomy

    NARCIS (Netherlands)

    Mollen, F.H.; Bakel , van B.W.M.; Jagt, J.W.M.

    2016-01-01

    A detailed redescription of a chondrocranium from the basal Boom Clay Formation (Rupelian, Upper Oligocene) at the SVK clay pit, Sint-Niklaas (province of Oost-Vlaanderen, Belgium), previously assigned to the sawshark Pristiophorus rupeliensis, is presented. The chondrocranium is re-identified as

  2. New name for Progrillotia dollfusi Carvajal et Rego, 1983 (Cestoda: Trypanorhyncha): description of adults from Squatina guggenheim (Chondrichthyes: Squatiniformes) off the coast of Argentina.

    Science.gov (United States)

    Menoret, Adriana; Ivanov, Verónica A

    2009-12-01

    Examination of the type material of Progrillotia dollfusi Carvajal et Rego, 1983, and of new specimens recently collected off the coast of Argentina (including plerocerci from 10 species of teleosts and adults from Squatina guggenheim Marini), allowed a detailed redescription of this species and the evaluation of its current taxonomic status. The following characters that have been treated inconsistently by different authors have been herein corrected or confirmed: band of hooklets on external surface restricted to the base of the tentacle, external surface of metabasal region with 3-5 intercalary hooks arranged in a single row merging immediately to a cluster of 3-4 hooklets arranged in two rows; retractor muscle originating in the posterior third of the bulb, hollow hooks, and posterior margin of bothria notched. These features along with the presence of postovarian testes in the adults clearly confirm the placement of P. dollfusi in the genus Grillotia Guiart, 1927. In order to avoid the homonymy with Grillotia dollfusi Carvajal, 1971, a new name, Grillotia carvajalregorum nom. n., is proposed. This species differs from the 16 valid species in the genus in the combination of the following characters: number and morphology of hooks in principal rows in proximal metabasal region of the tentacle, number and distribution of intercalary hooks, presence of clusters of hooklets, extent of band of hooklets on external surface of basal armature, site of origin of the retractor muscle, and features of the terminal genitalia. The present study describes the plerocerci and adult worms, and provides detailed description of the microthrix pattern and histology of this species for the first time.

  3. A partial braincase and other skeletal remains of Oligocene angel sharks (Chondrichthyes, Squatiniformes) from northwest Belgium, with comments on squatinoid taxonomy

    OpenAIRE

    Mollen, F.H.; Bakel, van, P.J.T.; Jagt, J.W.M.

    2016-01-01

    A detailed redescription of a chondrocranium from the basal Boom Clay Formation (Rupelian, Upper Oligocene) at the SVK clay pit, Sint-Niklaas (province of Oost-Vlaanderen, Belgium), previously assigned to the sawshark Pristiophorus rupeliensis, is presented. The chondrocranium is re-identified as that of an angel shark (Squatinidae), based on comparative anatomy of extant Squatina, inclusive of CT scans of Squatina africana, S. australis, S. dumeril, S. guggenheim and S. squatina, with differ...

  4. A new species of Neotropical freshwater stingray of the genus Potamotrygon Garman, 1877 from the Río Madrede Díos, Peru (Chondrichthyes: Potamotrygonidae

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    João Paulo C.B. da Silva

    2011-01-01

    Full Text Available Potamotrygon tatianae sp. nov., is described from Río Madre de Díos, Peru, upper Rio Madeira basin. The new species is distinguished from all congeners by a unique combination of characters, including its dorsal color pattern formed by a relatively slender, highly convoluted, beige to dark brown vermicular pattern, a single row of dorsal tail spines, and a relatively longer tail posterior to caudal stings. Potamotrygon tatianae sp. nov., occurs sympatrically with other species of Potamotrygon (P. falkneri, P. orbignyi and P. motoro. From the similar species P. falkneri, P. tatianae sp. nov., is further distinguished by the absence of circular, reniform, and oval spots, by its proportionally much longer tail, by having dorsal tail spines in one irregular row, and by features of the ventral lateral-line canal, dermal denticles and neurocranium. From P. orbignyi, the new species is distinct by lacking a reticulate pattern on dorsal disc and by the presence of two angular cartilages. From P. motoro, P. tatianae sp. nov., is further separated by the lack of ocelli formed by strong black concentric rings, by the more flattened aspect of its head and disc, and by having smaller and more numerous teeth. The discovery of a new species that so closely resembles a congeneric form in color pattern, a feature highly variable within the latter, highlights the importance of examining large series of individuals and of detailed morphological analyses in revealing the potentially highly cryptic nature of the diversity within the family.

  5. An unusual, dwarf new species of Neotropical freshwater stingray, Plesiotrygon nana sp. nov., from the upper and mid Amazon basin: the second species of Plesiotrygon (Chondrichthyes: Potamotrygonidae

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    Marcelo R. de Carvalho

    2011-01-01

    Full Text Available A new species of the relatively poorly known Neotropical freshwater stingray genus Plesiotrygon Rosa, Castello & Thorson, 1987 is described from the main channel and smaller tributaries (Ríos Itaya and Pachitea of the upper Amazon basin in Peru. The first specimen to be collected, however, was from much farther east in Rio Solimões in 1996, just down-river from Rio Purus (specimen unavailable for this study. Plesiotrygon nana sp. nov., is a very distinctive and unusually small species of freshwater stingray (Potamotrygonidae, described here mostly from three specimens representing different size classes and stages of sexual maturity. Plesiotrygon nana sp. nov., is distinguished from its only congener, P. iwamae Rosa, Castello & Thorson, 1987, by numerous unique features, including: dorsal coloration composed of very fine rosettes or a combination of spots and irregular ocelli; very circular disc and snout; very small and less rhomboidal spiracles; short snout and anterior disc region; narrow mouth and nostrils; denticles on dorsal tail small, scattered, not forming row of enlarged spines; adult and preadult specimens with significantly fewer tooth rows; fewer caudal vertebrae; higher total pectoral radials; very small size, probably not surpassing 250 mm disc length or width, males maturing sexually at around 180 mm disc length and 175 mm disc width; distal coloration of tail posterior to caudal stings usually dark purplish-brown; and features of the ventral lateral-line canals (hyomandibular canal very narrow, infraorbital and supraorbital canals not undulated, supraorbital and infraorbital loops small and narrow, supraorbital loop very short, not extending posteriorly to level of mouth, jugular and posterior infraorbital canals short, not extending caudally to first gill slits, subpleural loop very narrow posteriorly; absence of anterior and posterior subpleural tubules. To provide a foundation for the description of P. nana sp. nov., morphological variation in P. iwamae was examined based on all type specimens as well as newly collected and previously unreported material. Two specimens topotypic with the male paratype of P. nana sp. nov., referred to here as Plesiotrygon cf. iwamae, are also reported. Relationships of the new species to P. iwamae are discussed; further characters indicative of Plesiotrygon monophyly are proposed, but the genus may still not be valid. Plesiotrygon nana sp. nov., is commercialized with some regularity in the international aquarium trade from Iquitos (Peru, an alarming circumstance because nothing is known of its biology or conservation requirements.

  6. Potamotrygon rex, a new species of Neotropical freshwater stingray (Chondrichthyes: Potamotrygonidae) from the middle and upper rio Tocantins, Brazil, closely allied to Potamotrygon henlei (Castelnau, 1855).

    Science.gov (United States)

    Carvalho, Marcelo R De

    2016-08-16

    A systematic revision of the rio Tocantins stingrays has confirmed the occurrence of a new species of Potamotrygon first discovered more than two decades ago but which lacked material for a thorough description. Field surveys since undertaken in the middle and upper rio Tocantins have assembled significant material that forms the basis of an ongoing revision of the diverse Tocantins potamotrygonid assemblage. Potamotrygon rex, sp. nov., is a very large, "black stingray" species from the mid and upper rio Tocantins that is closely related to P. henlei (Castelnau), which occurs in the lower Tocantins basin and in rio Araguaia; both species do not co-occur. Potamotrygon rex, sp. nov., has a unique blackish to dark brown dorsal color with numerous small, yellow to orange irregular spots usually forming distinct clusters on dorsal disc, with ocelli in center of clusters on posterior and outer disc, dorsal tail also with clusters but lateral tail with ocelli, and a dark brownish to gray color covering most of ventral surface except nasoral region, gill slits and anterior snout in some specimens, with small whitish spots on ventral disc, pelvic fins and tail. Potamotrygon rex, sp. nov., can be further distinguished by its broad pelvic-fin apices, lack of labial grooves, irregular double row of dorsal tail thorns, and in having two angular cartilages associated with each hyomandibula. Potamotrygon rex, sp. nov., P. henlei, P. leopoldi Castex & Castello, and another new Potamotrygon species from the rio Tapajós (in description) form a species-group (the "black stingrays") occurring in rivers draining the central Brazilian shield, characterized by their black to dark brown but highly ornate dorsal color, wide pelvic fins with broadly convex apices, among other features. Potamotrygon rex, sp. nov., is the 25th species of Potamotrygon, and highlights that very large new species of fishes still await discovery and description in the Neotropical region.

  7. Ontogenetic scaling of caudal fin shape in Squalus acanthias (Chondrichthyes, Elasmobranchii): a geometric morphometric analysis with implications for caudal fin functional morphology.

    Science.gov (United States)

    Reiss, Katie L; Bonnan, Matthew F

    2010-07-01

    The shark heterocercal caudal fin and its contribution to locomotion are of interest to biologists and paleontologists. Current hydrodynamic data show that the stiff dorsal lobe leads the ventral lobe, both lobes of the tail are synchronized during propulsion, and tail shape reflects its overall locomotor function. Given the difficulties surrounding the analysis of shark caudal fins in vivo, little is known about changes in tail shape related to ontogeny and sex in sharks. A quantifiable analysis of caudal fin shape may provide an acceptable proxy for inferring gross functional morphology where direct testing is difficult or impossible. We examined ontogenetic and sex-related shape changes in the caudal fins of 115 Squalus acanthias museum specimens, to test the hypothesis that significant shape changes in the caudal fin shape occur with increasing size and between the sexes. Using linear and geometric morphometrics, we examined caudal shape changes within the context of current hydrodynamic models. We found no statistically significant linear or shape difference between sexes, and near-isometric scaling trends for caudal dimensions. These results suggest that lift and thrust increase linearly with size and caudal span. Thin-plate splines results showed a significant allometric shape change associated with size and caudal span: the dorsal lobe elongates and narrows, whereas the ventral lobe broadens and expands ventrally. Our data suggest a combination of caudal fin morphology with other body morphology aspects, would refine, and better elucidate the hydrodynamic factors (if any) that underlie the significant shape changes we report here for S. acanthias.

  8. Comparative myology of the mandibular and hyoid arches of sharks of the order hexanchiformes and their bearing on its monophyly and phylogenetic relationships (Chondrichthyes: Elasmobranchii).

    Science.gov (United States)

    Soares, Mateus C; de Carvalho, Marcelo R

    2013-02-01

    The order Hexanchiformes currently comprises two families, Chlamydoselachidae (frilled sharks) and Hexanchidae (six- and seven-gill sharks), but its monophyly and relationships with other elasmobranchs are still discussed. Previous studies of hexanchiforms addressing these issues were based mainly on external morphology, teeth, skeletal features, and molecular data, whereas the employment of characters derived from variations in muscles has not been significantly explored. Dissections of four species of Hexanchiformes (including Chlamydoselachus anguineus) are reported here describing the mandibular (musculus adductor mandibulae dorsalis, m. adductor mandibulae ventralis, m. levator labii superioris, m. intermandibularis, and m. constrictor dorsalis) and hyoidean (m. constrictor hyoideus dorsalis and ventralis) arch muscles. Our results provide new data concerning the relationships of hexanchiforms to other elasmobranchs. The m. adductor mandibulae superficialis is described and illustrated in C. anguineus, contradicting previous accounts in which is was considered absent. The anteroposterior orientation of the m. adductor mandibulae superficialis in Chlamydoselachus is similar to the pattern found in hexanchids, squaloids, and hypnosqualeans (including batoids), suggesting it was secondarily lost in Echinorhinus. This muscle therefore provides further support for the inclusion of the Chlamydoselachidae and Hexanchidae in the Squalomorphi, and not basal to all other elasmobranchs or nested within an all-shark collective, as has been previously proposed. However, the m. adductor mandibulae superficialis originating at the jaw joint and with an aponeurotic insertion in hexanchids, squaliforms, and hypnosqualeans, may be a separate derived feature uniting these taxa. The insertion of the m. constrictor dorsalis is restricted to the postorbital articulation in hexanchids, whereas it extends farther anteriorly in C. anguineus. The insertion of the m. constrictor hyoideus dorsalis solely on the palatoquadrate is found exclusively in the Hexanchidae. We conclude that no specific pattern of mandibular or hyoid arch muscles support the monophyly of hexanchiforms (i.e., including Chlamydoselachus).

  9. A new Middle Miocene selachian assemblage (Chondrichthyes, Elasmobranchii from the Central Paratethys (Nyirád, Hungary: implications for temporal turnover and biogeography

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    Szabó Márton

    2016-12-01

    Full Text Available A new Middle Miocene (Langhian - early Serravallian assemblage with shark and ray teeth from Nyirád (Hungary, Transdanubia, Veszprém County consists of nine families, with 15 different species. The assemblage shares many common genera with other Middle Miocene assemblages in the Paratethys (Notorynchus, Carcharias, Otodus, Cosmopolitodus, Hemipristis, Galeocerdo, Carcharhinus, and Aetobatus, and reflects a subtropical climate and a close connection with the Mediterranean Sea. However, a detailed faunal compilation of Miocene selachians reveals that several taxa that were still present in the Mediterranean or lived in the Paratethys during the Lower Miocene disappeared or became very rare by the Middle Miocene in the Central Paratethys (e.g., Isistius, Centrophorus, Mitsukurina, Carcharoides, Parotodus, Alopias. The taxa that went locally extinct in the Paratethys are mainly represented by deep-water or pelagic forms. Their disappearance is most probably related to the gradual separation of the Paratethys from the Mediterranean. The common presence of some large, rather pelagic sharks (e.g., Otodus, Cosmopolitodus in the Central Paratethys during the Middle Miocene is explained here by the widespread occurrence of their potential prey represented by marine mammals (e.g., whales and dolphins.

  10. Heavy metal concentrations in edible muscle of whitecheek shark, Carcharhinus dussumieri (elasmobranchii, chondrichthyes) from the Persian Gulf: A food safety issue.

    Science.gov (United States)

    Adel, Milad; Oliveri Conti, Gea; Dadar, Maryam; Mahjoub, Masoud; Copat, Chiara; Ferrante, Margherita

    2016-11-01

    Together with several health benefits, fish meat could lead to heavy metal intoxication of consumers. In this study, we discuss Zn, Cu, Pb, Hg and Cd concentrations in fillets of forty specimens of Carcharhinus dussumieri, analyzed with atomic adsorption spectroscopy (AAS). The potential human health risks due to consumption of C. dussumieri was assessed by estimating average daily intake (EDI) and target hazard quotient (THQ) of metals. The average concentrations of metals measured in this study were (ppm dry weight): Cu 7.49 ± 0.25; Zn 3.47 ± 0.26; Pb 0.12 ± 0.03; Hg 0.028 ± 0.02; Cd 0.11 ± 0.03. Our results showed that no metal exceeded the EC and FAO limits. Cu and Cd accumulate in muscles with a body length (age)-dependent manner. The exposure daily intake of all toxic metals analyzed was found lower than the PTDI provided by WHO and the THQ resulted lower than 1, suggesting no risk for human health derived from consumption.

  11. Size composition, monthly condition factor and morphometrics for fishery-dependent samples of Rioraja agassizi (Chondrichthyes: Rajidae, off Santos, Southeast Brazil

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    M. Cristina Oddone

    Full Text Available Specimens of Rioraja agassizi were collected monthly off Santos, Southeast Brazil, between latitudes 23º37'S and 27º40'S, from March, 2005 to March, 2006. A total number of 278 males and 1023 females were captured. Observed depth range was 10-120 m, being the species absent above 120 m. Sex ratio significantly favored females. The entire length range of R. agassizi was observed. Females ranged in length from 16.0 to 59.4 cm and males from 13.0 to 47.2 cm. Mean female length was significantly higher than that of males. For grouped length distributions, asymmetry patterns were observed in both sexes. Length-width functions were sexually dimorphic. Males with lengths 3 (positive allometry. The monthly variation of the condition factor showed significant differences in both sexes.

  12. Commercial catches, reproduction and feeding habits of Raja asterias (Chondrichthyes: Rajidae in a coastal area of the Tyrrhenian Sea (Italy, northern Mediterranean

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    Marino VACCHI

    2007-06-01

    Full Text Available A total of 52 “rapido” (towed toothed beam gears trawls were monitored in late winter-summer of the 1999-2000 period to assess the R. asterias size structure at this time of higher yields as well as 36 fishing operations performed by “volantina” (trawl nets with fairly high vertical opening during distinct seasons on the continental shelf off the fishing harbour of Fiumicino (central western Italy to gain data also for that gear. Daily yields recorded for the only boat locally authorised to use “rapido” nets gave median values of 32.0 individuals and 24.35 kg vs. 2.5 rays and 2.80 kg for trawlers fishing at the same time. Comparison of the body sizes at which 50% of the skates had been found mature in our samples (265 gonads examined showed that most specimens caught by the “rapido” nets were in their juvenile stage. Examination of stomach contents from 129 skates confirmed previous reports that they mainly feed on crustaceans and bony fish and the role of the latter in the diet progressively increases as R. asterias specimens grow older and larger.

  13. Geo(Im)pulseBite marks on early Holocene Tursiops truncatus fossils from the North Sea indicate scavenging by rays (Chondrichthyes, Rajidae)

    NARCIS (Netherlands)

    Netten, H.H. van; Reumer, J.W.F.

    2010-01-01

    A number of Tursiops truncatus mandibles in the collection of fossil marine mammals in the Rotterdam Natural History Museum have marks consisting of several parallel linear grooves. These marks are also found on four atlas complexes, a scapula and on one vertebra. The hypothesis that they are bite m

  14. Clave de identificación de las rayas del litoral marítimo de Argentina y Uruguay (Chondrichthyes, Familia Rajidae).

    OpenAIRE

    Cousseau, M.B.; Figueroa, D.E.; Diaz de Astarloa, J.M.

    2000-01-01

    The paper has two parts. The first part comprises and illustrated identification key of the 22 species of the Rajidae Family that authors recognize in the study area. The second part includes a design of the dorsal face, a brief description and a chart distribution given for each species. Given the fact that, with a few exceptions, all species are named skates ('rayas'), common names are suggested by the authors.

  15. Molecular organization of 5S rDNAs in Rajidae (Chondrichthyes): Structural features and evolution of piscine 5S rRNA genes and nontranscribed intergenic spacers.

    Science.gov (United States)

    Pasolini, Paola; Costagliola, Domenico; Rocco, Lucia; Tinti, Fausto

    2006-05-01

    The genomic and gene organisation of 5S rDNA clusters have been extensively characterized in bony fish and eukaryotes, providing general issues for understanding the molecular evolution of this multigene DNA family. By contrast, the 5S rDNA features have been rarely investigated in cartilaginous fish (only three species). Here, we provide evidence for a dual 5S rDNA gene system in the Rajidae by sequence analysis of the coding region (5S) and adjacent nontranscribed spacer (NTS) in five Mediterranean species of rays (Rajidae), and in a large number of piscine taxa including lampreys and bony fish. As documented in several bony fish, two functional 5S rDNA types were found here also in the rajid genome: a short one (I) and a long one (II), distinguished by distinct 5S and NTS sequences. That the ancestral piscine genome had these two 5S rDNA loci might be argued from the occurrence of homologous dual gene systems that exist in several fish taxa and from 5S phylogenetic relationships. An extensive analysis of NTS-II sequences of Rajidae and Dasyatidae revealed the occurrence of large simple sequence repeat (SSR) regions that are formed by microsatellite arrays. The localization and organization of SSR within the NTS-II are conserved in Rajiformes since the Upper Cretaceous. The direct correlation between the SSRs extension and the NTS length indicated that they might play a role in the maintenance of the larger 5S rDNA clusters in rays. The phylogenetic analysis indicated that NTS-II is a valuable systematic tool limited to distantly related taxa of Rajiformes.

  16. A Key to the Fishes of Mississippi Sound and Adjacent Waters,

    Science.gov (United States)

    1974-01-01

    through a single outlet; no operculum; head without bones visible through skin; skeleton cartilaginous ... Class Chondrichthyes (page 1) Gill openings...skeleton usually bony ... Class Osteichthyes (Page 5) CLASS CHONDRICHTHYES I Gill openings at least partly visible from side view; pectoral fins not...as leaflike filament; inner margins of pelvics not fused with tail ......................................................... Rajidae (Page 4) No

  17. First record of Hydrolagus melanophasma James, Ebert, Long & Didier, 2009 (Chondrichthyes, Chimaeriformes, Holocephali from the southeastern Pacific Ocean Primer registro de Hydrolagus melanophasma James, Ebert, Long & Didier, 2009 (Chondrichthyes, Chimaeriformes, Holocephali en el Océano Pacífico suroriental

    Directory of Open Access Journals (Sweden)

    Carlos Bustamante

    2012-03-01

    Full Text Available The eastern Pacific black ghost shark, Hydrolagus melanophasma is reported from deep waters off Chile and is described from specimens collected off Valdivia at depths of 1150 to 1720 m. This species is distinguished from all other members of the genus by its large, curved dorsal fin spine, which extends beyond the dorsal fin apex; a second dorsal fin of uniform height along the caudal peduncle; large pectoral fins extending beyond the pelvic fin insertion; and a uniform black color of the body. Catch records of this species in Chile suggest a discontinuous distribution along the continental slope of the eastern Pacific Ocean, restricted to the Middle America and Atacama trenches. These observations elevate the number of chimaeroid fishes inhabiting Chile to five species.La quimera negra del Pacífico este, Hydrolagus melanophasma es reportada desde aguas profundas frente a Chile y se describe a partir de especímenes colectados en Valdivia en profundidades ente 1150 y 1720 m. Esta especie se diferencia de los otros miembros del género por su larga y curvada espina dorsal, la cual se extiende más allá del ápice de la aleta dorsal; presenta una segunda aleta dorsal de altura uniforme a lo largo del pedúnculo caudal; grandes aletas pectorales que se proyectan sobre la inserción de las aletas pélvicas, además de su coloración negra uniforme en el cuerpo. Los registros de captura de esta especie en Chile sugieren una distribución discontinua a lo largo del talud continental del océano Pacifico este, restringido a las fosas oceánicas de Atacama y Mesoamérica. Estas observaciones aumentan a cinco el número de especies de peces Chimaeriformes que habitan aguas chilenas.

  18. Morphological study of the oviductal gland in the smallnose fanskate Sympterygia bonapartii (Müller and Henle, 1841 (Chondrichthyes, Rajidae Estudo morfológico da glândula oviductal no smallnose fanskate Sympterygia bonapartii (Müller and henle, 1841 (Chondrichthyes, Rajidae

    Directory of Open Access Journals (Sweden)

    EJ Galíndez

    2010-05-01

    Full Text Available The oviductal gland is an exclusive structure of cartilaginous fishes that produces the egg jelly, forms the tertiary egg envelopes and stores sperm. The biological importance of this structure is related to the special features of the reproductive strategy of the group and to its phylogeny, considering that egg-laying is the ancestral condition in this fish (Dulvy and Reynolds, 1997. This gland of the smallnose fanskate shows four morphofunctional zones. The lining epithelium along the gland is columnar with secretory and ciliated cells. Secretions are mucous and/or proteic according to the zone, and to their specific functions. This is the first report about the microanatomy of the female reproductive tract of S. bonapartii with evidence of sperm storage in the genus.A glândula oviductal é uma estrutura exclusiva das elasmobrânquias que produz a geléia do ovo, o envoltório terciário do ovo e armazena espermatozóides. Sua importância está relacionada com as características especiais da estratégia reprodutiva do grupo e com a filogenia destes peixes em que oviparidade é a condição ancestral (Dulvy and Reynolds, 1997. A glândula oviductal do smallnose fanskate mostra quatro zonas morfofuncionais. O revestimento em toda a glândula é epitélio colunar ciliado com células glandulares e ciliadas. As secreções são diferentes entre as zonas e relacionada com as suas funções específicas. A informação aqui exposta constitui o primeiro relato sobre a micro-anatomia do trato reprodutivo feminino de S. bonapartii com evidencias de armazenamento do esperma neste gênero.

  19. Hábitos alimentares e sobreposição trófica das raias Potamotrygon falkneri e Potamotrygon motoro (Chondrichthyes, Potamotrygonidae na planície alagável do alto rio Paraná, Brasil = Feeding habitats and trophic overlap of the freshwater stingrays Potamotrygon falkneri e Potamotrygon motoro (Chondrichthyes, Potamotrygonidae in the upper Paraná river floodplain, Brazil

    Directory of Open Access Journals (Sweden)

    Milza Celi Fedatto Abelha

    2006-07-01

    Full Text Available As raias Potamotrygon falkneri e Potamotrygon motoro foram avaliadas em relação à composição de suas dietas e a sobreposição do nicho trófico nos períodos de seca (agosto/2004 e cheia (janeiro/2005 na planície alagável do alto rio Paraná, em três estações de coleta próximas à ilha Mutum. Foram analisados 49 conteúdos estomacais de P. falkneri e 16 de P. motoro, obtidos de espécimes capturados através de pesca com anzol, fisga (arpão e espinhel. Os conteúdos estomacais foram analisados de acordo com os métodos de freqüência volumétrica e de ocorrência. A similaridade da dieta foi quantificada pelo índicede sobreposição de Pianka. As espécies revelaram flexibilidade alimentar, com ambas consumindo predominantemente moluscos na cheia, enquanto na seca a dieta de P. falkneri foi composta principalmente por peixes e a de P. motoro por insetos aquáticos. Os valores doíndice de sobreposição de nicho variaram entre 0,38 na seca (moderado e 0,94 na cheia (acentuado. A variação da composição das dietas foi atribuída às oscilações na disponibilidade dos recursos alimentares no ambiente.Feeding habits and trophic overlap of freshwater stingrays Potamotrygon falkneri e Potamotrygon motoro were evaluated in the upper Paraná river floodplain. Samples were collected during periods of drought (August/2004 and flood (January/2005 near Mutum island. Fishhook, harpoon and long line were used to capture the individuals and a total of 49 stomach contents of P. falkneri and 16 of P. motorowere analyzed. Diet composition was analyzed by the relative occurrence and volumetric frequencies. The trophic overlap was quantified by the index of niche overlap of Pianka. Results indicated that both species predominantly consumed mollusks during the floodseason, while in the drought season the diet of P. falkneri was composed mainly by fish and P. motoro for aquatic insects. The values of the index of niche overlap varied from 0.38, in drought (moderate, to 0.94 in flood (accentuated. The seasonal variation of the composition of the diets was attributed to fluctuations in the availability of food resources in the floodplain.

  20. From coexistence to competitive exclusion: can overfishing change the outcome of competition in skates (Chondrichthyes, Rajidae? De la coexistencia a la exclusión competitiva: ¿Puede la sobrepesca cambiar el resultado de la competencia en rayas (Chondrichthyes, Rajidae?

    Directory of Open Access Journals (Sweden)

    Natalia L Ruocco

    2012-03-01

    Full Text Available Competition for food could be a major force driving changes in the community structure of skates (Rajidae subjected to fishing exploitation. Under this hypothesis, small skates are released from competition with larger skates after fishing has depleted the larger species. Here, we compare the abundance patterns of two sympatric skates with similar niches but different life histories, Bathyraja albomaculata (larger and slow-reproducing and Bathyraja macloviana (smaller and faster-reproducing, before (1971, 1978 and after (1998-2004 a 108% increase in industrial bottom trawling on the southeastern South American shelf in order to test the prediction that B. macloviana should competitively exclude B. albomaculata after the increase in fishing mortality. In 1971 and 1978, there was no relationship between the abundance of both species, indicating that they coexisted over large scales. In 1998-2004, the relationship between the abundances of these skates was bell-shaped, indicating that both species increased in abundance at low densities until peaking, after which B. albomaculata decreased when B. macloviana became more abundant, consistent with resource competition. We tested whether food may be a potential limiting resource by comparing the diet of both species. The two species consumed mostly polychaetes, differing only in the consumption of polychaetes from the family Nephthyidae, which was much higher for B. macloviana. Bathyraja macloviana could replace B. albomaculata at high densities when food resources may become scarce. These results support the hypothesis that competition release is an important factor explaining the changes in skate communities in overexploited areas.La competencia por el alimento podría ser una fuerza importante detrás de los cambios en la estructura de las comunidades de rayas (Rajidae bajo explotación pesquera. Según esta hipótesis, las rayas pequeñas son liberadas de la competencia por las rayas de mayor tamaño, al disminuir la abundancia de éstas últimas por la pesca. En este trabajo, se comparan los patrones de abundancia de dos rayas simpátricas con nichos similares pero con diferentes historias de vida, Bathyraja albomaculata (mayor y de reproducción lenta y Bathyraja macloviana (más pequeña y de reproducción más rápida, antes (1971, 1978 y después (1998-2004 de un incremento del 108% en el arrastre de fondo industrial en la plataforma sudeste de América del Sur, para evaluar la predicción que B. macloviana excluiría competitivamente a B. albomaculata después del aumento en la mortalidad por pesca. En 1971 y 1978, no hubo relación entre las abundancias de ambas especies, indicando que, a escalas grandes, coexistían. En 1998-2004, la relación entre las abundancias de ambas especies tuvo forma de campana, indicando que ambas incrementaron su abundancia a densidades bajas hasta alcanzar un máximo, a partir del cual la abundancia de B. albomaculata disminuyó a medida que aumentaba la de B. macloviana, patrón consistente con la competencia por uso de recursos. Se evaluó si el alimento puede ser un recurso limitante mediante la comparación de la dieta de ambas especies. Ambas especies consumieron predominantemente poliquetos y difirieron sólo en el consumo de poliquetos Nephthyidae, mucho mayor en B. macloviana. B. macloviana remplazaría a B. albomaculata a altas densidades, cuando el alimento podría ser escaso. Estos resultados apoyan la hipótesis de que la liberación de la competencia es un factor importante en los cambios en las comunidades de rayas sobreexplotadas.

  1. Characterization of the functional and anatomical differences in the atrial and ventricular myocardium from three species of elasmobranch fishes

    DEFF Research Database (Denmark)

    Larsen, Julie; Bushnell, Peter; Steffensen, John Fleng

    2017-01-01

    We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca(2+) release from the sarcoplasmic reticulum (SR) with ryanodine...

  2. Multiple paternity and hybridization in two smooth-hound sharks.

    Science.gov (United States)

    Marino, Ilaria A M; Riginella, Emilio; Gristina, Michele; Rasotto, Maria B; Zane, Lorenzo; Mazzoldi, Carlotta

    2015-08-10

    Multiple paternity appears to be a common trait of elasmobranch mating systems, with its occurrence likely driven by convenience, due to females seeking to minimize the stress of male harassment. Here we use molecular markers to analyse the frequency of multiple paternity in two related viviparous sharks, Mustelus mustelus and Mustelus punctulatus. We first applied molecular methods to assign pregnant females, embryos and additional reference adults (N = 792) to one of the two species. Paternity analysis was performed using a total of 9 polymorphic microsatellites on 19 females and 204 embryos of M. mustelus, and on 13 females and 303 embryos of M. punctulatus. Multiple paternity occurs in both species, with 47% of M. mustelus and 54% of M. punctulatus litters sired by at least two fathers. Female fecundity is not influenced by multiple mating and in 56% of polyandrous litters paternity is skewed, with one male siring most of the pups. Genetic analyses also revealed hybridization between the two species, with a M. punctulatus female bearing pups sired by a M. mustelus male. The frequency of polyandrous litters in these species is consistent with aspects of their reproductive biology, such as synchronous ovulation and possible occurrence of breeding aggregations.

  3. Exposure to 3,3’,4,4’,5-pentachlorobiphenyl (PCB 126) impacts multiple organ systems in developing little skate (Leucoraja erinacea).

    Science.gov (United States)

    Effects of exposure to coplanar polychlorinated biphenyls (PCBs) and other dioxin-like chemicals on developing vertebrates involve many organ systems, including the skeletal and cardiovascular systems. Apex predators, including those from the class Chondrichthyes (sharks, skates,...

  4. Lõputa meediakunst Berliinis / Piibe Piirma

    Index Scriptorium Estoniae

    Piirma, Piibe

    2007-01-01

    Meediakunsti festival "Transmediale" alapealkirjaga "Unfinished" Berliini kunstiakadeemias ja linnaruumis 31. I-4. II. Konverentsidest, võidutöödest (Herman Asselberghsi "Proof of Life", Antoine Schmitti "Still Living", Tim Shore'i "Cabinet"), Stelarci etendusest "Fractal Flesh", David Rokeby, Herwig Turki ja Günter Stögeri töödest

  5. "Vargamäe kuningriik". "Oscar ja Roosamamma. Kirjad Jumalale" / Tauno Teder

    Index Scriptorium Estoniae

    Teder, Tauno

    2007-01-01

    Autor soovitab vaadata Endla ja Rakvere Teatri suvelavastust "Vargamäe kuningriik" A. H. Tammsaare "Tõe ja õiguse" I ja V osa ainetel, lavastajaks Jaanus Rohumaa ning E.-E. Schmitti loo järgi sündinud näidendit "Oscar ja Roosamamma. Kirjad Jumalale". Lavastaja ja peaosas Üllar Saaremäe, Rakvere Teater

  6. k.a.s.k. project esitab

    Index Scriptorium Estoniae

    2005-01-01

    28. ja 29. VI toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "amor vincit omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös

  7. Teet Kask näitab oma uut, Londonis loodud tantsulavastust / M.T.

    Index Scriptorium Estoniae

    M.T.

    2005-01-01

    28. ja 29. VI toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "Amor Vincit Omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös

  8. Teet Kask toob magistritöö Endla lavale / Kadi Lehtmets

    Index Scriptorium Estoniae

    Lehtmets, Kadi

    2005-01-01

    28. ja 29. juunil toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "Amor Vincit Omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös

  9. "Vargamäe kuningriik". "Oscar ja Roosamamma. Kirjad Jumalale" / Tauno Teder

    Index Scriptorium Estoniae

    Teder, Tauno

    2007-01-01

    Autor soovitab vaadata Endla ja Rakvere Teatri suvelavastust "Vargamäe kuningriik" A. H. Tammsaare "Tõe ja õiguse" I ja V osa ainetel, lavastajaks Jaanus Rohumaa ning E.-E. Schmitti loo järgi sündinud näidendit "Oscar ja Roosamamma. Kirjad Jumalale". Lavastaja ja peaosas Üllar Saaremäe, Rakvere Teater

  10. Biología de los camarones Peneidos del manglar de Guadalupe

    NARCIS (Netherlands)

    Rojas-Beltrán, Ricardo

    1981-01-01

    Durante el desarrollo de dos campañas preliminares en 1976 hemos podido recolectar ocho especies de Peneidos en el manglar de Guadalupe. Las citaremos en orden de importancia: Penaeus (Melicerlus) aztecus subtilis, P. (M.) brasiliensis, P. (M.) duorarum notialis, P. (Litopenaeus) schmitti,

  11. Esietendused

    Index Scriptorium Estoniae

    2001-01-01

    Hendrik Toompere jun. lavastatud Boguslaw Schaefferi "SiinSeal" Eesti Draamateatri väikeses saalis. Nukuteatri ovaalsaalis Ferdinand Veike kava "Ferdinand Veike ja Lilleprintsess". Rakvere Teatris prantsuse näitekirjaniku Eric-Emmanuel Schmitti "Kahe maailma hotell". Vanalinnastuudios Trevor Griffithsi komöödia "Koomikud"

  12. Lõputa meediakunst Berliinis / Piibe Piirma

    Index Scriptorium Estoniae

    Piirma, Piibe

    2007-01-01

    Meediakunsti festival "Transmediale" alapealkirjaga "Unfinished" Berliini kunstiakadeemias ja linnaruumis 31. I-4. II. Konverentsidest, võidutöödest (Herman Asselberghsi "Proof of Life", Antoine Schmitti "Still Living", Tim Shore'i "Cabinet"), Stelarci etendusest "Fractal Flesh", David Rokeby, Herwig Turki ja Günter Stögeri töödest

  13. Biología de los camarones Peneidos del manglar de Guadalupe

    NARCIS (Netherlands)

    Rojas-Beltrán, Ricardo

    1981-01-01

    Durante el desarrollo de dos campañas preliminares en 1976 hemos podido recolectar ocho especies de Peneidos en el manglar de Guadalupe. Las citaremos en orden de importancia: Penaeus (Melicerlus) aztecus subtilis, P. (M.) brasiliensis, P. (M.) duorarum notialis, P. (Litopenaeus) schmitti, Trachypen

  14. Teet Kask toob magistritöö Endla lavale / Kadi Lehtmets

    Index Scriptorium Estoniae

    Lehtmets, Kadi

    2005-01-01

    28. ja 29. juunil toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "Amor Vincit Omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös

  15. k.a.s.k. project esitab

    Index Scriptorium Estoniae

    2005-01-01

    28. ja 29. VI toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "amor vincit omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös

  16. Teet Kask näitab oma uut, Londonis loodud tantsulavastust / M.T.

    Index Scriptorium Estoniae

    M.T.

    2005-01-01

    28. ja 29. VI toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "Amor Vincit Omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös

  17. Ahmeti asemel astub lavale Üllar Saaremäe

    Index Scriptorium Estoniae

    2006-01-01

    10. nov. Rakvere Teatris Dajan Ahmetiga peaosas esietenduma pidanud E.-E. Schmitti näidendis "Oscar ja Roosamamma. Kirjad Jumalale" asub Ahmeti asemel Oscarit mängima tüki lavastaja Üllar Saaremäe

  18. Systematic revision of the Potamotrygon motoro (Müller & Henle, 1841 species complex in the Paraná-Paraguay basin, with description of two new ocellated species (Chondrichthyes: Myliobatiformes: Potamotrygonidae

    Directory of Open Access Journals (Sweden)

    Thiago Silva Loboda

    Full Text Available A systematic revision of the Potamotrygon motoro (Müller & Henle, 1841 species complex in the Paraná-Paraguay basin based on morphological characters was undertaken. Morphological systems analyzed include external morphology, coloration, dermal denticles, and spines, canals of the ventral lateral-line system, and skeletal components. Potamotrygon motoro is widely distributed in the Paraná-Paraguay basin and some of its diagnostic characters are: ocelli present on dorsal disc tricolored, well-defined and evenly distributed, with diameter similar or greater than eye-length; ventral coloration with relatively large whitish central region, with gray or brown area predominant on outer ventral disc margins; dermal denticles well-developed and star-shaped over central disc; labial grooves absent; monognathic heterodonty present in upper and lower jaws of adults. Potamotrygon pauckei Castex, 1963 and Potamotrygon labradori Castex, Maciel & Achenbach, 1963, are synonymized with P. motoro; Potamotrygon alba Castex, 1963, is a nomen dubium in accordance with previous authors. Additionally, two new ocellated species of Potamotrygon from the Paraná-Paraguay basin are described: Potamotrygon pantanensis, sp. nov. and Potamotrygon amandae, sp. nov. These are described and compared with P. motoro and other congeners. Potamotrygon pantanensis, sp. nov. is described from the northern Pantanal region; Potamotrygon amandae, sp. nov. is widespread in the Paraná-Paraguay basin.

  19. 南海主要珊瑚礁水域软骨鱼类的组成与分布%Composition and Distribution of Chondrichthyes in the Main Coral Reef Waters of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    舒黎明; 李永振; 陈国宝

    2006-01-01

    利用1998年3~5月和1999年5~6月在西沙和南沙的12座珊瑚礁水域渔业资源专业调查资料以及1998年2月~1999年12月在南沙群岛水域进行的渔业资源监测调查资料,分析讨论了南海珊瑚礁水域软骨鱼类的组成与分布.专业调查结果:捕获软骨鱼类14属16种,渔获量计64尾2 844.1kg,优势种为大眼角鲨、鼬鲨、日本燕(鱼,工)、侧条真鲨、灰六鳃鲨;监测调查表明南沙珊瑚礁水域的软骨鱼类在全年均可捕获,产量的变动主要与捕捞努力量相关.综合2种调查知:软骨鱼类在南海珊瑚礁水域总体分布范围较广,单鱼种在各个岛礁表现出一定的地域分布性;南海珊瑚礁区捕获软骨鱼类的主要作业方式为延绳钓和大型流刺网.

  20. Species composition and resources density of Chondrichthyes in the continental shelf of northern South China Sea%南海北部海区软骨鱼类种类组成和资源密度分布

    Institute of Scientific and Technical Information of China (English)

    黄梓荣; 陈作志; 曾晓光

    2009-01-01

    根据2006~2007年南海北部海区4季的调查资料,分析该海区软骨鱼类的种类组成和资源密度的分布.结果表明,软骨鱼类有32种,分隶于9目17科,优势种为斑鳐、曾氏兔银鲛、褐黄扁魟、橙黄鲨;渔获率D断面最高(10.19kg/h),B断面最低(4.52kg/h);渔获率有明显的季节变动,夏季最高(12.16kg/h),秋季最低(3.71kg/h),平均渔获率为7.05kg/h;密集分布于180m和140m水深处;其年均资源密度为94.00kg/km2.文中并讨论合理利用和保护该类群的措施.

  1. 软骨鱼系动物与爬行纲动物血红蛋白A2现象的研究%HbA2 Phenomenon in Some Species of Chondrichthyes and Reptilia

    Institute of Scientific and Technical Information of China (English)

    焦勇钢; 秦文斌; 雎天林

    2005-01-01

    目的:比较研究软骨鱼系动物(孔鳐)与爬行纲动物(乌龟、中华鳖、翠青蛇)的"HbA2(血红蛋白A2)现象" . 方法:将动物溶血液和其红细胞悬浮液并排进行淀粉-琼脂糖混合凝胶电泳,观察有无差异.结果:软骨鱼类动物孔鳐"HbA2现象"阳性;爬行纲动物乌龟"HbA2现象"阳性,中华鳖和翠青蛇"HbA2现象"阴性.结论: 在生物进化中,两类动物血红蛋白结构的不同造成了"HbA2现象"的不同.

  2. 石炭纪Listracanthus和Petrodus(软骨鱼类)在中国的发现%Notes on the discovery of Listracanthus and Petrodus (Chondrichthyes) from Upper Carboniferous of Ningxia, China

    Institute of Scientific and Technical Information of China (English)

    卢立伍; 张志军; 方晓思

    2005-01-01

    记述了在宁夏中卫晚石炭世地层中发现的软骨鱼类两个器官属Listracanthus和Petrodus.相似的化石曾在欧洲和北美的石炭纪黑色页岩中出现,但在中国是第一次记述.生物地层学分析表明,这2个器官属的共生出现,可以作为判断晚石炭世地层时代的一个依据.

  3. 海南岛南好地区志留纪软骨鱼类化石的发现及地质意义%Discovery of Chondrichthyes and its Geological Significance from the Silurian of the Nanhao Area, Hainan Island

    Institute of Scientific and Technical Information of China (English)

    李志宏; 谢才富; 付太安; 罗郧

    2006-01-01

    本文描述了海南岛南好地区志留纪足赛岭组三段上部首次发现的软骨鱼类化石,认为它的层位介于扬子区志留系同类生物群第1组合(Hunanacanthus-Eosinacanthus)至第2组合(Sinacanthus-Neosinacanthus)之间,并与第2组合带关系密切,其地质时代为志留纪兰多维列世特列奇中期.根据足赛岭组所产软骨鱼类化石及其伴生的腕足类、珊瑚、三叶虫等,认为它们与扬子区及塔里木盆地西北缘同期生物群面貌彼此接近或关系密切.在兰多维列世特列奇中期,可能同属一个生物古地理区.

  4. Claves para el reconocimiento taxonómico dentario en taxa del Superorden Squalomorphi de Chile (Chondrichthyes: Elasmobranchii Taxonomic dental keys for the Chilean taxa of the Superorder Squalomorphi (Chondricthyes: Elasmobranchii

    Directory of Open Access Journals (Sweden)

    Sylvia Sáez

    2010-01-01

    Full Text Available Se presenta una serie de claves para el reconocimiento dentario de diferentes taxa del Superorden Squalomorphi de Chile. Se seleccionaron características dentarias externas que permitan obtener una observación más expedita que conduzcan a un estudio más acabado, de la diagnosis de los diferentes taxa constituyentes de este grupo de peces, haciéndolas extensibles para estudios de piezas dentales fósiles.A series of taxonomic dental keys is presented for the Chilean taxa of the Superorder Squalomorphi. External dental characteristics were selected for easier observation, leading to more thorough studies. This allows diagnoses of the different taxa comprising this group of fishes and, moreover, can be extended to studies of fossil teeth.

  5. Record of the freshwater stingrays Potamotrygon brachyura and P. motoro (Chondrichthyes, Potamotrygonidae in the lower Uruguay river, South America Registro das raias de água doce Potamotrygon brachyura e P. motoro (Potamotrygonidae no baixo rio Uruguai, America do Sul

    Directory of Open Access Journals (Sweden)

    María Cristina Oddone

    2012-06-01

    Full Text Available Freshwater stingrays, or potamotrygonids, are restricted to Neotropical river drainages. These elasmobranchs are well adapted to freshwater environments and the number of described species gradually increases as further research is carried out. Some of the first studies on their systematics and natural history were carried out in the 1960s and 1970s in southern South America. However, there is no new published data on potamotrygonids from Uruguayan waters since then (except for local journal reports from sportive fishermen and specimens deposited in Uruguayan collections. The present study aims to record the recent occurrence of two species of potamotrygonids caught by sport fishermen, with comments on other published historical records for the same area. As many other elasmobranchs, these species have an important, but not always well understood, role in the Uruguayan rivers ecosystems.As raias de água doce ou potamotrigonídeos estão restritas às drenagens dos rios Neotropicais. Estas raias tem se adaptado bem aos ambientes de água doce e o número de espécies descritas aumenta gradualmente conforme as pesquisas na área se intensificam. Alguns dos primeiros estudos sobre a sistemática e a historia natural deste grupo foram realizados nas décadas de 1960 e 1970 na região Sul de América do Sul. Porém, há poucos dados publicados sobre potamotrigonídeos em águas uruguaias desde então (com exceção de registros de pescadores esportivos publicados em jornais locais, e espécimes depositados em coleções uruguaias. O presente estudo, portanto, tem como objetivo registrar a ocorrência de duas espécies de potamotrigonídeos no Uruguai capturados por pescadores esportivos assim como realizar uma compilação de ocorrências anteriores presentes na literatura. Como muitos outros elasmobrânquios, estas espécies possuem um papel importante nos ecossistemas dos rios uruguaios, embora não completamente compreendido.

  6. Description of a new species of skate of the genus Malacoraja Stehmann, 1970: the first species from the southwestern Atlantic Ocean, with notes on generic monophyly and composition (Chondrichthyes: Rajidae

    Directory of Open Access Journals (Sweden)

    Marcelo R. de Carvalho

    Full Text Available The first report of a western South Atlantic soft skate, genus Malacoraja Stehmann, 1970, is described as Malacoraja obscura, new species, from the southeastern Brazilian continental slope off the states of Espírito Santo and Rio de Janeiro, in depths ranging from 808-1105 m. The new species is known from five specimens and is distinguished from congeners by its unique dorsal coloration with small, faded white spots on disc and pelvic fins, by retaining in larger specimens an irregular row of thorns along dorsal midline of tail (extending from tail base to two-thirds of tail length in 680 mm total length female, and by presenting a ventral tail midline devoid of small denticles only at base (naked region not extending posterior to pelvic fin rear margin. Further diagnostic characters in combination include the lack of scapular thorns in larger specimens, elevated number of tooth rows (64/62 tooth rows in subadult male of 505 mm TL, and 76/74 in large female of 680 mm TL and vertebrae (27-28 Vtr, 68-75 Vprd, ventral disc and tail with a uniform dark brown coloration, paired postventral fenestrae on scapulocoracoid, enlarged posterior postventral fenestra, circular foramen magnum and paired internal carotid foramina on braincase floor. Adult males were unavailable for study, but an anatomical description of M. obscura, n. sp., is provided. Comparisons are made with all known material of M. kreffti, literature accounts of M. senta, and with abundant material of South African M. spinacidermis; M. obscura, n. sp., most closely resembles M. spinacidermis from the eastern South Atlantic in squamation, coloration and size. Malacoraja is monophyletic due to its unique squamation and rostral appendices, and apparently comprises two species-groups, one for M. obscura and M. spinacidermis, and the other for M. kreffti and M. senta, but clarification of species-level relationships must await more anatomical information, particularly of the latter two species.

  7. Grupos tróficos de peixes demersais da plataforma continental interna de Ubatuba, Brasil: I. Chondrichthyes Throphic groups of demersal fish community from the continental shelf: Ubatuba, Brazil. I. Chrondrichthyes

    Directory of Open Access Journals (Sweden)

    Lucy Satiko Hashimoto Soares

    1992-01-01

    Full Text Available Com o objetivo de detectar grupos tróficos, foram analisadas amostras de conteúdos estomacais de sete espécies de peixes cartilaginosos. Os exemplares foram coletados no período de Outubro/85 a Julho/87 na plataforma interna de Ubatuba, SP, Brasil (da costa, até a isóbata de 50 m. A importância dos itens alimentares foi analisada através da freqüência numérica (FN e da freqüência de ocorrência (FO. As espécies foram agrupadas em três grupos distintos: Piscívoros: Squalus cubensis; comedores de peixes e crustáceos bentônicos: Raja castelnaui, Raja cyclophora, Raja agassizi; comedores de invertebrados bentônicos: Psammobatis glansdissimilis, Rhinobatos horkelii, Zapteryx brevirostris.Stomach contents of seven cartilaginous fish species were analysed with the aim to detect trophic groups. Sampling was effectuated between October/85 and July/87 off the coast of Ubatuba (São Paulo, Brazil in waters up 50 m depth. The relative importance of different components of the diet was expressed as a percentage frequency of occurrence and percentage number. The seven species were grouped in: fish feeders - Squalus cubensis; benthonic crustacean and fish feeders - Raja castelnaui, Raja cyclophora, Raja agassizi; benthonic invertebrate feeders - Rhinobatos horkelii, Zapteryx brevirostris, Psammobatis glansdissimilis.

  8. Teet Kask näitab Londonis õpitut / Tiit Tuumalu

    Index Scriptorium Estoniae

    Tuumalu, Tiit, 1971-

    2005-01-01

    28. ja 29. VI toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "Amor Vincit Omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös. Juuli teisel nädalal esineb Endla teatri Küünis M. Ladjanszki ja G. Bergeri tantsuteater Ungarist lavastusega "Ainult 3"

  9. Teet Kask näitab Londonis õpitut / Tiit Tuumalu

    Index Scriptorium Estoniae

    Tuumalu, Tiit, 1971-

    2005-01-01

    28. ja 29. VI toimub Endla teatris rahvusvahelise koostööprojekti esiettekanne Eestis. Etendus "Amor Vincit Omnia" on sündinud lavastaja-koreograafi T. Kase, muusikute Augsti-Knüppeli-Schmitti, hääleseadja Kate Pringle'i ja Londoni linnaülikooli-Labani tudengite koostöös. Juuli teisel nädalal esineb Endla teatri Küünis M. Ladjanszki ja G. Bergeri tantsuteater Ungarist lavastusega "Ainult 3"

  10. Hábitos alimentares e sobreposição trófica das raias Potamotrygon falkneri e Potamotrygon motoro (Chondrichthyes, Potamotrygonidae na planície alagável do alto rio Paraná, Brasil - DOI: 10.4025/actascibiolsci.v28i3.208 Feeding habitats and trophic overlap of the freshwater stingrays Potamotrygon falkneri e Potamotrygon motoro (Chondrichthyes, Potamotrygonidae in the upper Paraná river floodplain, Brazil - DOI: 10.4025/actascibiolsci.v28i3.208

    Directory of Open Access Journals (Sweden)

    Edson Fontes de Oliveira

    2007-11-01

    Full Text Available As raias Potamotrygon falkneri e Potamotrygon motoro foram avaliadas em relação à composição de suas dietas e a sobreposição do nicho trófico nos períodos de seca (agosto/2004 e cheia (janeiro/2005 na planície alagável do alto rio Paraná, em três estações de coleta próximas à ilha Mutum. Foram analisados 49 conteúdos estomacais de P. falkneri e 16 de P. motoro, obtidos de espécimes capturados através de pesca com anzol, fisga (arpão e espinhel. Os conteúdos estomacais foram analisados de acordo com os métodos de freqüência volumétrica e de ocorrência. A similaridade da dieta foi quantificada pelo índice de sobreposição de Pianka. As espécies revelaram flexibilidade alimentar, com ambas consumindo predominantemente moluscos na cheia, enquanto na seca a dieta de P. falkneri foi composta principalmente por peixes e a de P. motoro por insetos aquáticos. Os valores do índice de sobreposição de nicho variaram entre 0,38 na seca (moderado e 0,94 na cheia (acentuado. A variação da composição das dietas foi atribuída à s oscilações na disponibilidade dos recursos alimentares no ambiente.Feeding habits and trophic overlap of freshwater stingrays Potamotrygon falkneri e Potamotrygon motoro were evaluated in the upper Paraná river floodplain. Samples were collected during periods of drought (August/2004 and flood (January/2005 near Mutum island. Fishhook, harpoon and long line were used to capture the individuals and a total of 49 stomach contents of P. falkneri and 16 of P. motoro were analyzed. Diet composition was analyzed by the relative occurrence and volumetric frequencies. The trophic overlap was quantified by the index of niche overlap of Pianka. Results indicated that both species predominantly consumed mollusks during the flood season, while in the drought season the diet of P. falkneri was composed mainly by fish and P. motoro for aquatic insects. The values of the index of niche overlap varied from 0.38, in drought (moderate, to 0.94 in flood (accentuated. The seasonal variation of the composition of the diets was attributed to fluctuations in the availability of food resources in the floodplain.

  11. The Study on Chondrichthyes(Raja porosa) Hemoglobin Component Without Self-interaction and Its Significance for Evolution of Species%鱼纲动物孔鳐血红蛋白自身不相互作用的研究及其进化意义

    Institute of Scientific and Technical Information of China (English)

    张永强; 闫秀兰; 秦文斌; 雎天林

    2006-01-01

    目的:研究一种软骨鱼系动物(孔鳐)自身血红蛋白成份的相互作用.方法:淀粉-琼脂糖混合凝胶交叉电泳.结果:孔鳐自身血红蛋白成份不相互作用.结论:本实验完善了研究室所作的"各种脊椎动物血红蛋白自身相互作用的系列研究".同前面所进行的各种脊椎动物血红蛋白分别与人血红蛋白、胎儿血红蛋白相互作用的研究对照比较,进一步验证脊椎动物血红蛋白与各种蛋白分子在电场中的相互作用的分水岭可能位于爬行纲动物,丰富了血红蛋白分子进化理论.

  12. Description of a natural variant specimen of requiem sharks possibly derived from Scoliodon laticaudus (Chondrichthyes: Carcharhinidae) from South China Sea%南海真鲨科鱼类变异标本的描述,可能源自宽尾曲齿鲛(Scoliodon laticaudus)

    Institute of Scientific and Technical Information of China (English)

    梁沛文; 江艳娥

    2010-01-01

    采用聚类分析和主成分分析,将采集于南沙群岛的一个变异标本同来自于3个属的4尾标本进行比较,确定该变异标本的分类地位.在聚类分析中,标本SCSFRIF19900167、SCSFRIF00000629和标本SCSFRIF900228聚在一起.在主成分分析中,吻、眼睛、胸鳍、腹鳍、臀鳍、尾鳍、第二背鳍、体高、体宽和鳃裂等性状的负倚值大于70%.变异标本SCSFRIF900228与标本SCSFRIF19900167和SCSFRIF00000629的差异特征有:标本SCSFRIF900228的鳃长较短,鳃孔更高,左侧第五鳃孔缺失,右侧第五鳃孔仅3 mm.以上特征显示,变异标本SCSFRIF900228有可能来自宽尾曲齿鲛(Soliodon laticaudus).

  13. Feeding ecology of elasmobranch fishes in coastal waters of the Colombian Eastern Tropical Pacific

    OpenAIRE

    Mejía-Falla Paola A; Navia Andrés F; Giraldo Alan

    2007-01-01

    Abstract Background Stomach contents of 131 specimens of five elasmobranch species (Mustelus lunulatus, Dasyatis longa, Rhinobatos leucorhynchus, Raja velezi and Zapteryx xyster) caught in the central fishing zone in the Pacific Ocean of Colombia were counted and weighed to describe feeding habits and dietary overlaps. Results Twenty-one prey items belonging to four major groups (stomatopods, decapods, mollusks and fish) were identified. Decapod crustaceans were the most abundant prey found i...

  14. Presença do vírus da síndrome da mancha branca em crustáceos decápodes silvestres em lagoas costeiras no Sul do Brasil

    Directory of Open Access Journals (Sweden)

    S.W. Costa

    2012-02-01

    Full Text Available A presença do vírus da síndrome da mancha branca (em inglês WSSV nas principais espécies de camarões, siris e caranguejos de cinco lagoas que recebem o efluente de fazendas afetadas pela enfermidade foi detectada por nested PCR, e inclusões virais nos camarões por histologia. Pela nested PCR encontrou-se a presença de WSSV em 13 de 16 (81,2% amostras de camarões da espécie Farfantepenaeus paulensis, em 13 de 14 (92,8% de Litopenaeus schmitti, em uma de duas de Farfantepenaeus brasiliensis (50%, em 13 de 15 (86,6% de siri da espécie Callinectes danae e em 11 de 12 (91,6% de Callinectes sapidus, e não foi detectada no caranguejo Chasmagnathus granulata em 10 amostras. Inclusões características de WSSV foram observadas em três amostras histológicas de 50 (6,0% no epitélio gástrico e cuticular e nas brânquias de dois exemplares de F. paulensis e um de L. schmitti. É o primeiro relato da presença de WSSV em camarões L. schmitti e no siri C. danae silvestres. As principais espécies de camarões e siris dos ambientes de entorno das fazendas foram contaminadas pelo WSSV, constituindo-se em vetores potenciais do vírus.

  15. Loci microsatélites como marcadores genéticos para la mejora del rendimiento en acuicultura de especies marinas

    OpenAIRE

    Borrell Pichs, Yaisel Juan

    2014-01-01

    Esta tesis se propone como objetivo general comprobar la utilidad de la variación microsatélite en el manejo de poblaciones de tres especies con gran interés económico: el salmón atlántico salmo salar l., el rodaballo scophtalmus maximus, y el camarón blanco litopenaeus schmitti. Los resultados obtenidos obtenidos demuestran que los loci microsatélites son útiles para el manejo de reproductores en las estaciones de cultivo a través del establecimiento de pedigríes si se tienen en cuenta: un a...

  16. Species richness and distribution of chondrichthyan fishes in the Arctic Ocean and adjacent seas

    DEFF Research Database (Denmark)

    Lynghammar, A.; Christiansen, J. S.; Mecklenburg, C. W.

    2013-01-01

    The sea ice cover decreases and human activity increases in Arctic waters. Fisheries and bycatch issues, shipping and petroleum exploitation (pollution issues) make it imperative to establish biological baselines for the marine fishes inhabiting the Arctic Ocean and adjacent seas (AOAS). Species...... richness, zoogeographic affiliations and Red List statuses among chondrichthyan fishes (Chondrichthyes) were examined across 16 AOAS regions as a first step towards credible conservation actions. Published literature and museum vouchers were consulted for presence/absence data. Although many regions...

  17. Contribuição ao conhecimento da ictiofauna do Manguezal de Cacha Pregos, Ilha de Itaparica, Baía de Todos os Santos, Bahia Contribution to knowledge of ichthyofauna of Mangrove Cacha Pregos, Itaparica island, Todos os Santos bay, Bahia

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Duarte Lopes

    1998-01-01

    Full Text Available A check-list of fishes collected in a mangrove in Cacha Pregos, south of ltaparic Island, State of Bahia, Brazil (about 13o07'S,38o48'W from 1988-1989 and 1991-1992 is presented. Fifteen orders, 46 families and 85 species (Teleostei except one Chondrichthyes were identified, represented specimens whose adults live in different marine ecossystems.

  18. A Severe Accident Caused by an Ocellate River Stingray (Potamotrygon motoro) in Central Brazil: How Well Do We Really Understand Stingray Venom Chemistry, Envenomation, and Therapeutics?

    OpenAIRE

    Nelson Jorge da Silva; Kalley Ricardo Clementino Ferreira; Raimundo Nonato Leite Pinto; Steven Douglas Aird

    2015-01-01

    Freshwater stingrays cause many serious human injuries, but identification of the offending species is uncommon. The present case involved a large freshwater stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae), in the Araguaia River in Tocantins, Brazil. Appropriate first aid was administered within ~15 min, except that an ice pack was applied. Analgesics provided no pain relief, although hot compresses did. Ciprofloxacin therapy commenced after ~18 h and continued seven days. T...

  19. Suspension and optical properties of the crystalline lens in the eyes of basal vertebrates.

    Science.gov (United States)

    Kröger, Ronald H H; Gustafsson, Ola S E; Tuminaite, Inga

    2014-06-01

    We have investigated the apparatus suspending the crystalline lens in the eyes of basal vertebrates. Data are presented for Holocephali (Chondrichthyes) and the actinopterygians Polypteriformes, Polyodontidae (Acipenseriformes), Lepisosteiformes, Amiiformes, and one teleost species, the banded archerfish (Toxotes jaculatrix). We also studied the optical properties of the lens in Polypteriformes, Lepisosteiformes, and the archerfish. Together with previously published results, our findings show that there are three basic types of lens suspension in vertebrates. These are i) a rotationally symmetric suspension (Petromyzontida, lampreys; Ceratodontiformes, lungfishes; Tetrapoda), ii) a suspension with a dorso-ventral axis of symmetry and a ventral papilla (all Chondrichthyes and Acipenseriformes), and iii) an asymmetric suspension with a ventral muscle and a varying number of ligaments (all Actinopterygii except for Acipenseriformes). Large eyes with presumably high spatial resolution have evolved in all groups. Multifocal lenses creating well-focused color images are also present in all groups studied. Stable and exact positioning of the lens, in many cases in combination with accommodative changes in lens position or shape, is achieved by all three types of lens suspension. It is somewhat surprising that lens suspensions are strikingly similar in Chondrichthyes and Acipenseriformes (Actinopterygii), while the suspension apparatus in Polypteriformes, usually being regarded as an actinopterygian group more basal than Acipenseriformes, are considerably more teleostean-like. This study completes a series of investigations on lens suspensions in nontetrapod vertebrates, covering all major groups except for the rare and highly derived coelacanths.

  20. 北祁连山东段早石炭世棘鱼类、辐鳍鱼类和软骨鱼类--北祁连山东段石炭纪鱼类序列研究之一%EARLY CARBONIFEROUS FISHES (ACANTHODIAN,ACTINOPTERYGIANS AND CHONDRICHTHYES)FROM THE EAST SECTOR OF NORTH QILIAN MOUNTAIN,CHINA--Carboniferous fish sequence from the east sector of north Qilian Mountain(1)

    Institute of Scientific and Technical Information of China (English)

    王念忠; 金帆; 王炜

    2004-01-01

    对甘肃靖远一带和内蒙古自治区黑山地区早石炭世前黑山组、臭牛沟组和靖远组中三亚纲鱼类微体化石进行了形态学和古组织学研究.这些化石涉及7个目或亚目,含4属4种,其中有2新种.文中记述的属均为全球广布的属.建立了3个早石炭世鱼类组合,这是我国早石炭世第一个鱼类组合序列.辐鳍鱼类和软骨鱼类中2个目的化石均为我国早石炭世鱼类的首次记录.

  1. Adaptabilidad ecofisiológica de organismos acuáticos tropicales a cambios de salinidad

    Directory of Open Access Journals (Sweden)

    Kyung S. Chung

    2001-03-01

    Full Text Available Physiological response of tropical organisms to salinity changes was studied for some marine, estuarine and freshwater fishes (Astyanax bimaculatus, Petenia karussii, Cyprinodon dearborni, and Oreochromis mossambicus, marine and freshwater crustaceans (Penaeus brasiliensis, Penaeus schmitti and Macrobrachium carcinus, and marine bivalves (Perna perna, Crassostrea rhizophorae, and Arca zebra collected from Northeast Venezuela. They were acclimated for four weeks at various salinities, and (1 placed at high salinities to determine mean lethal salinity, (2 tested by increasing salinity 5 ‰ per day to define upper lethal salinity tolerance limit, or (3 observed in a saline gradient tank to determine salinity preference. Acclimation level was the most significant factor. This phenomenon is important for tropical aquatic organisms in shallow waters, where they can adapt to high salinity during the dry season and cannot lose their acclimation level at low salinity during abrupt rain. For saline adaptation of tropical organisms, this behavior will contribute to their proliferation and distribution in fluctuating salinity environments.

  2. [Ecophysiological adaptability of tropical water organisms to salinity changes].

    Science.gov (United States)

    Chung, K S

    2001-03-01

    Physiological response of tropical organisms to salinity changes was studied for some marine, estuarine and freshwater fishes (Astyanax bimaculatus, Petenia karussii, Cyprinodon dearborni, and Oreochromis mossambicus), marine and freshwater crustaceans (Penaeus brasiliensis, Penaeus schmitti and Macrobrachium carcinus), and marine bivalves (Perna perna, Crassostrea rhizophorae, and Arca zebra) collected from Northeast Venezuela. They were acclimated for four weeks at various salinities, and (1) placed at high salinities to determine mean lethal salinity, (2) tested by increasing salinity 5@1000 per day to define upper lethal salinity tolerance limit, or (3) observed in a saline gradient tank to determine salinity preference. Acclimation level was the most significant factor. This phenomenon is important for tropical aquatic organisms in shallow waters, where they can adapt to high salinity during the dry season and cannot lose their acclimation level at low salinity during abrupt rain. For saline adaptation of tropical organisms, this behavior will contribute to their proliferation and distribution in fluctuating salinity environments.

  3. Influência da Serra do Mar na distribuição e biologia de Aeglidae (Crustacea, Anomura) na porção leste do Estado do Paraná

    OpenAIRE

    2013-01-01

    Resumo: Um estudo sobre os padrões de distribuição dos eglídeos (Crustacea, Anomura, Aeglidae) com ocorrência no Estado do Paraná e a variação intraespecífica morfológica de Aegla schmitti dentre populações isoladas pelo conjunto de montanhas da Serra do Mar foi realizado. A análise do padrão de distribuição foi realizado principalmente com base em visitas à coleções científicas, porém coletas adicionais foram realizadas, especialmente nas bacias hidrográficas dos rios Iguaçu, Ribeira do Igua...

  4. Bipteria vetusta n. sp. – an old parasite in an old host: tracing the origin of myxosporean parasitism in vertebrates.

    Science.gov (United States)

    Kodádková, Alena; Bartošová-Sojková, Pavla; Holzer, Astrid S; Fiala, Ivan

    2015-03-01

    Myxosporea (Myxozoa), a group of parasitic Cnidaria, use mostly bony fishes (Teleostei) as intermediate hosts; however, they can also parasitize other vertebrates such as cartilaginous fish (Chondrichthyes). Molecular data of myxosporeans from sharks and rays (Elasmobranchii) revealed these parasites to be one of the most basal representatives in the myxosporean phylogenetic tree, suggesting their ancient evolutionary history. A new myxosporean species, Bipteria vetusta n. sp., was found in the gall bladder of rabbit fish, Chimaera monstrosa (Holocephali; Chondrichthyes), and ssrDNA-based phylogeny revealed its basal position within the marine myxosporean lineage. Molecular dating based on ssrDNA analysis suggested the origin of a stem lineage leading to the marine myxosporean lineage at the time of the origin of Chondrichthyes in the Silurian era. The two common lineages of Myxozoa, Myxosporea and Malacosporea, were estimated to have split from their common ancestor in the Cambrian era. Tracing the history of evolution of the "vertebrate host type" character in the context of molecular dating showed that cartilaginous fish represented an ancestral state for all myxosporeans. Teleosts were very likely subsequently parasitized by myxozoans four times, independently. Myxosporean radiation and diversification appear to correlate with intermediate host evolution. The first intermediate hosts of myxosporeans were cartilaginous fish. When bony fish evolved and radiated, myxosporeans switched and adapted to bony fish, and subsequently greatly diversified in this new host niche. We believe that the present study is the first attempt at molecular dating of myxozoan evolution based on an old myxosporean species – a living myxosporean fossil. Copyright © 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  5. Digenea trematodes in fish of the North Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Vesna PARADIŽNIK

    2007-12-01

    Full Text Available The paper gives an overview of trematodes that have been isolated from the north Adriatic Sea , during a 10-year research program. A total of 63 marine fish species of pelagic and benthic of the classes Chondrichthyes and Osteichthyes were analyzed. We found that 21 fish species ted digenean trematodes (33.33% prevalence, and 12 fish species are reported as hosts for the t time. During our research, 63 species of fish (total of 2659 fish were examined and 25.16 % e found invaded by endohelminths, belonging to 22 digeneans species.

  6. Relação dos peixes coletados nos limites da plataforma continental e nas montanhas submarinas Vitória, Trindade e Martin Vaz, durante a campanha oceanográfica MD-55 Brasil List of fishes collected at the continental shelf limits Vitória, Trinidade and Martin Vaz seamounts during the MD-55 Brazil oceanographic campaign

    OpenAIRE

    1995-01-01

    The result of an agreement between Universidade Santa Ursula, Rio de Janeiro and the Museum of Natural History of Paris, was the oceanographic campaign MD-55 Brasil which took place between May 6th and June 2nd of 1987, aboard the R/V "Marion Dufresne" of the Terres Australes et Antartique Françaises (TAAF). Samples were collected between latitudes 23º36'40"S and 18º49'S. Ichthyofauna sampled was relatively low, and comprised of just one family of Chondrichthyes (three species) and 50 familie...

  7. Total mercury in muscle tissue of five shark species from Brazilian offshore waters: effects of feeding habit, sex, and length.

    Science.gov (United States)

    Penedo de Pinho, Alexandra; Davée Guimarães, Jean Remy; Martins, Agnaldo S; Costa, P A S; Olavo, G; Valentin, Jean

    2002-07-01

    This study was carried out to assess mercury levels in fish from Brazilian offshore waters. Generally sharks have relatively high mercury levels which are also affected by diet, age (associated with length), and sex. Total mercury levels were determined in five shark species with different habits (Carcharhinus signatus, Mustelus canis, Mustelus norrisi, Squalus megalops, and Squalus mitsukurii) which were collected during 1997 in southern Brazil's offshore waters. The highest mercury concentrations, all above the limit established by Brazilian legislation (0.5 microg.g(-1)), were detected in piscivorous species (C. signatus, S. megalops, and S. mitsukurii) with averages of 1.77+/-0.56, 1.9+/-0.58, and 2.22+/- 0.72 microg.g(-1), respectively, while species that feed mainly on invertebrates (M. canis and M. norrisi) had averages of 0.41+/-0.35 and 0.36+/-0.28 microg.g(-1). These results indicate that feeding habits influence total mercury level in sharks. Methylmercury (as a percentage of total mercury) determined in S. mitsukurii and M. canis also showed an influence of feeding habit. Positive correlations between mercury concentration and length were statistically significant (Pmercury levels were generally higher in males than in females for all species (with the exception of S. mitsukurii), a statistically significant correlation was observed only for M. canis.

  8. A macroscopical study of the trapezius muscle of sharks, with reference to the topographically related nerves and vein.

    Science.gov (United States)

    Tanaka, S

    1988-01-01

    The truncus intestino-accessorius of the vagus nerve, spino-occipital, circumbranchial and, in part, the pectoral spinal nerves of sharks Mustelus manazo were macroscopically studied. The morphological features of these nerves along their courses in the epibranchial region were virtually entirely elucidated. The trapezius muscle of Mustelus sharks, in contrast with that of human beings, was found to be supplied solely by rami accessorii--subbranches of the truncus intestino-accessorius of the vagus nerve; no evidence indicating the direct contribution of the spinal nerves to the innervation of the trapezius were obtained. It was also found that the cutaneous branches of the spino-occipital, circumbranchial and pectoral spinal nerves were distributed in the skin overlying the trapezius and the lateral wall of the branchial basket. Topographical relation of the rami accessorii and the branchial branches of the vagus nerve of sharks to the vena capitis lateralis revealed a striking similarity to the relation of the accessory nerve and the nervus laryngeus superior to the vena jugularis interna of human beings. The morphological concept of 'accessory fork' (Accessorius-Gabel) proposed by Haller seems to be important in considering the hypoglosso-cervical ansa complex, superficial branches of the cervical plexus and the vago-accessorius complex, which reminds us more clearly of the embryological trace of its branchial origin of the human trapezius.

  9. Electrophysiological measures of temporal resolution, contrast sensitivity and spatial resolving power in sharks.

    Science.gov (United States)

    Ryan, Laura A; Hemmi, Jan M; Collin, Shaun P; Hart, Nathan S

    2017-03-01

    In most animals, vision plays an important role in detecting prey, predators and conspecifics. The effectiveness of vision in assessing cues such as motion and shape is influenced by the ability of the visual system to detect changes in contrast in both space and time. Understanding the role vision plays in shark behaviour has been limited by a lack of knowledge about their temporal resolution, contrast sensitivity and spatial resolution. In this study, an electrophysiological approach was used to compare these measures across five species of sharks: Chiloscyllium punctatum, Heterodontus portusjacksoni, Hemiscyllium ocellatum, Mustelus mustelus and Haploblepharus edwardsii. All shark species were highly sensitive to brightness contrast and were able to detect contrast differences as low as 1.6%. Temporal resolution of flickering stimuli ranged from 28 to 44 Hz. Species that inhabit brighter environments were found to have higher temporal resolution. Spatial resolving power was estimated in C. punctatum, H. portusjacksoni and H. ocellatum and ranged from 0.10 to 0.35 cycles per degree, which is relatively low compared to other vertebrates. These results suggest that sharks have retinal adaptations that enhance contrast sensitivity at the expense of temporal and spatial resolution, which is beneficial for vision in dimly lit and/or low contrast aquatic environments.

  10. Association of GM4 ganglioside with the membrane surrounding lipid droplets in shark liver.

    Science.gov (United States)

    Li, Yu-Teh; Sugiyama, Eiko; Ariga, Toshio; Nakayama, Jun; Hayama, Masayoshi; Hama, Yoichiro; Nakagawa, Hiroki; Tai, Tadashi; Maskos, Karol; Li, Su-Chen; Kasama, Takeshi; Ksama, Takeshi

    2002-07-01

    By TLC, GM4 was found to be the major ganglioside in the liver of six shark species examined: Odontaspis taurus, Negaprion brevirostris, Sphyrna lewini, Mustelus griseus, Mustelus manazo, and Prionace glauca. A detailed analysis of the glycosphingolipids (GSLs) in the liver of O. taurus (sand tiger shark) showed that it contained approximately 110 nmol of lipid-bound sialic acid per gram of wet tissue, of which 80% was GM4. By extracting the liver of O. taurus with chloroform/methanol, followed by chromatographic separation of GSLs using DEAE-Sephadex A-25 and Iatrobeads columns, we have isolated GM4 in pure form with a yield of approximately 5 mg per 100 g of wet tissue. The structures of both the sugar chain and the ceramide moiety of this GM4 were analyzed by chemical analysis, mass spectrometry, and NMR spectroscopy. Similar to GM4 isolated from other sources, 92% of fatty acids in the ceramide of this GM4 were 2-hydroxylated. However, unlike the long-chain bases found in other GSLs, the total long-chain bases in this GM4 were found to contain 43% octadecasphingenine and 50% nonadecasphingenine. Immunohistochemical analysis using a monoclonal antibody against GM4 revealed that the hepatocytes of both M. griseus (spotless smooth hound) and M. manazo (smooth hound) were filled with lipid droplets and GM4 was primarily associated with the membrane structure surrounding lipid droplets.

  11. Statistical comparison of the results from six analytical chemistry laboratories of the mercury content of muscle tissue of two species of sharks.

    Science.gov (United States)

    Walker, T I

    1977-01-01

    Statistical tests were carried out on the results of chemical analysis for total mercury concentrations of replicate samples of muscle tissue of school shark Galeorhinus australis (Macleay) and gummy shark Mustelus antarcticus Guenther from six independent analytical laboratories. These tests showed that one laboratory produced results 9% below the overall average of all results, another 1% below average while the other four were all 5% above average. Moreover, one laboratory had significantly lower scatter of results than the others, and the percentage scatter (standard error expressed as a percentage of the mean) in two of the laboratories tended to diminish as the magnitude of the results increased. Correction for what were concluded to be wild points indicated that the scatter for all laboratories was below 14%.

  12. Statistical comparison of the results from six analytical chemistry laboratories of the mercury content of muscle tissue of two species of sharks

    Energy Technology Data Exchange (ETDEWEB)

    Walker, T.I.

    1977-01-01

    Statistical tests were carried out on the results of chemical analysis for total mercury concentrations of replicate samples of muscle tissue of school shark Galeorhinus australis (Macleay) and gummy shark Mustelus antarcticus Guenther from six independent analytical laboratories. These tests showed that one laboratory produced results 9% below the overall average of all results, another 1% below average while the other four were all 5% above average. Moreover, one laboratory had significantly lower scatter of results than the others, and the percentage scatter (standard error expressed as a percentage of the mean) in two of the laboratories tended to diminish as the magnitude of the results increased. Correction for what were concluded to be wild points indicated that the scatter for all laboratories was below 14%.

  13. Analysis of EPA and DHA in the viscera of marine fish using gas chromatography.

    Science.gov (United States)

    Zhang, De-Yong; Xu, Xiao-Lu; Shen, Xiu-Ying; Mei, Yu; Xu, Hui-Ying

    2016-03-01

    The viscera of 10 kinds of marine fishes were collected for fish oil extraction and detection of DHA and EPA, two most important polyunsaturated fatty acids. The fish oil extraction ratio for the evaluated fishes varied from 0.95% to 10.18% (wt%). Pseudosciaena crocea presented the highest fish oil yield, followed by Mustelus manazo, Hippoglossus and Sciaenopsocellatus. A gas chromatography method was then established for analysis of EPA/DHA. The EPA concentration (in methyl ester form) in the fish oil varied from 1.39 to 10.65(mg/g). Epinephelus awoara presented the highest EPA concentration (pfish oil varied from 0.58 to 37.02 (mg/g). Epinephelus awoara presented the highest DHA concentration (pfish live was observed. The fishes living in middle depth presented highest EPA/DHA concentration.

  14. Exophiala pisciphila. A study of its development.

    Science.gov (United States)

    Gaskins, J E; Cheung, P J

    1986-03-01

    Exophiala pisciphila is a dematiaceous fungus that belongs to a group of fungi known as the 'black yeasts'. It was isolated from the skin lesions of a smooth dogfish, Mustelus canis Mitchill, that had been born in the shark exhibit tank of the New York Aquarium. The different stages of development of this fungus were studied by light microscopy and scanning electron microscopy to illustrate the morphology and surface structures of conidia and mycelium. The list of marine and fresh water fish, which have been infected by Exophiala spp. and Exophiala-like fungi has been up-dated. Potato Dextrose Agar and Malt Agar proved to be the best growth media, while Corn Meal Agar proved to be the best medium for studying the morphological features of the conidia and mycelial development of E. pisciphila, which exhibited polymorphic conidiogenesis.

  15. APORTES A LA BIOLOGÍA DE TIBURONES Y RAYAS DEMERSALES EN LA REGIÓN NORTE DEL CARIBE COLOMBIANO Contribution To Biology Of Demersal Sharks And Rays In The North Region Of Colombian Caribbean

    Directory of Open Access Journals (Sweden)

    FABIÁN MORENO RODRÍGUEZ

    Full Text Available El presente estudio es una contribución al conocimiento biológico de los peces cartilaginosos en la región norte del Caribe colombiano. Los ejemplares examinados se capturaron con una red demersal, se determinó su peso, longitud total y estado de madurez sexual. Adicionalmente se realizó la ubicación espacial de las capturas y la relación con las variables ambientales. Se capturaron un total de 21 individuos, colectando tres especies de rayas, Dasyatis americana, D. guttata y Rhinobatos percellens, dos de tiburones Mustelus minicanis y Rhizoprionodon porosus, la más común fue D. guttata con 56%, las tallas (longitud total fluctuaron entre los 1760 -394 mm en rayas y 595 -585 mm en tiburones. Se obtuvieron más hembras que machos para todas las especies, con predominio de estados inmaduros y en maduración, solo se registró una hembra grávida de M. minicanis con dos embriones.The present study is a contribution to the biological knowledge of cartilaginous fish from the north of Colombian Caribbean. The samples were obtained from a demersal net in the north of Colombian Caribbean, its weight, overall length and sexual maturity stage was determined. Additionally, spatial distribution and its relationships with environmental variables were explored. A total of 21 individuals were captured, three ray species were collected, Dasyatis americana, D. guttata and Rhinobatos percellens, two sharks Mustelus minicanis and Rhizoprionodon porosus, the most common was D. guttata with 56%, the sizes (total length fluctuated between 1760 - 394 mm in rays and 595 -585 mm in sharks. More females were obtained than males in all the species, with predominance of immature and in maturation states, a single pregnant female of M: minicanis with two embryos was registered.

  16. Complete mitochondrial genome of the largest living fish: whale shark Rhincodon typus (Orectolobiformes: Rhincodontidae).

    Science.gov (United States)

    Chen, Xiao; Ai, Weiming; Pan, Lianghao; Shi, Xiaofang

    2016-01-01

    The whale shark Rhincodon typus (Pisces: Chondrichthyes, Orectolobiformes, Rhincodontidae) is the largest living fish on Earth. In this study, we presented its complete mitogenome. It is 16,928 bp in length, contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and one control region with the typical gene order and transcriptional direction in the vertebrates. Overall base composition of the R. typus mitogenome is 33.5% A, 24.3% C, 12.8% G and 29.5% T. Two start codon (GTG and ATG) and two stop codon patterns (TAG and TAA/T) were found in protein-coding genes. The tRNA-Ser2 could not be folded into the typical cloverleaf secondary structure because of the replacement of its dihydrouridine arm by a simple loop. A termination associated sequences (TAS) and three conserved sequence blocks (CSB1-3) were identified in the control region.

  17. SkateBase, an elasmobranch genome project and collection of molecular resources for chondrichthyan fishes [v1; ref status: indexed, http://f1000r.es/445

    Directory of Open Access Journals (Sweden)

    Jennifer Wyffels

    2014-08-01

    Full Text Available Chondrichthyan fishes are a diverse class of gnathostomes that provide a valuable perspective on fundamental characteristics shared by all jawed and limbed vertebrates. Studies of phylogeny, species diversity, population structure, conservation, and physiology are accelerated by genomic, transcriptomic and protein sequence data. These data are widely available for many sarcopterygii (coelacanth, lungfish and tetrapods and actinoptergii (ray-finned fish including teleosts taxa, but limited for chondrichthyan fishes.  In this study, we summarize available data for chondrichthyes and describe resources for one of the largest projects to characterize one of these fish, Leucoraja erinacea, the little skate.  SkateBase (http://skatebase.org serves as the skate genome project portal linking data, research tools, and teaching resources.

  18. Observations on the radiation of lobe-finned fishes, ray-finned fishes, and cartilaginous fishes: phylogeny of the opioid/orphanin gene family and the 2R hypothesis.

    Science.gov (United States)

    Dores, Robert M; Majeed, Qais; Komorowski, Leanne

    2011-01-15

    At the close of the Devonian Period the rapid decline in the diversity of the lobe-finned fishes was countered by the emergence and diversification of the ray-finned fishes and the cartilaginous fishes that now dominate marine and freshwater ecosystems. All of these jawed vertebrates were derived from the ancestral gnathostomes; a chordate lineage that had experienced two genome duplication events during the evolution of the phylum. This review analyzes trends in the phylogeny of the opioid/orphanin gene family (four prohormone/neuropeptide precursor-coding genes) in the major classes of gnathostomes that survived the extinction events at the close of the Devonian Period and focuses on some features of this gene family that appear to set the cartilaginous fishes (class Chondrichthyes) apart from class Sarcopterygii (lobe-finned fishes and tetrapods) and class Actinopterygii (the ray-finned fishes).

  19. Composição ictiofaunística da área de manguezal da Baía de Guaratuba, Paraná, Brasil Fish faunal composition of the mangrove area of the Guaratuba Bay, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Paulo de Tarso da Cunha Chaves

    1998-01-01

    Full Text Available The Guaratuba Bay (25o52'S, 48o39'W is the second largest estuarine system of the State of Parana, Brazil. It extended inside of the continent for about 15 km and is surrounded by mangroves. Water depth can reach up to six meters. The fish faunal composition of this area was evaluated with a bottom trawl and, occasionally, casting and gill nets. One species of Chondrichthyes and 59 of the Actinopterygii (50 genera and 28 families were reported from the Bay. The results were not significantly different from those of the Paranagua Bay, except by the lower number of species. These differences appear related to distinct collection efforts and the extension of surveyed areas. No species can be considered endemic to the region. Tipically freshwater species were not collected.

  20. Complete mitochondrial genome of the pelagic stingray Pteroplatytrygon violacea (Myliobatiformes: Dasyatidae).

    Science.gov (United States)

    Yang, Chao-Pin; Zhi, Ting-Ting; Zhang, Shuai; Yan, Shuai; Yang, Tingbao

    2016-01-01

    The pelagic stingray Pteroplatytrygon violacea is the only pelagic species of the Dasyatidae (Chondrichthyes: Elasmobranchii), which is widely distributed in all tropical, subtropical and temperate oceans. In this study, the complete mitochondrial genome of Pteroplatytrygon violacea was determined. It is 17,665 bp in length and contains 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 1 control region, with the typical gene order and direction of transcription of vertebrates. The overall nucleotide compositions of the whole mitogenome are 30.8% A, 26.9% C, 28.6% T and 13.7% G. The ND2 and CO1 sequences are highly similar to the corresponding sequences of this species available in NCBI collected from the Atlantic sea.

  1. Complete mitogenome of the pale-edged stingray Dasyatis zugei (Myliobatiformes: Dasyatidae).

    Science.gov (United States)

    Chen, Xiao; Ai, Weiming; Xiang, Dan; Chen, Yunyun; Chen, Shaobo

    2013-06-01

    The complete mitogenome of the pale-edged stingray (Dasyatis zugei) was first confirmed in this study. The mitogenome is 18,264 bp in length and contains 13 protein-coding genes, 2 rRNAs, 22 tRNAs and 1 control region, with the typical gene order in vertebrates. Similar to nucleotide composition of most vertebrate mitogenomes, the nucleotide composition of the pale-edged stingray demonstrates low G and high A+T components. The control region of the pale-edged stingray is 2523 bp in length, the longest known in Chondrichthyes. The termination-associated sequence and two short conserved blocks (CSB II and CSB III) are found in the control region.

  2. Ancient Duplications and Expression Divergence in the Globin Gene Superfamily of Vertebrates: Insights from the Elephant Shark Genome and Transcriptome.

    Science.gov (United States)

    Opazo, Juan C; Lee, Alison P; Hoffmann, Federico G; Toloza-Villalobos, Jessica; Burmester, Thorsten; Venkatesh, Byrappa; Storz, Jay F

    2015-07-01

    Comparative analyses of vertebrate genomes continue to uncover a surprising diversity of genes in the globin gene superfamily, some of which have very restricted phyletic distributions despite their antiquity. Genomic analysis of the globin gene repertoire of cartilaginous fish (Chondrichthyes) should be especially informative about the duplicative origins and ancestral functions of vertebrate globins, as divergence between Chondrichthyes and bony vertebrates represents the most basal split within the jawed vertebrates. Here, we report a comparative genomic analysis of the vertebrate globin gene family that includes the complete globin gene repertoire of the elephant shark (Callorhinchus milii). Using genomic sequence data from representatives of all major vertebrate classes, integrated analyses of conserved synteny and phylogenetic relationships revealed that the last common ancestor of vertebrates possessed a repertoire of at least seven globin genes: single copies of androglobin and neuroglobin, four paralogous copies of globin X, and the single-copy progenitor of the entire set of vertebrate-specific globins. Combined with expression data, the genomic inventory of elephant shark globins yielded four especially surprising findings: 1) there is no trace of the neuroglobin gene (a highly conserved gene that is present in all other jawed vertebrates that have been examined to date), 2) myoglobin is highly expressed in heart, but not in skeletal muscle (reflecting a possible ancestral condition in vertebrates with single-circuit circulatory systems), 3) elephant shark possesses two highly divergent globin X paralogs, one of which is preferentially expressed in gonads, and 4) elephant shark possesses two structurally distinct α-globin paralogs, one of which is preferentially expressed in the brain. Expression profiles of elephant shark globin genes reveal distinct specializations of function relative to orthologs in bony vertebrates and suggest hypotheses about

  3. Basal jawed vertebrate phylogenomics using transcriptomic data from Solexa sequencing.

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    Ming Chen

    Full Text Available The traditionally accepted relationships among basal jawed vertebrates have been challenged by some molecular phylogenetic analyses based on mitochondrial sequences. Those studies split extant gnathostomes into two monophyletic groups: tetrapods and piscine branch, including Chondrichthyes, Actinopterygii and sarcopterygian fishes. Lungfish and bichir are found in a basal position on the piscine branch. Based on transcriptomes of an armored bichir (Polypterus delhezi and an African lungfish (Protopterus sp. we generated, expressed sequences and whole genome sequences available from public databases, we obtained 111 genes to reconstruct the phylogenetic tree of basal jawed vertebrates and estimated their times of divergence. Our phylogenomic study supports the traditional relationship. We found that gnathostomes are divided into Chondrichthyes and the Osteichthyes, both with 100% support values (posterior probabilities and bootstrap values. Chimaeras were found to have a basal position among cartilaginous fishes with a 100% support value. Osteichthyes were divided into Actinopterygii and Sarcopterygii with 100% support value. Lungfish and tetrapods form a monophyletic group with 100% posterior probability. Bichir and two teleost species form a monophyletic group with 100% support value. The previous tree, based on mitochondrial data, was significantly rejected by an approximately unbiased test (AU test, p = 0. The time of divergence between lungfish and tetrapods was estimated to be 391.8 Ma and the divergence of bichir from pufferfish and medaka was estimated to be 330.6 Ma. These estimates closely match the fossil record. In conclusion, our phylogenomic study successfully resolved the relationship of basal jawed vertebrates based on transtriptomes, EST and whole genome sequences.

  4. Trophic strategies in carnivorous fishes: their significance in energy transfer in the deep-sea benthic ecosystem (Meriadzek Terrace — Bay of Biscay)

    Science.gov (United States)

    Mahaut, Marie-Laure; Geistdoerfer, Patrick; Sibuet, Myriam

    Trophic relationships between fish species have been analyzed as a contribution to the construction of an energy transfer model between various groups in the benthic ecosystem of Meriadzek Terrace, located at 170 miles off the west French coast at a depth of 2100m. Attention was given to the carnivorous megafaunal compartment. The importance of the carnivore megafaunal biomass and its part in energy transfer is still unresolved. On the Meriadzek Terrace, numerous Chondrichthyes (sharks and chimeroids) were frequently observed from the manned submersible Cyana or by baited camera; their biomass appears to be exceptionally large. Results of a photographic survey conducted using the unmanned free vehicle Epaulard have given estimates of 22 per 10 4m 2 of teleost fishes (belonging to 8 different families and one suborder) but included no Chondrichthyes (except one specimen of Rajidae). From baited camera observations, however, we conclude that carcasses falling to the bottom on the Terrace are exploited only by selacians as the bait was never seen to be eaten by macrourids, morids or synaphobranchids although they always attended the baits before the arrival of large scavengers. Trophic specialization strategies occur in this deep-sea ecosystem and our further studies on the energy transfer model for the Meriadzek Terrace will differentiate between strategies exploiting two sources of organic input to the bottom environment: organic particles and large carcasses. In one case, carbon transfer is via the whole benthic food web in which each link is specified by size and trophic behaviour. This pathway ends in the carnivorous megafaunal compartment, which includes benthic fishes, consumers of the local epibenthic and sometimes inbenthic, macro- and megafauna. The second pathway originates with carcass falls, and carbon transfer is direct to the benthopelagic scavengers observed frequently at the Meriadzek Terrace.

  5. Development of revolutionizing biomaterials substituting various mammalian organs by means of sintered bioceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, T. [West Saitama National Central Hospital, Tokorozawa (Japan); Hirota, K. [National Inst. for Research in Inorganic Materials Tsukuba, Ibaraki (Japan); Nishihara, K. [Tokyo Univ. (Japan). Dept. of Oral Surgery

    2001-07-01

    Development of biomaterials substituting various mammalian organs can be carried out by means of experimental evolutionary studies using collagen -hydroxyapatite composite, derived from adult cattle. The revolution of the tissue-immune system can be studies by compound-ceramics of collagen-hydroxyapatite composite. Collagen-hydroxyapatite composite was sintered by high-pressure technique using collagen extracted from cattle skin, which had antigenicity. Artificial bone marrow chambers were fabricated with the sintered collagen-hydroxyapatite composite. Experimental evolutionary studies using mammals (dogs) and chondrichthyes (sharks) were carried out implanting the chambers into their muscles. The result showed that around the collagen composed chambers implanted into dorsal muscle of dogs, marked cell differentiation as well as dedifferentiation with atypia could be observed, which resembled a part the digestive tract of intestine histologically. Around the chambers implanted into dorsal muscle of sharks hemopoietic nests could be observed, which were quite similar to those induced by the chambers of conventionally sintered hydroxyapatite. Hemopoiesis and osteoid formation 4 months after surgery were observed around the collagen-apatite chamber implanted in the shark muscle as well as in upper site of vertebral cartilage of the spinal cord. No bone marrow in the cartilaginous tissue in upper site of the spinal cord is evident in control sharks. Xenotransplantation of skin, i.e., skin grafts between sharks of different kinds of species, as well as between sharks and xenopus (amphibian), sharks and mammals (rat) are carried out. All of them are successful and chimera placoids between them are developed. After that, the author successfully carried out xenotransplantation of various organs of chondrichthyes into those of dogs. (orig.)

  6. Cadmium and lead in seafood from the Aratu Bay, Brazil and the human health risk assessment.

    Science.gov (United States)

    Silva da Araújo, Cecilia Freitas; Lopes, Mariângela Vieira; Vaz Ribeiro, Mirian Rocha; Porcino, Thiago Santos; Vaz Ribeiro, Amanda Santos; Rodrigues, Juliana Lima Gomes; do Prado Oliveira, Sérgio Soares; Menezes-Filho, José Antonio

    2016-04-01

    This study aimed to evaluate cadmium (Cd) and lead (Pb) levels in seafood and perform a risk assessment based on individual food consumption frequency of inhabitants of the Aratu Bay, Brazil. From December 2013 to November 2014, ready-to-market seafood, including fish [pititinga (Lile piquitinga) and small green eel (Gobionellus oceanicus)], mollusks [mussel (Mytella guyanensis) and oyster (Crassostrea rhizophorae)], and crustaceans [white shrimp (Litopenaeus schmitti) and blue crab (Callinectes exasperatus)], were purchased bimonthly from a local artisanal shellfish harvester. Metal levels were analyzed by graphite furnace atomic absorption spectrometry (GFAAS). Based on the volunteer’ seafood consumption, estimates of the non-carcinogenic target hazard quotients (THQs) were calculated. The annual concentrations (μg/g, w/w) of Cd were 0.007 (±0.001) in crustaceans, 0.001 (±0.0003) in fish, and 0.446 (±0.034) in mollusks. Lead levels were

  7. New records of caridean shrimps (Decapoda: Caridea from shallow water along the northern Yucatan peninsula coasts of México

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    Luis Daniel Santana-Moreno

    Full Text Available The northern coast of the Mexican state of Yucatán has only been cursorily sampled in the past, with most of this effort concentrated on the largest coral reef in the Gulf of México, Arrecife Alacranes. The present study reports on recent collections (June 2008 - September 2013 of caridean shrimp in Yucatán, including Arrecife Alacranes and other reefs, as well as coastal lagoons and beaches. Additionally, a number of species are reported based on older, unidentified museum material. Six species represent new records for the Gulf of México [Janicea antiguensis (Chace, 1972, Gnathophyllum modestum Hay, 1917, Lysmata jundalini Rhyne, Calado and dos Santos, 2012, Periclimenes sandyi De Grave, 2009, Rapipontonia platalea (Holthuis, 1951a, Typton tortugae, McClendon, 1911], and 11 species are confirmed new records for México [Lysmata ankeri Rhyne and Lin, 2006, L. pederseni Rhyne and Lin, 2006, L. rafa Rhyne and Anker, 2007, Ascidonia miserabilis (Holthuis, 1951b, A. quasipusilla (Chace, 1972, Neopontonides chacei Heard, 1986, Periclimenaeus maxillulidens (Schmitt, 1936, P. pearsei (Schmitt, 1932, P. schmitti Holthuis, 1951b, Typton prionurus Holthuis, 1951b, Processa manningi De Grave and Felder, 2012], adding up to a total of 17 newly reported species for the East coast of México. Further, the colour pattern of several species is documented for the first time.

  8. One new species of Platybothrium from marine fishes in Xiamen, Fujian, China%厦门海域鱼类瘤槽科平槽属绦虫一新种

    Institute of Scientific and Technical Information of China (English)

    王彦海; 杨文川

    2001-01-01

    本文报道厦门海域软骨鱼灰星鲨(Mustelus griseus)感染的四叶目瘤槽科绦虫新种——厦门平槽绦虫Platybothrium xiamenensis sp. nov.,对新种形态特征进行了详细描述并与近似种作了比较.%One new species of Platybothrium from marine fishes in Xiamen, Fujian, China is reported. The type specimens are deposited in Parasitology Research Laboratory, Xiamen University. All measurements are given in millimetre unless otherwise stated.Platybothrium xiamenensis sp.nov. (PlateⅠ)   Host:Mustelus griseusLocation: Spiral intestine;   Locality: Xiamen, Fujian, China   Length 82~126. Strobila slender, composed of 70~116 proglottids. Bothridia elliptical, 0.289~0.371 (0.314±0.033) long by 0.158~0.177 (0.170±0.067) wide, each bearing at its posterior end a cup-like loculus and with one pair of hooks. All hooks forked, one hook of each pair three-pronged, the other two-pronged. Each proglottis is marked off by leaf-like projections in dorsal and ventral pairs of the posterior border. Mature proglottids longer than wide, 1.705~2.590 (2.066±0.280) long by 1.545~2.050 (1.864±0.214) wide. Genital pores in posterior 35.1~40.9% of proglottids, irregularly alternating. Testes oval, numerous, closely massed in medulla between ovarial isthmus and anterior end of proglittis. Cirrus pouch 0.509~0.637 (0.576±0.048) long by 0.284~0.332 (0.312±0.016) wide, containing spined eversible cirrus. Ovary consisting of two coarsely lobed wings. Vagina anterior to cirrus pouch, vaginal sphincter distinct. Vitellaria finely follicular, extending throughout length of proglottis just outside of excretory stems. Uterus median, developing saccular outgrowths on each side.

  9. Decomposition of trimethylamine oxide related to the use of sulfites in shrimp Decomposição do óxido de trimetilamina relacionada ao uso de sulfitos em camarão

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    Israel H.A. CINTRA

    1999-12-01

    Full Text Available Currently, sulfites are employed on board to inhibit melanosis (blackspot on crustaceans. However, when used in excess this chemical compound not only can cause adverse reactions in SO2-sensitive individuals, but also favors the decomposition of trimethylamine oxide (TMAO into dimethylamine (DMA and formaldehyde (FA, thus compromising the quality of the product, which can be observed mainly through the texture change of the meat after cooking. This study was conducted to verify the increase of the contents of DMA and FA by the excessive use of sodium metabisulfite in white shrimp (Penaeus schmitti. For laboratory trials, shrimp were beheaded, washed and immersed in a 2% sodium metabisulfite solution for 10 minutes. Specimens were stored either on ice and maintained for 48 hours in refrigeration, or stored in a freezer for 48 hours. Samples were collected at intervals of 0, 24 and 48 hours, and analyzed for residual SO2, TMAO, TMA, DMA and FA. The immersion of shrimp in a 2% sodium metabisulfite for 10 minutes favored the decomposition of TMAO which greatly increased the contents of DMA and FA. The FA and DMA measured in fresh shrimp was low. Moreover, the storage of shrimp tails on ice resulted in a significant reduction of the TMA, DMA, FA and residual SO2 contents compared to the specimens under frozen storage.O uso de sulfitos é uma prática utilizada a bordo para prevenir a melanose (manchas pretas em crustáceos. No entanto, este composto, além de causar reações alérgicas em pessoas sensíveis ao SO2 quando usado em excesso, proporciona a decomposição do óxido de trimetilamina (OTMA em dimetilamina (DMA e formaldeído (FA, comprometendo assim a qualidade do pescado, principalmente no que se refere ao endurecimento da carne após cozimento. O presente trabalho foi desenvolvido com a finalidade de se verificar o aumento dos níveis de DMA e FA pelo uso em excesso de metabissulfito de sódio em camarão branco, Penaeus schmitti . Em

  10. Monitoring of carcinofauna abundance and diversity during eight years of expressway construction in Santa Catarina, Brazil Ocho años de monitoreo de la abundancia y diversidad de la fauna carcinológica durante la construcción de una carretera en Santa Catarina, Brasil

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    Felipe Freitas Junior

    2010-01-01

    Full Text Available Crustaceans are important in estuarine ecosystems, transferring energy to higher trophic levels and contributing to artisanal and industrial fisheries. This paper aims to evaluate the carcinofauna diversity and abundance in Saco dos Limões and how this changed when affected by dredging during the construction of an expressway through South Bay, Florianópolis, Santa Catarina, Brazil. Collections were made onboard a commercial fishing boat for three months, day and night, at six sampling sites from 1997 to 2006. The families Penaeidae and Portunidae were the most diverse in terms of taxa, with the largest species abundances. The dominant species were the shrimps Farfantepenaeus brasiliensis, F. paulensis, and Litopenaeus schmitti, and the crab Callinectes danae. The largest abundances were found in two areas, in the summer and at night. The diversity and equitability Índices showed similar patterns, with the highest values in autumn and winter. Acording to the Jaccard Index, the similarity of the crustacean composition was highest for the years 2005 and 2006 and lowest between 1997 and 2005. The structure of the carcinofauna changed over the years, with high mortalities during dredging operations followed by a recovery in the subsequent years. Our observations indicated that dredging did not have catastrophiçõeffects ñor did it produce long-term disturbances in the carcinofauna of the estuary. It is important to monitor natural resources in order to record the extent and limits of human impacts on the environment.Los crustáceos son importantes en el ecosistema estuarino, transfiriendo energía hacia los niveles tróficos más altos y contribuyendo a la pesca artesanal e industrial. El objetivo del artículo es evaluar la diversidad y abundancia de la fauna carcinológica de la región de Saco dos Limões y sus cambios bajo la influencia de las actividades de dragado durante la construcción de la carretera Bahía sur, Florianópolis, Santa

  11. Evolutionary and functional relationships of B cells from fish and mammals: insights into their novel roles in phagocytosis and presentation of particulate antigen.

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    Sunyer, J Oriol

    2012-06-01

    The evolutionary origins of Ig-producing B cells appear to be linked to the emergence of fish in this planet. There are three major classes of living fish species, which from most primitive to modern they are referred to as agnathan (e.g., lampreys), Chondrichthyes (e.g., sharks), and teleost fish (e.g., rainbow trout). Agnathans do not have immunoglobulin- producing B cells, however these fish contain a subset of lymphocytes-like cells producing type B variable lymphocyte receptors (VLRBs) that appear to act as functional analogs of immunoglobulins. Chondrichthyes fish represent the most primitive living species containing bona-fide immunoglobulin-producing B cells. Their B cells are known to secrete three types of antibodies, IgM, IgW and IgNAR. Teleost fish are also called bony fish since they represent the most ancient living species containing true bones. Teleost B cells produce three different immunoglobulin isotypes, IgM, IgD and the recently described IgT. While teleost IgM is the principal player in systemic immunity, IgT appears to be a teleost immunoglobulin class specialized in mucosal immune responses. Thus far, three major B cell lineages have been described in teleost, those expressing either IgT or IgD, and the most common lineage which co-expresses IgD and IgM. A few years ago, the study of teleost fish B cells revealed for the first time in vertebrates the existence of B cell subsets with phagocytic and intracellular bactericidal capacities. This finding represented a paradigm shift as professional phagocytosis was believed to be exclusively performed by some cells of the myeloid lineage (i.e., macrophages, monocytes, neutrophils). This phagocytic capacity was also found in amphibians and reptiles, suggesting that this innate capacity was evolutionarily conserved in certain B cell subsets of vertebrates. Recently, the existence of subsets of B cells with phagocytic and bactericidal abilities have also been confirmed in mammals. Moreover, it has

  12. Mercury content in shark species from the South-Eastern Brazilian coast.

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    Lacerda, L D; Paraquetti, H H; Marins, R V; Rezende, C E; Zalmon, I R; Gomes, M P; Farias, V

    2000-11-01

    We present here the first results of Hg concentrations in three small shark species (Rhizoprionodon lalandei, R. porosus and Mustelus higmani) from the SE Brazilian coast. Mercury concentrations in R. lalandei ranged from 21.5 to 280.0 ng.g-1 dry weight (d.w.) (average 74.6 ng.g-1 d.w.; 17.9 ng.g-1 wet weight). In R. porosus, concentrations ranged from 7.6 to 90.5 ng.g-1 d.w. (average 42.2 ng.g-1 d.w., 9.4 ng.g-1 wet weight), whereas in M. higmani, concentrations ranged from 13.0 to 162.8 ng.g-1 d.w. (average 54.9 ng.g-1 d.w., 13.4 ng.g-1 wet weight). These concentration ranges are very low compared with values reported for other large shark species of the Southwestern Atlantic Ocean. There was a significant positive correlation between Hg concentrations and individual size, suggesting that biomagnification is occurring in these animals.

  13. Feeding ecology of elasmobranch fishes in coastal waters of the Colombian Eastern Tropical Pacific.

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    Navia, Andrés F; Mejía-Falla, Paola A; Giraldo, Alan

    2007-09-18

    Stomach contents of 131 specimens of five elasmobranch species (Mustelus lunulatus, Dasyatis longa, Rhinobatos leucorhynchus, Raja velezi and Zapteryx xyster) caught in the central fishing zone in the Pacific Ocean of Colombia were counted and weighed to describe feeding habits and dietary overlaps. Twenty-one prey items belonging to four major groups (stomatopods, decapods, mollusks and fish) were identified. Decapod crustaceans were the most abundant prey found in stomachs. The mantis shrimp Squilla panamensis was the main prey item in the diet of M. lunulatus; tiger shrimp Trachypenaeus sp. was the main prey item in the diet of Rhinobatos leucorhynchus and Raja velezi, and Penaeidae shrimp were the main prey items in the diet of Z. xyster. Furthermore, fish were important in the diet of Raja velezi, Z. xyster and D. longa. The greatest diet breadth corresponded to Z. xyster whereas M. lunulatus was the most specialized predator. Finally, four significant diet overlaps between the five species were found, attributable mainly to Squillidae, Penaeidae and Fish. Shrimps (Penaeidae and stomatopods) and benthic fishes were the most important food types in the diet of the elasmobranch species studied. Diet breadth and overlap were relatively low. Determination of food resource partitioning among the batoid species studied was not possible. However, we identified partitions in other niche axes (time of feeding activity and habitat utilization). It is possible to assume that diffuse competition could be exceeding the biunivocal competition among the studied species. Therefore, this assemblage would have a strong tendency to trophic guild formation.

  14. Comparative study of enzymatic antioxidants in muscle of elasmobranch and teleost fishes.

    Science.gov (United States)

    Vélez-Alavez, Marcela; De Anda-Montañez, Juan A; Galván-Magaña, Felipe; Zenteno-Savín, Tania

    2015-09-01

    Exercise may cause an imbalance between pro-oxidants and antioxidants. In skeletal muscle, oxygen flow can increase considerably during vigorous exercise. The antioxidant system in athletes contributes to neutralize the concomitant rise in reactive oxygen species (ROS) production. The objective of this study was to compare the antioxidant system in muscle of three species of elasmobranchs and teleosts, considering differences in swimming capacity among species within each group and evolutionary differences between the two groups. Muscle samples were collected from elasmobranchs (Isurus oxyrinchus, Prionace glauca, Mustelus henlei) and teleosts (Totoaba macdonaldi, Kajikia audax and Coryphaena hippurus) in the coast of the Baja California peninsula, Mexico. The enzymatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) was determined by spectrophotometry. The activity of the antioxidant enzymes CAT, GPx and GST was higher in elasmobranchs, as a group, than in teleosts. In fish species with high swimming capacities, P. glauca, K. audax and C. hippurus, antioxidant enzyme activity was higher in comparison with species with lower swimming capacities, M. henlei and T. macdonaldi. It is possible that antioxidant enzymes, particularly SOD, GPx and GST, contribute to avoidance of oxidative damage in teleost and elasmobranch species with higher swimming capacities. The antioxidant enzyme activities in fish appear to depend mainly on their swimming capacity and life style rather than the evolutionary group (elasmobranchs, teleosts).

  15. Odor tracking in sharks is reduced under future ocean acidification conditions.

    Science.gov (United States)

    Dixson, Danielle L; Jennings, Ashley R; Atema, Jelle; Munday, Philip L

    2015-04-01

    Recent studies show that ocean acidification impairs sensory functions and alters the behavior of teleost fishes. If sharks and other elasmobranchs are similarly affected, this could have significant consequences for marine ecosystems globally. Here, we show that projected future CO2 levels impair odor tracking behavior of the smooth dogfish (Mustelus canis). Adult M. canis were held for 5 days in a current-day control (405 ± 26 μatm) and mid (741 ± 22 μatm) or high CO2 (1064 ± 17 μatm) treatments consistent with the projections for the year 2100 on a 'business as usual' scenario. Both control and mid CO2 -treated individuals maintained normal odor tracking behavior, whereas high CO2 -treated sharks significantly avoided the odor cues indicative of food. Control sharks spent >60% of their time in the water stream containing the food stimulus, but this value fell below 15% in high CO2 -treated sharks. In addition, sharks treated under mid and high CO2 conditions reduced attack behavior compared to the control individuals. Our findings show that shark feeding could be affected by changes in seawater chemistry projected for the end of this century. Understanding the effects of ocean acidification on critical behaviors, such as prey tracking in large predators, can help determine the potential impacts of future ocean acidification on ecosystem function.

  16. Predictive habitat suitability models to aid conservation of elasmobranch diversity in the central Mediterranean Sea

    Science.gov (United States)

    Lauria, V.; Gristina, M.; Attrill, M. J.; Fiorentino, F.; Garofalo, G.

    2015-08-01

    Commercial fisheries have dramatically impacted elasmobranch populations worldwide. With high capture and bycatch rates, the abundance of many species is rapidly declining and around a quarter of the world’s sharks and rays are threatened with extinction. At a regional scale this negative trend has also been evidenced in the central Mediterranean Sea, where bottom-trawl fisheries have affected the biomass of certain rays (e.g. Raja clavata) and sharks (e.g. Mustelus spp.). Detailed knowledge of elasmobranch habitat requirements is essential for biodiversity conservation and fisheries management, but this is often hampered by a poor understanding of their spatial ecology. Habitat suitability models were used to investigate the habitat preference of nine elasmobranch species and their overall diversity (number of species) in relation to five environmental predictors (i.e. depth, sea surface temperature, surface salinity, slope and rugosity) in the central Mediterranean Sea. Results showed that depth, seafloor morphology and sea surface temperature were the main drivers for elasmobranch habitat suitability. Predictive distribution maps revealed different species-specific patterns of suitable habitat while high assemblage diversity was predicted in deeper offshore waters (400-800 m depth). This study helps to identify priority conservation areas and diversity hot-spots for rare and endangered elasmobranchs in the Mediterranean Sea.

  17. Ontogeny of Feeding Mechanics in Smoothhound Sharks: Morphology and Cartilage Stiffness.

    Science.gov (United States)

    Wilga, Cheryl A D; Diniz, Stephanye E; Steele, Preston R; Sudario-Cook, Jordan; Dumont, Elizabeth R; Ferry, Lara A

    2016-09-01

    The diet of dusky smoothhound sharks, Mustelus canis, shifts over ontogeny from soft foods to a diet dominated by crabs. This may be accompanied by changes in the skeletal system that facilitates the capture and processing of large and bulky prey. The hyoid arch, for example, braces the jaws against the cranium, and generates suction for prey capture and intraoral transport. In this study, ontogenetic changes in the hyoid arch were investigated by quantifying size, mineralization, and stiffness to determine whether increasingly stiffer cartilages are associated with the dietary switch. Total length and length of the hyomandibula and ceratohyal cartilages over ontogeny were the proxy for body size. Cross-sectional area, percent mineralization, and second moment of area were quantified in 28 individuals spanning most of the natural size range. Mechanical compression tests were conducted to compare flexural stiffness to size. Our results show that the morphological characters tested for the hyomandibular and ceratohyal cartilages scales isometrically with length. While stiffness of the hyomandibular and ceratohyal cartilages scales isometrically with length when assessed on morphological characters alone (second moment of area), this relationship becomes allometric when mechanical properties are included (flexural stiffness). Thus, while the hyoid arch elements grow isometrically, the mechanical properties dictate a scaling relationship that dwarfs morphological characteristics. The various combinations of morphologies and ontogenetic trajectories of chondrichthyan species illustrate the tremendous flexibility that they possess in the functional organization of the feeding apparatus.

  18. Myoglobins of cartilaginous fishes III. Amino acid sequence of myoglobin of the shark Galeorhinus australis.

    Science.gov (United States)

    Fisher, W K; Koureas, D D; Thompson, E O

    1981-01-01

    Myoglobin isolated from the red muscle of the school shark Galeorhinus australis was purified by gel filtration and ion-exchange chromatography. The amino acid sequence was determined following digestion with trypsin and purification of the peptides by paper ionophoresis and chromatography. Sequences of purified peptides were determined by the dansyl-Edman procedure and the peptides aligned by homology with the sequence of the myoglobin of the gummy shark Mustelus antarcticus. The two myoglobin sequences showed a marked similarity (16 differences), but both sequences showed approximately the same number of differences (68) from myoglobin of the Port Jackson shark Heterodontus portusjacksoni. There are 19 residues unique to three shark myoglobin sequences. As found with other fish myoglobins there are 148 residues with deletions of four residues at the amino terminal end as well as one residue in the CD region. The amino terminal residue is acetylated. The distal E7 histidine residue was found to be replaced by glutamine, as only previously reported for the myoglobin sequence of gummy shark.

  19. The artisanal elasmobranch fishery of the Pacific coast of Baja California Sur, Mexico, management implications

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    Sergio R. Ramirez-Amaro

    2013-09-01

    Full Text Available Artisanal fisheries in Mexico account for approximately 40% of the total national catch. In 2009, Baja California Sur (BCS had the second largest catch of elasmobranchs on the Mexican Pacific coast. This paper characterizes and describes the artisanal elasmobranch fishery of Pacific coast of BCS from 2000 to 2010. Sixty artisanal camps were documented, of which 45 targeted elasmobranchs, using primarily gillnets and longlines. We identified 52 elasmobranch species. Gillnetting accounted for 73.5% of the fishing effort and most frequently captured Rhinobatos productus, Mustelus henlei and Myliobatis californica. Longline fishing accounted for 26.5% of effort, most frequently capturing Prionace glauca and Isurus oxyrinchus. The prevalence of juveniles of several species (e.g., Cephaloscyllium ventriosum, Galeorhinus galeus, Isurus oxyrinchus, and Myliobatis californica within landings suggests that fishing effort may be opportunistically directed at breeding or nursery areas. Despite the dominance of species with wide distributions, we observed a significant biogeographic pattern in the abundance of some species relative to Bahia Magdalena. Results of the present study will be useful to detect changes in the structure of commercially exploited elasmobranch populations, and to provide useful indications for management purposes.

  20. Morphological features of coronary arteries and lesions in hearts from five species of sharks collected from the northwestern Atlantic Ocean.

    Science.gov (United States)

    Borucinska, J D; Obasa, O A; Haffey, N M; Scott, J P; Williams, L N; Baker, S M; Min, S J; Kaplan, A; Mudimala, R

    2012-10-01

    Morphological features of coronary arteries and incidental lesions are reported from hearts in five species of sharks, the shortfin mako shark, Isurus oxyrhinchus Rafinesque, thresher shark Alopias vulpinus (Bonaterre), blue shark, Prionace glauca L., the smooth dogfish, Mustelus canis (Mitchill), and spiny dogfish, Squalus acanthias L. Sharks were collected from the northwestern Atlantic between June and August from 1996 to 2010. They were necropsied dockside and the hearts were preserved in buffered formalin. Routine sections including ventricle/conus arteriosus and the atrio-ventricular junctions were embedded in paraffin, stained with common histological and immunohistochemical methods and examined by brightfield microscopy. Myointimal hyperplasia, medial myo-myxomatous hyperplasia and bifurcation pads were observed commonly, and medial muscle reorientation and epicardial myeloid tissues were rare. All the above features differed in severity, prevalence and distribution depending on anatomical site and shark species/size. Morphometric analysis indicated that myomyxomatous hyperplasia is associated with luminal narrowing of blood vessels. As suggested previously, the described morphological features are most likely physiological responses to blood flow characteristics. Vascular and cardiac lesions were uncommon and included, granulomatous proliferative epicarditis with fibroepitheliomas, myxomatous epicardial expansions, medial arterial vacuolation, myocardial fibrosis, acute ventricular emboli and parasitic granulomas. The lesions of embolism, proliferative and granulomatous epicarditis and myocardial fibrosis were in all sharks associated with capture events including retained fishing hooks. The significance and aetiopathogenesis of medial vacuolation and epicardial myxomatous expansions remains unclear. © 2012 Blackwell Publishing Ltd.

  1. Shark fisheries in Central America a review and update.

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    José Rodrigo Rojas M.

    2016-03-01

    Full Text Available La demanda por derivados del tiburón, especialmente aletas y cartílago, ha llevado a una expansión de las pesquerías y del comercio a través de la región. El incremento en el esfuerzo pesquero, las escasas referencias biológicas y la falta de manejo, son factores claves que impactan negativamente esta pesquería. Con el fin de contar con información sobre el estado de las poblaciones, zonas de pesca y crianza, aspectos socioeconómicos y medidas necesarias para la conservación, se llevó a cabo esta investigación. Se identificaron 24 especies de importancia comercial, siendo las más importantes: Carcharhinus falciformis y Nasolamia velox (Guatemala, C. falciformis (Nicaragua, C. falciformis y Mustelus dorsalis (Costa Rica, C. obscurus (El Salvador, C. limbatus (Panamá. Los productos comerciales incluyen carne, aleta, aceite, cartílago y piel. Las aletas son el producto de mayor valor (i.e. aletas caudales secas se venden desde $150 a $400/kg en Costa Rica y son exportadas a Hong Kong, Taiwan, Japón y Estados Unidos.

  2. Nocturnal Fish Use of New Jersey Marsh Creek and Adjacent Bay Shoal Habitats

    Science.gov (United States)

    Rountree, R. A.; Able, K. W.

    1997-06-01

    Night-time sampling with gill nets in the Little Egg Harbor estuary revealed a component of the estuarine fish fauna, hitherto poorly documented, which is comprised of relatively large size classes of juvenile and adult life history stages. The fishesMustelus canis, Pomatomus saltatrix, Paralichthys dentatus, Brevoortia tyrannus, Prionotus evolansandAlosa mediocriswere the most abundant fishes captured. These observations suggest that Mid-Atlantic Bight estuaries are important nurseries for juvenile stages beyond the first year, as well as for the young of the year (YOY). Although many other studies emphasise the importance of estuaries as nurseries for YOY stages, the importance of estuaries to later juvenile life stages has been largely overlooked. This component of estuarine fish fauna has been poorly represented in previous North American studies because of probable gear avoidance, and because most studies are conducted primarily during the day. The authors hypothesise that these later juvenile stages are likely to be important estuarine faunal components in other geographic regions, as well as in the Mid-Atlantic Bight. A descriptive comparison of catches between ebb and flood tide stages, and between bay shoal and tidal marsh creek habitats, suggests that later juvenile and adult stages of several species make tidal migrations into shallow estuarine habitats, such as shoals and marsh creeks, during the night hours.

  3. New Mediterranean Biodiversity Records (April, 2014

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    K. KAPIRIS

    2013-12-01

    Full Text Available According to reports, the following 16 species have extended their distribution to other Mediterranean areas or have made a new appearance in other regions. The first category includes the following organisms: The rare and common Indo-Pacific seaweed Codium arabicum (Lebanese coasts, the acari Thalassarachna affinis (Marmara Sea, and the non-indigenous nudibranch Flabellina rubrolineata, which has also been found in many other areas of the Aegean Sea. In addition, the rare sea slug Thecacera pennigera (Piccolo of Taranto, the fangtooth moray Enchelycore anatina (National Marine Park of Zakynthos, Ionian Sea, the carangid Seriola fasciata (Gulf of Antalya, Lagocephalus sceleratus (SE. Ionian Sea, the reticulated leatherjacket Stephanolepis diaspros (Slovenia, N. Adriatic Sea, the marbled stingray, Dasyatis marmorata (NE Levantine, the starry smooth-hound Mustelus asterias (Iskenderun Bay, NE Mediterranean, the cephalopod Ommastrephes bartramii (Ionian Sea have also been reported. The Atlantic crab Dyspanopeus sayi has expanded to many Italian areas and the blue crab Callinectes sapidus to a lake in N. Greece and in the S. Adriatic Sea. Finally, Farfantepenaeus aztecus has been found in the Ionian Sea, thus showing its wide expansion in the Mediterranean. The larval stages of Faccionella oxyrhyncha have been found, after many years, in the Aegean Sea and the first report of an existence on intersexual acari Litarachna duboscqi in Split(Adriatic Sea was reported.

  4. APORTES A LA BIOLOGÍA DE TIBURONES Y RAYAS DEMERSALES EN LA REGIÓN NORTE DEL CARIBE COLOMBIANO

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    Acevedo Kelly

    2008-12-01

    Full Text Available El presente estudio es una contribución al conocimiento biológico de los peces cartilaginosos en la región norte del Caribe colombiano. Los ejemplares examinados se capturaron con una red demersal, se determinó su peso, longitud total y estado de madurez sexual. Adicionalmente se realizó la ubicación espacial de las capturas y la relación con las variables ambientales. Se capturaron un total de 21 individuos, colectando tres especies de rayas, Dasyatis americana, D. guttata y Rhinobatos percellens, dos de tiburones Mustelus minicanis y Rhizoprionodon porosus, la más común fue D. guttata con 56%, las tallas (longitud total fluctuaron entre los 1.760 - 394 mm en rayas y 595 - 585 mm en tiburones. Se obtuvieron más hembras que machos para todas las especies, con predominio de estados inmaduros y en maduración, solo se registró una hembra grávida deM. Minicanis con dos embriones.

  5. A new combination and a new species of onchobothriid tapeworm (Cestoda: Tetraphyllidea: Onchobothriidae) from triakid sharks.

    Science.gov (United States)

    Kurashima, Akira; Shimizu, Toshiya; Mano, Nobuhiro; Ogawa, Kazuo; Fujita, Toshihiko

    2014-05-01

    A new combination and a new species of onchobothriid tapeworm are described from triakid sharks. We found Platybothrium xiamenensis Wang & Yang, 2001 and Erudituncus musteli (Yamaguti, 1952) from Hemitriakis japanica (Müller & Henle). Based on the morphology of the hooks P. xiamenensis is transferred to the genus Erudituncus Healy, Scholz & Caira, 2001. The specimens studied by us differ from the original description in the number of proglottids and testes and in the size of the cirrus-sac. However, we consider them conspecific with E. xiamenensis due to the consistent hook morphology and laciniations in both descriptions and believe the differences reflect intraspecific variation. The type-host of E. xiamenensis was reported as Mustelus griseus Pietschmann. However, in the present study, this parasite was found only in H. japanica and never in M. griseus although many specimens of the latter host were examined. This suggests that the type-host in the original description has probably been misidentified. We found another undescribed species in M. griseus, Calliobothrium shirozame n. sp., which is distinguished from the congeners by having a unique combination of the number of laciniations: four in the cephalic peduncle, six in the immature proglottids and four in the mature proglottids.

  6. APORTES A LA BIOLOGÍA DE TIBURONES Y RAYAS DEMERSALES EN LA REGIÓN NORTE DEL CARIBE COLOMBIANO

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    FABIÁN MORENO RODRÍGUEZ

    2008-01-01

    Full Text Available El presente estudio es una contribución al conocimiento biológico de los peces cartilaginosos en la región norte del Caribe colombiano. Los ejemplares examinados se capturaron con una red demersal, se determinó su peso, longitud total y estado de madurez sexual. Adicionalmente se realizó la ubicación espacial de las capturas y la relación con las variables ambientales. Se capturaron un total de 21 individuos, colectando tres especies de rayas, Dasyatis americana, D. guttata y Rhinobatos percellens, dos de tiburones Mustelus minicanis y Rhizoprionodon porosus, la más común fue D. guttata con 56%, las tallas (longitud total fluctuaron entre los 1.760 - 394 mm en rayas y 595 - 585 mm en tiburones. Se obtuvieron más hembras que machos para todas las especies, con predominio de estados inmaduros y en maduración, solo se registró una hembra grávida de M. minicanis con dos embriones.

  7. The fish tail as a derivation from axial musculoskeletal anatomy: an integrative analysis of functional morphology.

    Science.gov (United States)

    Flammang, B E

    2014-02-01

    The adult morphology of the tail varies greatly among extant fishes despite sharing both ontogenetic similarities and the functional need to propel the body through a fluid medium. Both sharks (Chondrichthyes) and ray-finned fishes (Actinopterygii) control caudal fin musculature independently of axial body myomere activity to modify the stiffness and shape of their tails. For example, sharks and bony fishes possess different structural elements and muscles and move their tails in different ways, resulting in different locomotory hydrodynamic effects and a range of performance variables including speed and maneuverability. The stiffness of the heterocercal, lobate tail of the shark can be modulated during the tail beat resulting in nearly continuous thrust production. In contrast, the highly flexible tail of ray-finned fishes can be manipulated into many different shape conformations enabling increased maneuverability for these fishes. Consequently, the developmental, morphological, and functional derivation of the tail from the axial trunk has resulted in a diversity of form, the attributes of which may be of ecological and evolutionary significance.

  8. Gross anatomy and histology of the olfactory rosette of the shark Heptranchias perlo.

    Science.gov (United States)

    Ferrando, Sara; Gallus, Lorenzo; Amaroli, Andrea; Gambardella, Chiara; Waryani, Baradi; Di Blasi, Davide; Vacchi, Marino

    2017-02-17

    Sharks belonging to the family Hexanchidae have six or seven gill slits, unlike all other elasmobranchs, which have five gill slits. Their olfactory organs have a round shape, which is common for holocephalans, but not for elasmobranchs. Thus, the shape of the olfactory organ represents a further, less striking, peculiarity of this family among elasmobranchs. Despite that, the microscopic anatomy and histology of the olfactory organ have not yet been studied in any species of this family. Here, an anatomical and histological description of the olfactory organ of the sharpnose sevengill shark Heptranchias perlo is given. The organ is a rosette, with a central raphe and 31-34 primary lamellae, which bear secondary lamellae with a more or less branched shape. The elastic connective capsule which envelops the olfactory rosette possibly changes its shape along with water influx. In the olfactory epithelium, the supporting cells also have a secretory function, while no specialized mucous cells are visible; regarding this feature the olfactory epithelium of H. perlo differs from that of other chondrichthyan species. The immunohistochemical investigation of the sensory epithelium shows the absence of immunoreactivity for Gαolf in receptor neurons, which confirms previous observations in Chondrichthyes.

  9. A Severe Accident Caused by an Ocellate River Stingray (Potamotrygon motoro in Central Brazil: How Well Do We Really Understand Stingray Venom Chemistry, Envenomation, and Therapeutics?

    Directory of Open Access Journals (Sweden)

    Nelson Jorge da Silva

    2015-06-01

    Full Text Available Freshwater stingrays cause many serious human injuries, but identification of the offending species is uncommon. The present case involved a large freshwater stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae, in the Araguaia River in Tocantins, Brazil. Appropriate first aid was administered within ~15 min, except that an ice pack was applied. Analgesics provided no pain relief, although hot compresses did. Ciprofloxacin therapy commenced after ~18 h and continued seven days. Then antibiotic was suspended; however, after two more days and additional tests, cephalosporin therapy was initiated, and proved successful. Pain worsened despite increasingly powerful analgesics, until debridement of the wound was performed after one month. The wound finally closed ~70 days after the accident, but the patient continued to have problems wearing shoes even eight months later. Chemistry and pharmacology of Potamotrygon venom and mucus, and clinical management of freshwater stingray envenomations are reviewed in light of the present case. Bacterial infections of stingray puncture wounds may account for more long-term morbidity than stingray venom. Simultaneous prophylactic use of multiple antibiotics is recommended for all but the most superficial stingray wounds. Distinguishing relative contributions of venom, mucus, and bacteria will require careful genomic and transcriptomic investigations of stingray tissues and contaminating bacteria.

  10. Presence of the delta-MSH sequence in a proopiomelanocortin cDNA cloned from the pituitary of the galeoid shark, Heterodontus portusjacksoni.

    Science.gov (United States)

    Dores, Robert M; Cameron, Erin; Lecaude, Stephanie; Danielson, Phillip B

    2003-08-01

    Since a fourth MSH sequence, delta-MSH, has been detected in the proopiomelanocortin (POMC) gene of a dogfish and a stingray, members of superorder Squalea (class Chondrichthyes), it is possible that this novel MSH sequence might be a feature common to the POMC genes of all modern sharks and rays. As an initial step towards addressing this question, a full-length POMC cDNA was cloned and sequenced from the pituitary of the Port Jackson shark, Heterodontus portusjacksoni. The Port Jackson shark represents one of the oldest lineages in superorder Galea, and this superorder together with superorder Squalea form infraclass Neoselachii (the extant sharks and rays). The Port Jackson shark POMC cDNA has an open reading frame that is 1032 nucleotides in length and encodes the deduced amino acids sequences for beta-endorphin, ACTH/alpha-MSH, beta-MSH, gamma-MSH, and delta-MSH. Port Jackson shark delta-MSH has 83% primary sequence identity with dogfish and stingray delta-MSH, and it appears that the delta-MSH sequence may have been the result of an internal domain duplication and reinsertion of the beta-MSH sequence. The presence of the delta-MSH sequence in the POMC genes of representatives of both superorders of infraclass Neoselachii would indicate that the delta-MSH sequence must have been present in the ancestral euselachian shark that gave rise to the neoselachian radiation.

  11. Runx family genes in a cartilaginous fish, the elephant shark (Callorhinchus milii.

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    Giselle Sek Suan Nah

    Full Text Available The Runx family genes encode transcription factors that play key roles in hematopoiesis, skeletogenesis and neurogenesis and are often implicated in diseases. We describe here the cloning and characterization of Runx1, Runx2, Runx3 and Runxb genes in the elephant shark (Callorhinchus milii, a member of Chondrichthyes, the oldest living group of jawed vertebrates. Through the use of alternative promoters and/or alternative splicing, each of the elephant shark Runx genes expresses multiple isoforms similar to their orthologs in human and other bony vertebrates. The expression profiles of elephant shark Runx genes are similar to those of mammalian Runx genes. The syntenic blocks of genes at the elephant shark Runx gene loci are highly conserved in human, but represented by shorter conserved blocks in zebrafish indicating a higher degree of rearrangements in this teleost fish. Analysis of promoter regions revealed conservation of binding sites for transcription factors, including two tandem binding sites for Runx that are totally conserved in the distal promoter regions of elephant shark Runx1-3. Several conserved noncoding elements (CNEs, which are putative cis-regulatory elements, and miRNA binding sites were identified in the elephant shark and human Runx gene loci. Some of these CNEs and miRNA binding sites are absent in teleost fishes such as zebrafish and fugu. In summary, our analysis reveals that the genomic organization and expression profiles of Runx genes were already complex in the common ancestor of jawed vertebrates.

  12. Allergenicity of bony and cartilaginous fish - molecular and immunological properties.

    Science.gov (United States)

    Stephen, J N; Sharp, M F; Ruethers, T; Taki, A; Campbell, D E; Lopata, A L

    2017-03-01

    Allergy to bony fish is common and probably increasing world-wide. The major heat-stable pan-fish allergen, parvalbumin (PV), has been identified and characterized for numerous fish species. In contrast, there are very few reports of allergic reactions to cartilaginous fish despite widespread consumption. The molecular basis for this seemingly low clinical cross-reactivity between these two fish groups has not been elucidated. PV consists of two distinct protein lineages, α and β. The α-lineage of this protein is predominant in muscle tissue of cartilaginous fish (Chondrichthyes), while β-PV is abundant in muscle tissue of bony fish (Osteichthyes). The low incidence of allergic reactions to ingested rays and sharks is likely due to the lack of molecular similarity, resulting in reduced immunological cross-reactivity between the two PV lineages. Structurally and physiologically, both protein lineages are very similar; however, the amino acid homology is very low with 47-54%. Furthermore, PV from ancient fish species such as the coelacanth demonstrates 62% sequence homology to leopard shark α-PV and 70% to carp β-PV. This indicates the extent of conservation of the PV isoforms lineages across millennia. This review highlights prevalence data on fish allergy and sensitization to fish, and details the molecular diversity of the two protein lineages of the major fish allergen PV among different fish groups, emphasizing the immunological and clinical differences in allergenicity.

  13. Effects of urea on the molecules involved in the olfactory signal transduction: a preliminary study on Danio rerio.

    Science.gov (United States)

    Ferrando, Sara; Gallus, Lorenzo; Gambardella, Chiara; Marchesotti, Emiliano; Ravera, Silvia; Franceschini, Valeria; Masini, Maria Angela

    2014-12-01

    Among vertebrates, the physiologically uremic Chondrichthyes are the only class which are not presenting the ciliated olfactory receptor neurons in the olfactory neuroepithelium. The only sequenced genome for this class revealed only three olfactory receptor genes and the immunohistochemical detection of G protein alpha subunit typically coupled to the olfactory receptors (Gα(olf)) failed in different species. Chronic renal disease can represent a cause of olfactory impairment in human. In this context, our present study focused on investigating potential effects of high urea concentration on the olfactory epithelium of vertebrates. Larvae of the teleost fish Danio rerio were exposed to urea in order to assess the effects on the olfactory signal transduction; in particular on both the olfactory receptors and the Gα(olf). The endocytosis of neutral red dye in the olfactory mucosa was detected in control and urea-exposed larvae. The amount of neutral red dye uptake was used as a marker of binding and internalization of the Gα(olf). The neutral red dye endocytosis was not affected by urea exposure, hence suggesting that the presence of the Gα(olf) and their binding to the odorants are not affected by urea treatment, either. The presence and distribution of Gα(olf) were investigated in the olfactory epithelium of control and urea-exposed larvae, using a commercial antibody. The immunoreactivity was increased after urea treatment, suggesting an effect of urea on the expression or degradation of this G protein alpha subunit.

  14. Amphibian and Paleoisciforms from the Lower Part of the Taquaral Member of the Permian Irati Formation, São Paulo State, Brazil

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    Artur Chahud

    2010-03-01

    Full Text Available In the east-central region of the State of São Paulo, Brazil, good exposures of Permo-Carboniferous sequences of theParaná intracratonic basin are found. These sequences start with the Tubarão Supergroup deposits, the PermocarboniferousItararé Group, and the earliest Permian Guatá Group, of which the Tatuí Formation is the only unit occurring in the Stateof São Paulo. The Permian Passa Dois Group overlies the Tubarão Supergroup, with the Early Permian Irati Formation andthe Middle Permian Corumbataí Formation. Two members are recognized in the Irati Formation, Taquaral and Assistência.Most beds of the Taquaral Member are gray laminated siltic-argillaceous, but sandstone beds are present in lower outcropsof this member. One of these sandstones, 9.5 cm thick unconformably overlying sedimentos of the Tatuí Formation, exhibitsdiversifi ed vertebrate remains. The present paper deals with a Palaeonisciformes mandible fragment, one amphibianTemnospondyli tooth, and one Temnospondyli mandible fragment. These fossils are associated to Chondrichthyes andOsteichthyes. It is an open question whether the Parnaíba Basin Palaeonisciformes Brasilichthys macrognathus and theTemnospondyli Prionosuchus plummery belong to the same taxa of the Paraná Basin fossils. Only better preserved fossilsmight solve this question.

  15. Coding early naturalists' accounts into long-term fish community changes in the Adriatic Sea (1800-2000.

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    Tomaso Fortibuoni

    Full Text Available The understanding of fish communities' changes over the past centuries has important implications for conservation policy and marine resource management. However, reconstructing these changes is difficult because information on marine communities before the second half of the 20(th century is, in most cases, anecdotal and merely qualitative. Therefore, historical qualitative records and modern quantitative data are not directly comparable, and their integration for long-term analyses is not straightforward. We developed a methodology that allows the coding of qualitative information provided by early naturalists into semi-quantitative information through an intercalibration with landing proportions. This approach allowed us to reconstruct and quantitatively analyze a 200-year-long time series of fish community structure indicators in the Northern Adriatic Sea (Mediterranean Sea. Our analysis provides evidence of long-term changes in fish community structure, including the decline of Chondrichthyes, large-sized and late-maturing species. This work highlights the importance of broadening the time-frame through which we look at marine ecosystem changes and provides a methodology to exploit, in a quantitative framework, historical qualitative sources. To the purpose, naturalists' eyewitness accounts proved to be useful for extending the analysis on fish community back in the past, well before the onset of field-based monitoring programs.

  16. By-catch composition of the Patagonian scallop fishery: the fishes Composición de la captura incidental en la pesquería de vieira patagónica: los peces

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    Laura Schejter

    2012-11-01

    Full Text Available An inventory of 24 fish species incidentally caught by the Patagonian scallop fleet in the SW Atlantic Ocean is provided for the first time. The most frequent species were Psammobatis spp. (81.4%, Bathyraja brachyurops (75.1%, B. macloviana (73.5%, Patagonotothen ramsayi (66.1%, Merluccius hubbsi (53.7% and B. albomaculata (50.3%. Many of the recorded chondrichthyes are considered vulnerable or endangered species. The number of taxa (fishes + invertebrates that conforms the by-catch of the fishery was increased and updated to nearly 200 species.Este estudio presenta por primera vez un inventario con 24 especies de peces registradas en la captura incidental de la pesca de la vieira patagónica en el Océano Atlántico sudoccidental por la flota pesquera comercial. Las especies más frecuentes fueron Psammobatis spp. (81,4%, Bathyraja brachyurops (75,1%, B. macloviana (73,5%, Patagonotothen ramsayi (66,1%, Merluccius hubbsi (53,7% y B. albomaculata (50,3%. Muchos de los condrictios registrados se encuentran actualmente considerados como especies vulnerables o en peligro. El número de taxa (peces + invertebrados que conforman la captura incidental de esta pesquería se incrementó y actualizó con estos resultados a aproximadamente 200 especies.

  17. Hedgehog signaling patterns the outgrowth of unpaired skeletal appendages in zebrafish

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    Ahlberg Per

    2007-06-01

    Full Text Available Abstract Background Little is known about the control of the development of vertebrate unpaired appendages such as the caudal fin, one of the key morphological specializations of fishes. Recent analysis of lamprey and dogshark median fins suggests the co-option of some molecular mechanisms between paired and median in Chondrichthyes. However, the extent to which the molecular mechanisms patterning paired and median fins are shared remains unknown. Results Here we provide molecular description of the initial ontogeny of the median fins in zebrafish and present several independent lines of evidence that Sonic hedgehog signaling emanating from the embryonic midline is essential for establishment and outgrowth of the caudal fin primordium. However, gene expression analysis shows that the primordium of the adult caudal fin does not harbor a Sonic hedgehog-expressing domain equivalent to the Shh secreting zone of polarizing activity (ZPA of paired appendages. Conclusion Our results suggest that Hedgehog proteins can regulate skeletal appendage outgrowth independent of a ZPA and demonstrates an unexpected mechanism for mediating Shh signals in a median fin primordium. The median fins evolved before paired fins in early craniates, thus the patterning of the median fins may be an ancestral mechanism that controls the outgrowth of skeletogenic appendages in vertebrates.

  18. Evolutionary Relations of Hexanchiformes Deep-Sea Sharks Elucidated by Whole Mitochondrial Genome Sequences

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    Keiko Tanaka

    2013-01-01

    Full Text Available Hexanchiformes is regarded as a monophyletic taxon, but the morphological and genetic relationships between the five extant species within the order are still uncertain. In this study, we determined the whole mitochondrial DNA (mtDNA sequences of seven sharks including representatives of the five Hexanchiformes, one squaliform, and one carcharhiniform and inferred the phylogenetic relationships among those species and 12 other Chondrichthyes (cartilaginous fishes species for which the complete mitogenome is available. The monophyly of Hexanchiformes and its close relation with all other Squaliformes sharks were strongly supported by likelihood and Bayesian phylogenetic analysis of 13,749 aligned nucleotides of 13 protein coding genes and two rRNA genes that were derived from the whole mDNA sequences of the 19 species. The phylogeny suggested that Hexanchiformes is in the superorder Squalomorphi, Chlamydoselachus anguineus (frilled shark is the sister species to all other Hexanchiformes, and the relations within Hexanchiformes are well resolved as Chlamydoselachus, (Notorynchus, (Heptranchias, (Hexanchus griseus, H. nakamurai. Based on our phylogeny, we discussed evolutionary scenarios of the jaw suspension mechanism and gill slit numbers that are significant features in the sharks.

  19. The toxinology of stingrays

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    Gholamhossein Mohebbi

    2016-09-01

    Full Text Available Background: Stingrays belong to Chondrichthyes class.They live in freshwaters and oceans all over the world. They have venomous spines next to the root of the tail. Their barbed stingers covered with secretory cells that cause a large number of serious human injuries. In this review, we evaluate the toxinology of these venomous animals. Results: Some of inoculated venom symptoms included the immediate and intense pain, inflammation and skin necrosis, bleeding wounds, acute edema, salivation, nausea, vomiting, diarrhea, fever, headaches, muscle cramps, tremors, paralysis, dyspnea, cardiovascular collapse, local vasoconstriction, seizures, coma, and rarely death. The venom contains 5-HT, 5-nucleotidase, acetylcholine , phosphodiesterase, proteolytic enzymes against casein, gelatin, and fibrinogen, and several toxins such as cystatins, galectin, peroxiredoxin 6, orpotrin and porflan, and other peptids and proteins including alpha subunit haemoglobin, ganglioside GM2 activator, glutathione s-transferase µ, leukocyte elastase inhibitor, transaldolase, ATP synthase, nucleoside diphosphate kinase and type III intermediate filament. Galectin has a diverse functions including anticoagulant, procoagulant, platelet-modulating, myotoxic and haemagglutination activities. Cystatins are potent inhibitors of cysteine proteinases, including papain and the cathepsins. Hydrolysis of lipids through PLA2 activity is one of the most important functions of peroxiredoxin-6. Orpotrin and porflan have vasoconstrictive and inflammatory effects, respectively. Conclusion: Stingray venoms have different toxins and bioactive molecules with diverse mechanisms of toxicities. A thorough understanding of the toxicities mechanisms and clinical manifestations of stingrays’ venoms will provide the ability to treat effectively and manage injuries with this animals by clinicians and toxinologists.

  20. The epidemiology, evaluation, and management of stingray injuries.

    Science.gov (United States)

    Diaz, James H

    2007-01-01

    A descriptive analysis and review of the world's salient scientific literature on stingray injuries was conducted in light of recent high-profile cases of fatal and near-fatal thoracic stingray injuries to guide clinicians in evaluating and managing stingray injuries. Data was extracted from observational and longitudinal studies over the period, 1950-2006, to permit (1) a stratification of stingray injuries as bites, penetrating lacerations with and without envenoming, and combinations of deeply penetrating and envenoming wounds; and (2) an assessment of new management strategies for thoracoabdominal penetrating trauma and non-healing, necrotic stingray wounds. Unlike their Chondrichthyes classmates, the sharks, stingrays are docile and non-aggressive; and will not attack with their spined tails, unless provoked. Although some occupations are predisposed to stingray injuries, most stingray injuries can be avoided by observing seafloors and adopting simple practices when wading, swimming, diving, or fishing in temperate oceans and some tropical freshwater river systems. All stingray injuries should be managed initially with wound irrigation to dislodge retained spine fragments and envenoming tissues and warm water immersion to inactivate heat-labile toxins.

  1. A Severe Accident Caused by an Ocellate River Stingray (Potamotrygon motoro) in Central Brazil: How Well Do We Really Understand Stingray Venom Chemistry, Envenomation, and Therapeutics?

    Science.gov (United States)

    da Silva, Nelson Jorge; Ferreira, Kalley Ricardo Clementino; Pinto, Raimundo Nonato Leite; Aird, Steven Douglas

    2015-06-18

    Freshwater stingrays cause many serious human injuries, but identification of the offending species is uncommon. The present case involved a large freshwater stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae), in the Araguaia River in Tocantins, Brazil. Appropriate first aid was administered within ~15 min, except that an ice pack was applied. Analgesics provided no pain relief, although hot compresses did. Ciprofloxacin therapy commenced after ~18 h and continued seven days. Then antibiotic was suspended; however, after two more days and additional tests, cephalosporin therapy was initiated, and proved successful. Pain worsened despite increasingly powerful analgesics, until debridement of the wound was performed after one month. The wound finally closed ~70 days after the accident, but the patient continued to have problems wearing shoes even eight months later. Chemistry and pharmacology of Potamotrygon venom and mucus, and clinical management of freshwater stingray envenomations are reviewed in light of the present case. Bacterial infections of stingray puncture wounds may account for more long-term morbidity than stingray venom. Simultaneous prophylactic use of multiple antibiotics is recommended for all but the most superficial stingray wounds. Distinguishing relative contributions of venom, mucus, and bacteria will require careful genomic and transcriptomic investigations of stingray tissues and contaminating bacteria.

  2. Tooth development and histology patterns in lamniform sharks (Elasmobranchii, Lamniformes) revisited.

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    Schnetz, Lisa; Pfaff, Cathrin; Kriwet, Jürgen

    2016-12-01

    The dentition of lamniforme sharks exhibits several characters that have been used extensively to resolve the phylogenetic relationships of extant taxa, yet some uncertainties remain. Also, the development of different teeth of a tooth file within the jaws of most extant lamniforms has not been documented to date. High-resolution micro-computed tomography is used here to re-evaluate the importance of two dental characters within the order Lamniformes, which were considered not to be phylogenetically informative, the histotype and the number of teeth per tooth file. Additionally, the development and mineralization patterns of the teeth of the two osteodont lamniforms Lamna nasus and Alopias superciliosus were compared. We discuss the importance of these dental characters for phylogenetic interpretations to assess the quality of these characters in resolving lamniform relationships. The dental characters suggest that (1) Lamniformes are the only modern-level sharks exhibiting the osteodont histotype, (2) the osteodont histotype in lamniform sharks is a derived state in modern-level sharks (Elasmobranchii), (3) the osteodont type, conversely is convergently achieved when the clade Chondrichthyes is considered and thus might comprise a functional rather than a phylogenetic signal, and (4) there is an increase in the number of teeth per file throughout lamniform phylogeny. Structural development of the teeth of L. nasus and A. superciliosus is congruent with a previous investigation of the lamniform shark Carcharodon carcharias. J. Morphol. 277:1584-1598, 2016. © 2016 Wiley Periodicals, Inc.

  3. Biometric characterization of sharks of the genus Sphyrna (Griffith & Smith, 1834 on the coast of Sergipe

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    Jéssica Barros Andrade

    2016-05-01

    Full Text Available Sharks, rays and chimeras belonging to the subclass Elasmobranchii of the class Chondrichthyes have a slow maturation and development, and they are animals often caught as by-catch, making them vulnerable to extinction. Six species of the genus Sphyrna are found in Brazil, in the coastal-oceanic zone, three of which were studied: Sphyrna lewini, S. mokarran and S. tiburo. This study aimed to evaluate the biometrics, sex and stage of sexual development of the genus Sphyrna in artisanal fishing in Aracaju (SE. The animals used included specimens from the GEES collection and fresh ones acquired from local fisheries. S. tiburo was found only in the collection. The species S. mokarran and S. lewini included more newborn individuals and males and S. tiburo more females and juveniles. In fresh species, pectoral-pelvic length was greater in females, and pelvic-anal length was greater in males of S. lewini. Weight was greatest in S. lewini, while there was no difference in total length, head width and interdorsal length between specimens. The parameters measured did not show significant results that could be related to by-catch with many immature individuals.

  4. Evolution of melanocortin receptors in cartilaginous fish: melanocortin receptors and the stress axis in elasmobranches.

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    Liang, Liang; Reinick, Christina; Angleson, Joseph K; Dores, Robert M

    2013-01-15

    There is general agreement that the presence of five melanocortin receptor genes in tetrapods is the result of two genome duplications that occurred prior to the emergence of the gnathostomes, and at least one local gene duplication that occurred early in the radiation of the ancestral gnathostomes. Hence, it is assumed that representatives from the extant classes of gnathostomes (i.e., Chondrichthyes, Actinopterygii, Sarcopterygii) should also have five paralogous melanocortin genes. Current studies on cartilaginous fishes indicate that while there is evidence for five paralogous melanocortin receptor genes in this class, to date all five paralogs have not been detected in the genome of a single species. This mini-review will discuss the ligand selectivity properties of the melanocortin-3 receptor of the elephant shark (subclass Holocephali) and the ligand selectivity properties of the melanocortin-3 receptor, melanocortin-4 receptor, and the melanocortin-5 receptor of the dogfish (subclass Elasmobranchii). The potential relationship of these melanocortin receptors to the hypothalamus/pituitary/interrenal axis will be discussed.

  5. Basal Gnathostomes Provide Unique Insights into the Evolution of Vitamin B12 Binders

    Science.gov (United States)

    Lopes-Marques, Mónica; Ruivo, Raquel; Delgado, Inês; Wilson, Jonathan M.; Aluru, Neelakanteswar; Castro, L. Filipe C.

    2015-01-01

    The uptake and transport of vitamin B12 (cobalamin; Cbl) in mammals involves a refined system with three evolutionarily related transporters: transcobalamin 1 (Tcn1), transcobalamin 2 (Tcn2), and the gastric intrinsic factor (Gif). Teleosts have a single documented binder with intermediate features to the human counterparts. Consequently, it has been proposed that the expansion of Cbl binders occurred after the separation of Actinopterygians. Here, we demonstrate that the diversification of this gene family took place earlier in gnathostome ancestry. Our data indicates the presence of single copy orthologs of the Sarcopterygii/Tetrapoda duplicates Tcn1 and Gif, and Tcn2, in Chondrichthyes. In addition, a highly divergent Cbl binder was found in the Elasmobranchii. We unveil a complex scenario forged by genome, tandem duplications and lineage-specific gene loss. Our findings suggest that from an ancestral transporter, exhibiting large spectrum and high affinity binding, highly specific Cbl transporters emerged through gene duplication and mutations at the binding pocket. PMID:25552533

  6. Structure, function and molecular adaptations of haemoglobins of the polar cartilaginous fish Bathyraja eatonii and Raja hyperborea.

    Science.gov (United States)

    Verde, Cinzia; De Rosa, M Cristina; Giordano, Daniela; Mosca, Donato; De Pascale, Donatella; Raiola, Luca; Cocca, Ennio; Carratore, Vitale; Giardina, Bruno; Di Prisco, Guido

    2005-07-15

    Cartilaginous fish are very ancient organisms. In the Antarctic sea, the modern chondrichthyan genera are poorly represented, with only three species of sharks and eight species of skates; the paucity of chondrichthyans is probably an ecological consequence of unusual trophic or habitat conditions in the Southern Ocean. In the Arctic, there are 26 species belonging to the class Chondrichthyes. Fish in the two polar regions have been subjected to different regional histories that have influenced the development of diversity: Antarctic marine organisms are highly stenothermal, in response to stable water temperatures, whereas the Arctic communities are exposed to seasonal temperature variations. The structure and function of the oxygen-transport haem protein from the Antarctic skate Bathyraja eatonii and from the Arctic skate Raja hyperborea (both of the subclass Elasmobranchii, order Rajiformes, family Rajidae) is reported in the present paper. These species have a single major haemoglobin (Hb 1; over 80% of the total). The Bohr-proton and the organophosphate-binding sites are absent. Thus the haemoglobins of northern and southern polar skates appear functionally similar, whereas differences were observed with several temperate elasmobranchs. Such evidence suggests that, in temperate and polar habitats, physiological adaptations have evolved along distinct pathways, whereas, in this case, the effect of the differences characterizing the two polar environments is negligible.

  7. Thyroid hormone deiodination in fish.

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    Orozco, Aurea; Valverde-R, Carlos

    2005-08-01

    We review the experimental evidence accumulated within the past decade regarding the physiologic, biochemical, and molecular characterization of iodothyronine deiodinases (IDs) in piscine species. Agnathans, chondrichthyes, and teleosts express the three isotypes of IDs: ID1, ID2, and ID3, which are responsible for the peripheral fine-tuning of thyroid hormone (TH) bioactivity. At the molecular and operational level, fish IDs share properties with their corresponding vertebrate counterparts. However, fish IDs also exhibit discrete features that seem to be distinctive for piscine species. Indeed, teleostean ID1 is conspicuously resistant to propylthiouracil (PTU) inhibition, and its response to thyroidal status differs from that exhibited by other ID1s. Moreover, both the high level of ID2 activity and its expression in the liver of teleosts are unique among vertebrates. The physiologic role of iodothyronine deiodination in functions regulated by TH in fish is not entirely clear. Nevertheless, current experimental evidence suggests that IDs may coordinate and facilitate, in a tissue-specific fashion, the action of iodothyronines and other hormones involved in such processes.

  8. Relação dos peixes coletados nos limites da plataforma continental e nas montanhas submarinas Vitória, Trindade e Martin Vaz, durante a campanha oceanográfica MD-55 Brasil List of fishes collected at the continental shelf limits Vitória, Trinidade and Martin Vaz seamounts during the MD-55 Brazil oceanographic campaign

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    José V. Andreata

    1995-09-01

    Full Text Available The result of an agreement between Universidade Santa Ursula, Rio de Janeiro and the Museum of Natural History of Paris, was the oceanographic campaign MD-55 Brasil which took place between May 6th and June 2nd of 1987, aboard the R/V "Marion Dufresne" of the Terres Australes et Antartique Françaises (TAAF. Samples were collected between latitudes 23º36'40"S and 18º49'S. Ichthyofauna sampled was relatively low, and comprised of just one family of Chondrichthyes (three species and 50 families of Osteichthyes (104 species. Zenion hololepsis (Goode & Bean, 1895 (Zeniodontidae is recorded for the first time from the western South Atlantic, as well as is extended the geographic limits for Myrophis frio Jordan & Davis. 1892 (Ophichthidae and Prionotus nudigula Ginshurg, 1950 (Triglidae. Even though relatively not very representative, the species collected from the seamount chain Vitoria/Trindade and Martin Vay suggest being identical to those which occur along the Brazilian continental platform.

  9. Diversity of bile salts in fish and amphibians: evolution of a complex biochemical pathway.

    Science.gov (United States)

    Hagey, Lee R; Møller, Peter R; Hofmann, Alan F; Krasowski, Matthew D

    2010-01-01

    Bile salts are the major end metabolites of cholesterol and are also important in lipid and protein digestion, as well as shaping of the gut microflora. Previous studies had demonstrated variation of bile salt structures across vertebrate species. We greatly extend prior surveys of bile salt variation in fish and amphibians, particularly in analysis of the biliary bile salts of Agnatha and Chondrichthyes. While there is significant structural variation of bile salts across all fish orders, bile salt profiles are generally stable within orders of fish and do not correlate with differences in diet. This large data set allowed us to infer evolutionary changes in the bile salt synthetic pathway. The hypothesized ancestral bile salt synthetic pathway, likely exemplified in extant hagfish, is simpler and much shorter than the pathway of most teleost fish and terrestrial vertebrates. Thus, the bile salt synthetic pathway has become longer and more complex throughout vertebrate evolution. Analysis of the evolution of bile salt synthetic pathways provides a rich model system for the molecular evolution of a complex biochemical pathway in vertebrates.

  10. Questioning hagfish affinities of the enigmatic Devonian vertebrate Palaeospondylus

    Science.gov (United States)

    Johanson, Zerina; Smith, Moya; Sanchez, Sophie; Senden, Tim; Trinajstic, Kate; Pfaff, Cathrin

    2017-07-01

    Palaeospondylus gunni Traquair, 1890 is an enigmatic Devonian vertebrate whose taxonomic affinities have been debated since it was first described. Most recently, Palaeospondylus has been identified as a stem-group hagfish (Myxinoidea). However, one character questioning this assignment is the presence of three semicircular canals in the otic region of the cartilaginous skull, a feature of jawed vertebrates. Additionally, new tomographic data reveal that the following characters of crown-group gnathostomes (chondrichthyans + osteichthyans) are present in Palaeospondylus: a longer telencephalic region of the braincase, separation of otic and occipital regions by the otico-occipital fissure, and vertebral centra. As well, a precerebral fontanelle and postorbital articulation of the palatoquadrate are characteristic of certain chondrichthyans. Similarities in the structure of the postorbital process to taxa such as Pucapampella, and possible presence of the ventral cranial fissure, both support a resolution of Pa. gunni as a stem chondrichthyan. The internally mineralized cartilaginous skeleton in Palaeospondylus may represent a stage in the loss of bone characteristic of the Chondrichthyes.

  11. Evolution of the Vertebrate Resistin Gene Family.

    Science.gov (United States)

    Hu, Qingda; Tan, Huanran; Irwin, David M

    2015-01-01

    Resistin (encoded by Retn) was previously identified in rodents as a hormone associated with diabetes; however human resistin is instead linked to inflammation. Resistin is a member of a small gene family that includes the resistin-like peptides (encoded by Retnl genes) in mammals. Genomic searches of available genome sequences of diverse vertebrates and phylogenetic analyses were conducted to determine the size and origin of the resistin-like gene family. Genes encoding peptides similar to resistin were found in Mammalia, Sauria, Amphibia, and Actinistia (coelacanth, a lobe-finned fish), but not in Aves or fish from Actinopterygii, Chondrichthyes, or Agnatha. Retnl originated by duplication and transposition from Retn on the early mammalian lineage after divergence of the platypus, but before the placental and marsupial mammal divergence. The resistin-like gene family illustrates an instance where the locus of origin of duplicated genes can be identified, with Retn continuing to reside at this location. Mammalian species typically have a single copy Retn gene, but are much more variable in their numbers of Retnl genes, ranging from 0 to 9. Since Retn is located at the locus of origin, thus likely retained the ancestral expression pattern, largely maintained its copy number, and did not display accelerated evolution, we suggest that it is more likely to have maintained an ancestral function, while Retnl, which transposed to a new location, displays accelerated evolution, and shows greater variability in gene number, including gene loss, likely evolved new, but potentially lineage-specific, functions.

  12. Evolution of the Vertebrate Resistin Gene Family.

    Directory of Open Access Journals (Sweden)

    Qingda Hu

    Full Text Available Resistin (encoded by Retn was previously identified in rodents as a hormone associated with diabetes; however human resistin is instead linked to inflammation. Resistin is a member of a small gene family that includes the resistin-like peptides (encoded by Retnl genes in mammals. Genomic searches of available genome sequences of diverse vertebrates and phylogenetic analyses were conducted to determine the size and origin of the resistin-like gene family. Genes encoding peptides similar to resistin were found in Mammalia, Sauria, Amphibia, and Actinistia (coelacanth, a lobe-finned fish, but not in Aves or fish from Actinopterygii, Chondrichthyes, or Agnatha. Retnl originated by duplication and transposition from Retn on the early mammalian lineage after divergence of the platypus, but before the placental and marsupial mammal divergence. The resistin-like gene family illustrates an instance where the locus of origin of duplicated genes can be identified, with Retn continuing to reside at this location. Mammalian species typically have a single copy Retn gene, but are much more variable in their numbers of Retnl genes, ranging from 0 to 9. Since Retn is located at the locus of origin, thus likely retained the ancestral expression pattern, largely maintained its copy number, and did not display accelerated evolution, we suggest that it is more likely to have maintained an ancestral function, while Retnl, which transposed to a new location, displays accelerated evolution, and shows greater variability in gene number, including gene loss, likely evolved new, but potentially lineage-specific, functions.

  13. Molecular markers of cancer in cartilaginous fish: immunocytochemical study of PCNA, p-53, myc and ras expression in neoplastic and hyperplastic tissues from free ranging blue sharks, Prionace glauca (L.).

    Science.gov (United States)

    Borucinska, J D; Schmidt, B; Tolisano, J; Woodward, D

    2008-02-01

    Archival formalin-fixed tissues from wild-caught adult blue sharks, Prionace glauca (L.), were used for immunocytochemical detection of proliferating cell nuclear antigen (PCNA), two oncoproteins from the oncogenes c-myc and pan-ras, and a protein product from the tumour suppressor gene p-53. All sharks were caught during summer months between 2000 and 2006 by recreational fishermen off the USA coast in the northwestern Atlantic. The sharks were necropsied on landing and selected organ samples were collected into elasmobranch formalin and processed for paraffin embedding and light microscopy. Paraffin-embedded sections from collected tissue were both stained with haematoxylin and eosin and processed by immunocytochemical techniques using antibodies raised against the PCNA, p-ras, c-myc and p-53 proteins. The lesions examined in this study included two well differentiated adenomatous gastric polyps, a testicular capsular mesothelioma, a gingival fibropapilloma with elements of ameloblastoma, three liver tumours, two pericardial fibropapillomas and six cases of proliferative serositis (pericarditis and peritonitis). Normal and hyperplastic tissues from blue sharks, and human neoplastic tissues served as negative and positive controls, respectively. We detected upregulation of PCNA in many neoplastic, one dysplastic and in some hyperplastic lesions, and positive p-ras and c-myc signals in some of the neoplastic lesions. None of the examined tissues showed positive p-53 signalling. This is the first literature report on immunocytochemical detection of molecular markers of cancer in sharks and in fish of the class Chondrichthyes.

  14. Oldest near-complete acanthodian: the first vertebrate from the Silurian Bertie Formation Konservat-Lagerstatte, Ontario.

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    Carole J Burrow

    Full Text Available The relationships between early jawed vertebrates have been much debated, with cladistic analyses yielding little consensus on the position (or positions of acanthodians with respect to other groups. Whereas one recent analysis showed various acanthodians (classically known as 'spiny sharks' as stem osteichthyans (bony fishes and others as stem chondrichthyans, another shows the acanthodians as a paraphyletic group of stem chondrichthyans, and the latest analysis shows acanthodians as the monophyletic sister group of the Chondrichthyes.A small specimen of the ischnacanthiform acanthodian Nerepisacanthus denisoni is the first vertebrate fossil collected from the Late Silurian Bertie Formation Konservat-Lagerstätte of southern Ontario, Canada, a deposit well-known for its spectacular eurypterid fossils. The fish is the only near complete acanthodian from pre-Devonian strata worldwide, and confirms that Nerepisacanthus has dentigerous jaw bones, body scales with superposed crown growth zones formed of ondontocytic mesodentine, and a patch of chondrichthyan-like scales posterior to the jaw joint.The combination of features found in Nerepisacanthus supports the hypothesis that acanthodians could be a group, or even a clade, on the chondrichthyan stem. Cladistic analyses of early jawed vertebrates incorporating Nerepisacanthus, and updated data on other acanthodians based on publications in press, should help clarify their relationships.

  15. Selection of cholera toxin specific IgNAR single-domain antibodies from a naïve shark library.

    Science.gov (United States)

    Liu, Jinny L; Anderson, George P; Delehanty, James B; Baumann, Richard; Hayhurst, Andrew; Goldman, Ellen R

    2007-03-01

    Shark immunoglobulin new antigen receptor (IgNAR, also referred to as NAR) variable domains (Vs) are single-domain antibody (sdAb) fragments containing only two hypervariable loop structures forming 3D topologies for a wide range of antigen recognition and binding. Their small size ( approximately 12kDa) and high solubility, thermostability and binding specificity make IgNARs an exceptional alternative source of engineered antibodies for sensor applications. Here, two new shark NAR V display libraries containing >10(7) unique clones from non-immunized (naïve) adult spiny dogfish (Squalus acanthias) and smooth dogfish (Mustelus canis) sharks were constructed. The most conserved consensus sequences derived from random clone sequence were compared with published nurse shark (Ginglymostoma cirratum) sequences. Cholera toxin (CT) was chosen for panning one of the naïve display libraries due to its severe pathogenicity and commercial availability. Three very similar CT binders were selected and purified soluble monomeric anti-CT sdAbs were characterized using Luminex(100) and traditional ELISA assays. These novel anti-CT sdAbs selected from our newly constructed shark NAR V sdAb library specifically bound to soluble antigen, without cross reacting with other irrelevant antigens. They also showed superior heat stability, exhibiting slow loss of activity over the course of one hour at high temperature (95 degrees C), while conventional antibodies lost all activity in the first 5-10min. The successful isolation of target specific sdAbs from one of our non-biased NAR libraries, demonstrate their ability to provide binders against an unacquainted antigen of interest.

  16. Feeding ecology of elasmobranch fishes in coastal waters of the Colombian Eastern Tropical Pacific

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    Mejía-Falla Paola A

    2007-09-01

    Full Text Available Abstract Background Stomach contents of 131 specimens of five elasmobranch species (Mustelus lunulatus, Dasyatis longa, Rhinobatos leucorhynchus, Raja velezi and Zapteryx xyster caught in the central fishing zone in the Pacific Ocean of Colombia were counted and weighed to describe feeding habits and dietary overlaps. Results Twenty-one prey items belonging to four major groups (stomatopods, decapods, mollusks and fish were identified. Decapod crustaceans were the most abundant prey found in stomachs. The mantis shrimp Squilla panamensis was the main prey item in the diet of M. lunulatus; tiger shrimp Trachypenaeus sp. was the main prey item in the diet of Rhinobatos leucorhynchus and Raja velezi, and Penaeidae shrimp were the main prey items in the diet of Z. xyster. Furthermore, fish were important in the diet of Raja velezi, Z. xyster and D. longa. The greatest diet breadth corresponded to Z. xyster whereas M. lunulatus was the most specialized predator. Finally, four significant diet overlaps between the five species were found, attributable mainly to Squillidae, Penaeidae and Fish. Conclusion Shrimps (Penaeidae and stomatopods and benthic fishes were the most important food types in the diet of the elasmobranch species studied. Diet breadth and overlap were relatively low. Determination of food resource partitioning among the batoid species studied was not possible. However, we identified partitions in other niche axes (time of feeding activity and habitat utilization. It is possible to assume that diffuse competition could be exceeding the biunivocal competition among the studied species. Therefore, this assemblage would have a strong tendency to trophic guild formation.

  17. Shark fisheries in the Southeast Pacific: A 61-year analysis from Peru.

    Science.gov (United States)

    Gonzalez-Pestana, Adriana; Kouri J, Carlos; Velez-Zuazo, Ximena

    2014-01-01

    Peruvian waters exhibit high conservation value for sharks. This contrasts with a lag in initiatives for their management and a lack of studies about their biology, ecology and fishery. We investigated the dynamics of Peruvian shark fishery and its legal framework identifying information gaps for recommending actions to improve management. Further, we investigated the importance of the Peruvian shark fishery from a regional perspective. From 1950 to 2010, 372,015 tons of sharks were landed in Peru. From 1950 to 1969, we detected a significant increase in landings; but from 2000 to 2011 there was a significant decrease in landings, estimated at 3.5% per year. Six species represented 94% of landings: blue shark ( Prionace glauca), shortfin mako ( Isurus oxyrinchus), smooth hammerhead ( Sphyrna zygaena), common thresher ( Alopias vulpinus), smooth-hound ( Mustelus whitneyi) and angel shark ( Squatina californica). Of these, the angel shark exhibits a strong and significant decrease in landings: 18.9% per year from 2000 to 2010. Peru reports the highest accumulated historical landings in the Pacific Ocean; but its contribution to annual landings has decreased since 1968. Still, Peru is among the top 12 countries exporting shark fins to the Hong Kong market. Although the government collects total weight by species, the number of specimens landed as well as population parameters (e.g. sex, size and weight) are not reported. Further, for some genera, species-level identification is deficient and so overestimates the biomass landed by species and underestimates the species diversity. Recently, regional efforts to regulate shark fishery have been implemented to support the conservation of sharks but in Peru work remains to be done.

  18. Shark fisheries in the Southeast Pacific: A 61-year analysis from Peru [version 2; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    Adriana Gonzalez-Pestana

    2016-04-01

    Full Text Available Peruvian waters exhibit high conservation value for sharks. This contrasts with a lag in initiatives for their management and a lack of studies about their biology, ecology and fishery. We investigated the dynamics of Peruvian shark fishery and its legal framework identifying information gaps for recommending actions to improve management. Further, we investigated the importance of the Peruvian shark fishery from a regional perspective. From 1950 to 2010, 372,015 tons of sharks were landed in Peru. From 1950 to 1969, we detected a significant increase in landings; but from 2000 to 2011 there was a significant decrease in landings, estimated at 3.5% per year. Six species represented 94% of landings: blue shark (Prionace glauca, shortfin mako (Isurus oxyrinchus, smooth hammerhead (Sphyrna zygaena, common thresher (Alopias vulpinus, smooth-hound (Mustelus whitneyi and angel shark (Squatina californica. Of these, the angel shark exhibits a strong and significant decrease in landings: 18.9% per year from 2000 to 2010. Peru reports the highest accumulated historical landings in the Pacific Ocean; but its contribution to annual landings has decreased since 1968. Still, Peru is among the top 12 countries exporting shark fins to the Hong Kong market. Although the government collects total weight by species, the number of specimens landed as well as population parameters (e.g. sex, size and weight are not reported. Further, for some genera, species-level identification is deficient and so overestimates the biomass landed by species and underestimates the species diversity. Recently, regional efforts to regulate shark fishery have been implemented to support the conservation of sharks but in Peru work remains to be done.

  19. Global versus local causes and health implications of high mercury concentrations in sharks from the east coast of South Africa.

    Science.gov (United States)

    McKinney, Melissa A; Dean, Kylie; Hussey, Nigel E; Cliff, Geremy; Wintner, Sabine P; Dudley, Sheldon F J; Zungu, M Philip; Fisk, Aaron T

    2016-01-15

    Conservation concern regarding the overharvest of global shark populations for meat and fin consumption largely surrounds documented deleterious ecosystem effects, but may be further supported by improved knowledge of possibly high levels in their edible tissues (particularly meat) of the neurotoxin, methylmercury (CH3Hg). For many regions, however, little data exist on shark tissue Hg concentrations, and reasons for Hg variation within and among species or across regions are poorly understood. We quantified total Hg (THg) in 17 shark species (total n=283) from the east coast of South Africa, a top Hg emitter globally. Concentrations varied from means of around 0.1 mg kg(-1) dry weight (dw) THg in hardnose smoothhound (Mustelus mosis) and whale (Rhincodon typus) sharks to means of over 10 mg kg(-1) dw in shortfin mako (Isurus oxyrinchus), scalloped hammerhead (Sphyrna lewini), white (Carcharodon carcharias) and ragged-tooth (Carcharias taurus) sharks. These sharks had higher THg levels than conspecifics sampled from coastal waters of the North Atlantic and North, mid-, and South Pacific, and although sampling year and shark size may play a confounding role, this result suggests the potential importance of elevated local emissions. Values of THg showed strong, species-specific correlations with length, and nearly half the remaining variation was explained by trophic position (using nitrogen stable isotopes, δ(15)N), whereas measures of foraging habitat (using carbon stable isotopes, δ(13)C) were not significant. Mercury concentrations were above the regulatory guidelines for fish health effects and safe human consumption for 88% and 70% of species, respectively, suggesting on-going cause for concern for shark health, and human consumers of shark meat.

  20. Evaluación de la pesca de tiburón en Colombia

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    Jarcia Camilo B.

    2007-04-01

    Full Text Available La pesca de tiburón en Colombia ha sido poco documentada y estudiada, contándose solo con unos cuantos
    trabajos realizados por instituciones gubernamentales y algunas universidades. Colombia registra algunos
    de los valores más bajos en cuanto a captura de tiburón en las regiones Caribe y Pacífica, promediando
    valores de 94t y 512t anuales respectivamente; donde la flota industrial captura el 70% y el restante 30%
    corresponde a la flota artesanal. Estas capturas se dan principalmente como pesca incidental de pesquerías
    más grandes (i.e. atún y camarón, aunque existe una pesca dirigida. Las principales artes involucradas son
    el palangre (tanto de fondo como de superficie y la red agallera. En la costa pacífica las principales especies
    capturadas son Sphyrna lewini, Carcharhinus falciformis y las del género Mustelus spp.; mientras en el Caribe
    son especies de los géneros Rhizoprionodon y Carcharhinus. Los principales productos extraídos son las aletas, cuya remoción no es ilegal dentro del territorio nacional, y la carne, siendo las primeras utilizadas solo para
    exportación y las segundas, principalmente, para consumo nacional. No existe información acerca de abundancia, frecuencia, composición y captura por unidad de esfuerzo (CPUE de las especies capturadas. Esta carencia de información genera problemas en el manejo del recurso y exalta la necesidad de iniciar investigaciones que ayuden a llenar los vacíos existentes.

  1. The dismantling of Calliobothrium (Cestoda: Tetraphyllidea) with erection of Symcallio n. gen. and description of two new species.

    Science.gov (United States)

    Bernot, James P; Caira, Janine N; Pickering, Maria

    2015-04-01

    This paper aims to resolve the dual composition of the triakid shark-hosted tetraphyllidean genus Calliobothrium--an issue that has been recognized for over a decade. As it stands, this genus includes a number of large species with laciniate proglottids, most of which bear 3 suckers at the anterior margin of each bothridium, but it also includes a number of species that lack proglottid laciniations and bear only a single sucker per bothridium, most of which are relatively small. Discovery of 2 new species, 1 of each form, parasitizing the whitespot smoothhound shark, Mustelus palumbes, off South Africa, prompted the first molecular analysis of the genus. Bayesian inference and maximum likelihood analyses of 28S rDNA (D1-D3) sequence data generated for specimens of both new species as well as of 2 known species of the laciniate form (Calliobothrium australis and Calliobothrium cf. verticillatum) and 3 known species of the non-laciniate form (Calliobothrium violae, Calliobothrium riseri, and Calliobothrium barbarae) confirmed the reciprocal monophyly of the 2 clades, supporting establishment of a new genus. Because the type of Calliobothrium, C. verticillatum, is of the laciniate form, Symcallio n. gen., with Symcallio peteri n. gen., n. sp., from M. palumbes described as its type, is established to house members of the non-laciniate clade. The 11 described species consistent with this form are transferred to the new genus. A new species of the laciniate clade, Calliobothrium euzeti n. sp., is described from M. palumbes, and a revised diagnosis of Calliobothrium is presented.

  2. Two new species of Echinobothrium van Beneden, 1849 (Cestoda: Diphyllidea) from the Persian Gulf.

    Science.gov (United States)

    Haseli, Mohammad; Malek, Masoumeh; Palm, Harry W; Ivanov, Verónica A

    2012-07-01

    Two new species of diphyllidean cestodes are described from the Persian Gulf, Echinobothrium persiense n. sp. from Rhinobatos punctifer Compagno & Randall and Echinobothrium hormozganiense n. sp. from Mustelus mosis Hemprich & Ehrenberg. E. persiense is the first record of a species of Echinobothrium van Beneden, 1849 from R. punctifer and these two new species increase the number of diphyllideans known from the Persian Gulf from one to three. The number of apical hooks of E. persiense (hook formula: {5-6 6/5 5-6}) is distinct from all other species in the genus except for E. affine Diesing, 1863, E. harfordi McVicar, 1976, E. bonasum Williams & Campbell, 1980, E. fautleyae Tyler & Caira, 1999, E. syrtense (Neifar, Tyler & Euzet, 2001) Tyler, 2006 (emend), E. chisholmae Jones & Beveridge, 2001, E. tetabuanense Ivanov & Caira, 2012, E. sematanense Ivanov & Caira, 2012 and E. weipaense Ivanov & Caira, 2012. Echinobothrium persiense can be distinguished from all other species of the genus with 11 apical hooks by a combination of the following features: armed cephalic peduncle, testes arranged in a single column, lateral hooklets arranged in two groups, U-shaped ovary, cephalic peduncle length (124-181 μm), genital pore and cirrus-sac position, and by having 10-14 spines per row on the cephalic peduncle. Echinobothrium hormozganiense has a hook formula of {12-15 16/15 12-15} and is similar to E. musteli Pintner, 1889, E. notoguidoi Ivanov, 1997 and E. diamanti Ivanov & Lipshitz, 2006 by possessing additional spines between the rostellum and the bothria. It differs from E. musteli by having an H-shaped ovary and lateral hooklets arranged in two lateral groups, and the number of spines per row on the cephalic peduncle (18-21) readily differentiates it from E. notoguidoi (24-26) and E. diamanti (95-118). With these two new species, Echinobothrium van Beneden, 1849 now includes 45 valid species.

  3. Shark fisheries in the Southeast Pacific: A 61-year analysis from Peru

    Science.gov (United States)

    Gonzalez-Pestana, Adriana; Kouri J., Carlos; Velez-Zuazo, Ximena

    2016-01-01

    Peruvian waters exhibit high conservation value for sharks. This contrasts with a lag in initiatives for their management and a lack of studies about their biology, ecology and fishery. We investigated the dynamics of Peruvian shark fishery and its legal framework identifying information gaps for recommending actions to improve management. Further, we investigated the importance of the Peruvian shark fishery from a regional perspective. From 1950 to 2010, 372,015 tons of sharks were landed in Peru. From 1950 to 1969, we detected a significant increase in landings; but from 2000 to 2011 there was a significant decrease in landings, estimated at 3.5% per year. Six species represented 94% of landings: blue shark ( Prionace glauca), shortfin mako ( Isurus oxyrinchus), smooth hammerhead ( Sphyrna zygaena), common thresher ( Alopias vulpinus), smooth-hound ( Mustelus whitneyi) and angel shark ( Squatina californica). Of these, the angel shark exhibits a strong and significant decrease in landings: 18.9% per year from 2000 to 2010. Peru reports the highest accumulated historical landings in the Pacific Ocean; but its contribution to annual landings has decreased since 1968. Still, Peru is among the top 12 countries exporting shark fins to the Hong Kong market. Although the government collects total weight by species, the number of specimens landed as well as population parameters (e.g. sex, size and weight) are not reported. Further, for some genera, species-level identification is deficient and so overestimates the biomass landed by species and underestimates the species diversity. Recently, regional efforts to regulate shark fishery have been implemented to support the conservation of sharks but in Peru work remains to be done. PMID:27635216

  4. Estimating Finite Rate of Population Increase for Sharks Based on Vital Parameters.

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    Kwang-Ming Liu

    Full Text Available The vital parameter data for 62 stocks, covering 38 species, collected from the literature, including parameters of age, growth, and reproduction, were log-transformed and analyzed using multivariate analyses. Three groups were identified and empirical equations were developed for each to describe the relationships between the predicted finite rates of population increase (λ' and the vital parameters, maximum age (Tmax, age at maturity (Tm, annual fecundity (f/Rc, size at birth (Lb, size at maturity (Lm, and asymptotic length (L∞. Group (1 included species with slow growth rates (0.034 yr(-1 < k < 0.103 yr(-1 and extended longevity (26 yr < Tmax < 81 yr, e.g., shortfin mako Isurus oxyrinchus, dusky shark Carcharhinus obscurus, etc.; Group (2 included species with fast growth rates (0.103 yr(-1 < k < 0.358 yr(-1 and short longevity (9 yr < Tmax < 26 yr, e.g., starspotted smoothhound Mustelus manazo, gray smoothhound M. californicus, etc.; Group (3 included late maturing species (Lm/L∞ ≧ 0.75 with moderate longevity (Tmax < 29 yr, e.g., pelagic thresher Alopias pelagicus, sevengill shark Notorynchus cepedianus. The empirical equation for all data pooled was also developed. The λ' values estimated by these empirical equations showed good agreement with those calculated using conventional demographic analysis. The predictability was further validated by an independent data set of three species. The empirical equations developed in this study not only reduce the uncertainties in estimation but also account for the difference in life history among groups. This method therefore provides an efficient and effective approach to the implementation of precautionary shark management measures.

  5. Shark scavenging behavior in the presence of competition

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    Shannon P. GERRY, Andrea J. SCOTT

    2010-02-01

    Full Text Available The distribution of organisms within a community can often be determined by the degree of plasticity or degree of specialization of resource acquisition. Resource acquisition is often based on the morphology of an organism, behavior, or a combination of both. Performance tests of feeding can identify the possible interactions that allow one species to better exploit a prey item. Scavenging behaviors in the presence or absence of a competitor were investigated by quantifying prey selection in a trophic generalist, spiny dogfish Squalus acanthias, and a trophic specialist, smooth-hounds Mustelus canis, in order to determine if each shark scavenged according to its jaw morphology. The diet of dogfish consists of small fishes, squid, ctenophores, and bivalves; they are expected to be nonselective predators. Smooth-hounds primarily feed on crustaceans; therefore, they are predicted to select crabs over other prey types. Prey selection was quantified by ranking each prey item according to the order it was consumed. Dietary shifts were analyzed by comparing the percentage of each prey item selected during solitary versus competitive scavenging. When scavenging alone, dogfish prefer herring and squid, which are easily handled by the cutting dentition of dogfish. Dogfish shift their diet to include a greater number of prey types when scavenging with a competitor. Smooth-hounds scavenge on squid, herring, and shrimp when alone, but increase the number of crabs in the diet when scavenging competitively. Competition causes smooth-hounds to scavenge according to their jaw morphology and locomotor abilities, which enables them to feed on a specialized resource [Current Zoology 56 (1: 100–108 2010].

  6. The invasion of five alien species in the Delta do Parnaíba Environmental Protection Area, Northeastern Brazil.

    Science.gov (United States)

    Loebmann, Daniel; Mai, Ana Cecília G; Lee, James T

    2010-09-01

    Marine biological invasions have been regarded as one of the major causes of native biodiversity loss, with shipping and aquaculture being the leading contributors for the introductions of alien species in aquatic ecosystems. In the present study, five aquatic alien species (one mollusk, three crustaceans and one fish species) were detected during dives, shore searches and from the fisheries on the coast of the Delta do Parnaíba Environmental Protection Area, in the States of Piauí and Maranhão, Northeastern Brazil. The species were the bicolor purse-oyster Isognomon bicolor, the whiteleg shrimp Litopenaeus vannamei, the giant river prawn Macrobrachium rosenbergii, the Indo-Pacific swimming crab Charybdis hellerii and, the muzzled blenny Omobranchus punctatus. Ballast water (I. bicolor, C. hellerii, and O. punctatus) and aquaculture activities (L. vannamei and M. rosenbergii) in adjacent areas are the most likely vectors of introduction. All exotic species found have potential impact risks to the environment because they are able to compete against native species for resources (food and habitat). Isognomon bicolor share the same habitat and food items with the native bivalve species of mussels and barnacles. Litopenaeus vannamei share the same habitat and food items with the native penaeids such as the pinkspot shrimp Farfantepenaeus brasiliensis, the Southern brown shrimp Farfantepenaeus subtilis, and the Southern white shrimp Litopenaeus schmitti, and in the past few years L. vannamei was responsible for a viral epidemics in the cultivation tanks that could be transmitted to native penaeid shrimps. Charybdis hellerii is also able to cause impacts on the local fisheries as the species can decrease the populations of native portunid crabs which are commercialized in the studied region. Macrobrachium rosenbergii may be sharing natural resources with the Amazon River prawn Macrobrachium amazonicum. Omobranchus punctatus shares habit with the native redlip blenny

  7. Registros novos e adicionais de teleósteos marinhos na costa brasileira

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    Rodrigo Antunes Caires

    2008-01-01

    Calamus mu (Sparidae, a species formerly circumscribed to the region between Espírito Santo and São Paulo, and additional records of Bascanichthys paulensis (Ophichthidae, Nezumia aequalis (Macrouridae, Antigonia combatia (Caproidae and Notolycodes schmitti (Zoarcidae.

  8. Analysis of the characteristics of ten cartilaginous fishes mitochondrial genomes%10种软骨鱼线粒体基因组特征分析

    Institute of Scientific and Technical Information of China (English)

    申欣; 田美; 孟学平; 程汉良

    2011-01-01

    The basic characteristics of chondrichthyes mitochondrial genomes were fully revealed by comprehensive analysis of mitochondrial genomes in ten cartilaginous fishes.Mitochondrial genomes of cartilaginous fishes contain 37 standard metazoan genes and their gene order is identical.The Ka/Ks ratio of 13 mitochondrial protein-coding genes in the Carcharhiniformes and Rajiformes classes is much lower than 1 (0.019 1~0.156 4), indicating a strong purifying selection (negative selection).The phylogenetic trees based on mitochondrial genomes showed that the class Chondrichthyes is divided into two clades: the subclass Holocephali and the subclass Elasmobranchii.Inside the subclass Elasmobranchii, the order Rajiformes and the order Myliobatiformes were clustered as a clade, and the other five orders (Carcharhiniformes, Lamniformes, Orectolobiformes, Heterodontiformes, and Squaliformes) were clustered as another clade.The phylogenetic relationship is (((Carcharhiniformes + Lamniformes) + Orectolobiformes) + Heterodontiformes) +Squaliformes.The genetic variation analysis of main genes (13 protein coding genes and 2 ribosomal RNA genes) among cartilaginous fish species showed that nad5 and nad4 genes are ideal molecular markers and can be used as supplementary molecular markers to coxl gene,which can be used to analyze the genetic diversity among different groups and provide more basis for rational use of its biological resources.%综合分析了软骨鱼10个物种的线粒体基因组全序列,全面揭示软骨鱼线粒体基因组的基本特征、蛋白质编码基因和差异位点等.软骨鱼10个物种线粒体基因组均编码后生动物标准的37个基因,而且其基因排列完全相同.真鲨目和鳐形目线粒体基因组的13个蛋白质编码基因的Ka/Ks比值都远远低于1(0.019 1~0.156 4),显示出较强的纯化(负)选择.基于线粒体基因组构建的系统发育树结果显示,软骨鱼纲分为两支:全头亚纲和板鳃亚纲.在板

  9. Taxonomic distinctness of demersal fishes of the California current: moving beyond simple measures of diversity for marine ecosystem-based management.

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    Nick Tolimieri

    Full Text Available BACKGROUND: Large-scale patterns or trends in species diversity have long interested ecologists. The classic pattern is for diversity (e.g., species richness to decrease with increasing latitude. Taxonomic distinctness is a diversity measure based on the relatedness of the species within a sample. Here we examined patterns of taxonomic distinctness in relation to latitude (ca. 32-48 degrees N and depth (ca. 50-1220 m for demersal fishes on the continental shelf and slope of the US Pacific coast. METHODOLOGY/PRINCIPAL FINDINGS: Both average taxonomic distinctness (AvTD and variation in taxonomic distinctness (VarTD changed with latitude and depth. AvTD was highest at approximately 500 m and lowest at around 200 m bottom depth. Latitudinal trends in AvTD were somewhat weaker and were depth-specific. AvTD increased with latitude on the shelf (50-150 m but tended to decrease with latitude at deeper depths. Variation in taxonomic distinctness (VarTD was highest around 300 m. As with AvTD, latitudinal trends in VarTD were depth-specific. On the shelf (50-150 m, VarTD increased with latitude, while in deeper areas the patterns were more complex. Closer inspection of the data showed that the number and distribution of species within the class Chondrichthyes were the primary drivers of the overall patterns seen in AvTD and VarTD, while the relatedness and distribution of species in the order Scorpaeniformes appeared to cause the relatively low observed values of AvTD at around 200 m. CONCLUSIONS/SIGNIFICANCE: These trends contrast to some extent the patterns seen in earlier studies for species richness and evenness in demersal fishes along this coast and add to our understanding of diversity of the demersal fishes of the California Current.

  10. Feeding biomechanics and theoretical calculations of bite force in bull sharks (Carcharhinus leucas) during ontogeny.

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    Habegger, Maria L; Motta, Philip J; Huber, Daniel R; Dean, Mason N

    2012-12-01

    Evaluations of bite force, either measured directly or calculated theoretically, have been used to investigate the maximum feeding performance of a wide variety of vertebrates. However, bite force studies of fishes have focused primarily on small species due to the intractable nature of large apex predators. More massive muscles can generate higher forces and many of these fishes attain immense sizes; it is unclear how much of their biting performance is driven purely by dramatic ontogenetic increases in body size versus size-specific selection for enhanced feeding performance. In this study, we investigated biting performance and feeding biomechanics of immature and mature individuals from an ontogenetic series of an apex predator, the bull shark, Carcharhinus leucas (73-285cm total length). Theoretical bite force ranged from 36 to 2128N at the most anterior bite point, and 170 to 5914N at the most posterior bite point over the ontogenetic series. Scaling patterns differed among the two age groups investigated; immature bull shark bite force scaled with positive allometry, whereas adult bite force scaled isometrically. When the bite force of C. leucas was compared to those of 12 other cartilaginous fishes, bull sharks presented the highest mass-specific bite force, greater than that of the white shark or the great hammerhead shark. A phylogenetic independent contrast analysis of anatomical and dietary variables as determinants of bite force in these 13 species indicated that the evolution of large adult bite forces in cartilaginous fishes is linked predominantly to the evolution of large body size. Multiple regressions based on mass-specific standardized contrasts suggest that the evolution of high bite forces in Chondrichthyes is further correlated with hypertrophication of the jaw adductors, increased leverage for anterior biting, and widening of the head. Lastly, we discuss the ecological significance of positive allometry in bite force as a possible

  11. On the haptic nature of the active electric sense of fish.

    Science.gov (United States)

    Caputi, Angel A; Aguilera, Pedro A; Carolina Pereira, Ana; Rodríguez-Cattáneo, Alejo

    2013-11-06

    Electroreception is a sensory modality present in chondrichthyes, actinopterygii, amphibians, and mammalian monotremes. The study of this non-intuitive sensory modality has provided insights for better understanding of sensory systems in general and inspired the development of innovative artificial devices. Here we review evidence obtained from the analysis of electrosensory images, neurophysiological data from the recording of unitary activity in the electrosensory lobe, and psychophysical data from analysis of novelty responses provoked in well-defined stimulus conditions, which all confirm that active electroreception has a short range, and that the influence of exploratory movements on object identification is strong. In active electric images two components can be identified: a "global" image profile depending on the volume, shape and global impedance of an object and a "texture" component depending on its surface attributes. There is a short range of the active electric sense and the progressive "blurring" of object image with distance. Consequently, the lack of precision regarding object location, considered together, challenge the current view of this sense as serving long range electrolocation and the commonly used metaphor of "electric vision". In fact, the active electric sense shares more commonalities with human active touch than with teleceptive senses as vision or audition. Taking into account that other skin exteroceptors and proprioception may be congruently stimulated during fish exploratory movements we propose that electric, mechanoceptive and proprioceptive sensory modalities found in electric fish could be considered together as a single haptic sensory system. This article is part of a Special Issue entitled Neural Coding 2012. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Construction of a nurse shark (Ginglymostoma cirratum bacterial artificial chromosome (BAC library and a preliminary genome survey

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    Inoko Hidetoshi

    2006-05-01

    Full Text Available Abstract Background Sharks are members of the taxonomic class Chondrichthyes, the oldest living jawed vertebrates. Genomic studies of this group, in comparison to representative species in other vertebrate taxa, will allow us to theorize about the fundamental genetic, developmental, and functional characteristics in the common ancestor of all jawed vertebrates. Aims In order to obtain mapping and sequencing data for comparative genomics, we constructed a bacterial artificial chromosome (BAC library for the nurse shark, Ginglymostoma cirratum. Results The BAC library consists of 313,344 clones with an average insert size of 144 kb, covering ~4.5 × 1010 bp and thus providing an 11-fold coverage of the haploid genome. BAC end sequence analyses revealed, in addition to LINEs and SINEs commonly found in other animal and plant genomes, two new groups of nurse shark-specific repetitive elements, NSRE1 and NSRE2 that seem to be major components of the nurse shark genome. Screening the library with single-copy or multi-copy gene probes showed 6–28 primary positive clones per probe of which 50–90% were true positives, demonstrating that the BAC library is representative of the different regions of the nurse shark genome. Furthermore, some BAC clones contained multiple genes, making physical mapping feasible. Conclusion We have constructed a deep-coverage, high-quality, large insert, and publicly available BAC library for a cartilaginous fish. It will be very useful to the scientific community interested in shark genomic structure, comparative genomics, and functional studies. We found two new groups of repetitive elements specific to the nurse shark genome, which may contribute to the architecture and evolution of the nurse shark genome.

  13. First shark from the Late Devonian (Frasnian Gogo Formation, Western Australia sheds new light on the development of tessellated calcified cartilage.

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    John A Long

    Full Text Available Living gnathostomes (jawed vertebrates comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans and Osteichthyes (bony fishes including tetrapods. Most of the early chondrichthyan ('shark' record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group--prismatic calcified cartilage and pelvic claspers in males--being from the latest Devonian, c. 360 Mya. This paucity of information about early chondrichthyan anatomy is mainly due to their lack of endoskeletal bone and consequent low preservation potential.Here we present new data from the first well-preserved chondrichthyan fossil from the early Late Devonian (ca. 380-384 Mya Gogo Formation Lägerstatte of Western Australia. The specimen is the first Devonian shark body fossil to be acid-prepared, revealing the endoskeletal elements as three-dimensional undistorted units: Meckel's cartilages, nasal, ceratohyal, basibranchial and possible epibranchial cartilages, plus left and right scapulocoracoids, as well as teeth and scales. This unique specimen is assigned to Gogoselachus lynnbeazleyae n. gen. n. sp.The Meckel's cartilages show a jaw articulation surface dominated by an expansive cotylus, and a small mandibular knob, an unusual condition for chondrichthyans. The scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets, differing from the standard condition for early gnathostomes which have either one or three articulations. The tooth structure is intermediate between the 'primitive' ctenacanthiform and symmoriiform condition, and more derived forms with a euselachian-type base. Of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton, comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix

  14. Spatiotemporal variability of ifsh assemblage in the Shatt Al-Arab River, Iraq

    Institute of Scientific and Technical Information of China (English)

    Abdul-Razak M Mohamed; Saddek A Hussein; Laith F Lazem

    2015-01-01

    Objective:To study spatial and temporal variability of fish assemblage in the Shatt Al-Arab River. Methods: This study was conducted from December 2011 to November 2012. Water temperature, salinity, dissolved oxygen and transparency were measured from three sites in the river. Several fishing methods were adopted to collect fish including gill nets, cast net, electro-fishing and hook and lines. Associations between the distribution of fish species and the environmental variables were quantified by using canonical correspondence analysis. Results:The results showed that the fish assemblage consisted of 58 species representing 46 genera and 27 families belong to Osteichthyes except one (Carcharhinus leucas) relate to Chondrichthyes. Number of species increased in summer and autumn months and sharply decreased in winter. Tenualosa ilisha was the most abundant species comprising 27.4%of the catch, followed by Carassius auratus (23.7%) and Liza klunzingeri (10.6%). The dominance (D3) value for the main three abundant species was 61.7%. Nine species were caught for the first times from the river include eight marine. The overall values of diversity index ranged from 0.67 in March to 2.57 in October, richness index from 2.64 in January to 3.71 in September and evenness index from 0.22 in March to 0.73 in August. Conclusions:Spatially, the fish assemblages of Shatt Al-Arab River can be divided into three ecological fish guilds, namely, common species, seasonal species and occasional species.

  15. Determination Methods for the Exoskeletal Remains of Early Vertebrates

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    V. Karatajute-Talimaa

    1998-01-01

    üher Vertebraten (Astraspiden, Tesakoviaspiden, Heterostraken, Thelodontier, Mongolepiden, Chondrichthyer und Acanthodier, die im frühen Paläozoikum weit verbreitet sind, werden als Beispiele benutzt. doi:10.1002/mmng.19980010103

  16. A comparative study of the ocular skeleton of fossil and modern chondrichthyans.

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    Pilgrim, Brettney L; Franz-Odendaal, Tamara A

    2009-06-01

    Many vertebrates have an ocular skeleton composed of cartilage and/or bone situated within the sclera of the eye. In this study we investigated whether modern and fossil sharks have an ocular skeleton, and whether it is conserved in morphology. We describe the scleral skeletal elements of three species of modern sharks and compare them to those found in fossil sharks from the Cleveland Shale (360 Mya). We also compare the elements to contemporaneous arthrodires from the same deposit. Surprisingly, the morphology of the skeletal support of the eye was found to differ significantly between modern and fossil sharks. All three modern shark species examined (spiny dogfish shark Squalus acanthias, porbeagle shark Lamna nasus and blue shark Prionace glauca) have a continuous skeletal element that encapsulates much of the eyeball; however, the tissue composition is different in each species. Histological and morphological examination revealed scleral cartilage with distinct tesserae in parts of the sclera of the porbeagle and blue shark, and more diffuse calcification in the dogfish. Strengthening of the scleral cartilage by means of tesserae has not been reported previously in the shark eye. In striking contrast, the ocular skeleton of fossil sharks comprises a series of individual elements that are arranged in a ring, similar to the arrangement in modern and fossil reptiles. Fossil arthrodires also have a multi-unit sclerotic ring but these are composed of fewer elements than in fossil sharks. The morphology of these elements has implications for the behaviour and visual capabilities of sharks that lived during the Devonian Period. This is the first time that such a dramatic variation in the morphology of scleral skeletal elements has been observed in a single lineage (Chondrichthyes), making this lineage important for broadening our understanding of the evolution of these elements within jawed vertebrates.

  17. Early development of rostrum saw-teeth in a fossil ray tests classical theories of the evolution of vertebrate dentitions.

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    Smith, Moya Meredith; Riley, Alex; Fraser, Gareth J; Underwood, Charlie; Welten, Monique; Kriwet, Jürgen; Pfaff, Cathrin; Johanson, Zerina

    2015-10-07

    In classical theory, teeth of vertebrate dentitions evolved from co-option of external skin denticles into the oral cavity. This hypothesis predicts that ordered tooth arrangement and regulated replacement in the oral dentition were also derived from skin denticles. The fossil batoid ray Schizorhiza stromeri (Chondrichthyes; Cretaceous) provides a test of this theory. Schizorhiza preserves an extended cartilaginous rostrum with closely spaced, alternating saw-teeth, different from sawfish and sawsharks today. Multiple replacement teeth reveal unique new data from micro-CT scanning, showing how the 'cone-in-cone' series of ordered saw-teeth sets arrange themselves developmentally, to become enclosed by the roots of pre-existing saw-teeth. At the rostrum tip, newly developing saw-teeth are present, as mineralized crown tips within a vascular, cartilaginous furrow; these reorient via two 90° rotations then relocate laterally between previously formed roots. Saw-tooth replacement slows mid-rostrum where fewer saw-teeth are regenerated. These exceptional developmental data reveal regulated order for serial self-renewal, maintaining the saw edge with ever-increasing saw-tooth size. This mimics tooth replacement in chondrichthyans, but differs in the crown reorientation and their enclosure directly between roots of predecessor saw-teeth. Schizorhiza saw-tooth development is decoupled from the jaw teeth and their replacement, dependent on a dental lamina. This highly specialized rostral saw, derived from diversification of skin denticles, is distinct from the dentition and demonstrates the potential developmental plasticity of skin denticles. © 2015 The Authors.

  18. Temporal dynamics of demersal chondrichthyan species in the central western Mediterranean

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    Antonello Mulas

    2015-11-01

    Full Text Available The rapid expansion of fisheries and globalized trade are emerging as the principal drivers of coastal and ocean threat. Considering the important role of Chondrichthyes as predators at the top of food chain in marine ecosystems, knowledge on their biology remains scarce in the Mediterranean. In this regard, our objective is to give information on their spatial distribution, abundance and population structure. Data were collected for 25 demersal species, including batoid species, sharks and holocephalans from 1994 to 2013 during scientific bottom trawl surveys (MEDITS project carried out around the Sardinian seas. The total frequency of occurrence (f%, the Biomass Index (BI, kg/km2, and the Density Index (DI, N/km2 were estimated for the continental shelf (10-200 m, slope (200-800 m, and overall (10-800 m depth strata. Size trends were also calculated for the most abundant species considering all depth strata. The correlation among MEDITS figures (f%, BI, DI, size structure and years were assessed by species computing the Pearson linear coefficient. From f% and abundance indexes investigation, only the small spotted catshark Scyliorhinus canicula and the thornback ray Raja clavata were ubiquitous in all strata investigated, instead, all the other species showed a preferential distribution for the shelf or the slope. In general, the temporal trends of BI and DI were stable or positive for both macro-strata, except for the longnose spurdog Squalus blainville which seemed to show a statistically significant decreasing trend. All analyzed species displayed temporal stable trends in size structure analysis, apart from Raja brachyura and Dipturus oxyrinchus that showed a statistically significant increase. Despite the time series analysis revealed stable or positive trends, it appears clear the need of urgent management measures to protect the demersal chondrichthyan species extending the monitoring over time and implementing the data collected by

  19. Spatiotemporal variability of fish assemblage in the Shatt Al-Arab River, Iraq

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    Abdul-Razak M. Mohamed

    2015-01-01

    Full Text Available Objective: To study spatial and temporal variability of fish assemblage in the Shatt Al-Arab River. Methods: This study was conducted from December 2011 to November 2012. Water temperature, salinity, dissolved oxygen and transparency were measured from three sites in the river. Several fishing methods were adopted to collect fish including gill nets, cast net, electro-fishing and hook and lines. Associations between the distribution of fish species and the environmental variables were quantified by using canonical correspondence analysis. Results: The results showed that the fish assemblage consisted of 58 species representing 46 genera and 27 families belong to Osteichthyes except one (Carcharhinus leucas relate to Chondrichthyes. Number of species increased in summer and autumn months and sharply decreased in winter. Tenualosa ilisha was the most abundant species comprising 27.4% of the catch, followed by Carassius auratus (23.7% and Liza klunzingeri (10.6%. The dominance (D3 value for the main three abundant species was 61.7%. Nine species were caught for the first times from the river include eight marine. The overall values of diversity index ranged from 0.67 in March to 2.57 in October, richness index from 2.64 in January to 3.71 in September and evenness index from 0.22 in March to 0.73 in August. Conclusions: Spatially, the fish assemblages of Shatt Al-Arab River can be divided into three ecological fish guilds, namely, common species, seasonal species and occasional species.

  20. Forelimb-hindlimb developmental timing changes across tetrapod phylogeny

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    Selwood Lynne

    2007-10-01

    Full Text Available Abstract Background Tetrapods exhibit great diversity in limb structures among species and also between forelimbs and hindlimbs within species, diversity which frequently correlates with locomotor modes and life history. We aim to examine the potential relation of changes in developmental timing (heterochrony to the origin of limb morphological diversity in an explicit comparative and quantitative framework. In particular, we studied the relative time sequence of development of the forelimbs versus the hindlimbs in 138 embryos of 14 tetrapod species spanning a diverse taxonomic, ecomorphological and life-history breadth. Whole-mounts and histological sections were used to code the appearance of 10 developmental events comprising landmarks of development from the early bud stage to late chondrogenesis in the forelimb and the corresponding serial homologues in the hindlimb. Results An overall pattern of change across tetrapods can be discerned and appears to be relatively clade-specific. In the primitive condition, as seen in Chondrichthyes and Osteichthyes, the forelimb/pectoral fin develops earlier than the hindlimb/pelvic fin. This pattern is either retained or re-evolved in eulipotyphlan insectivores (= shrews, moles, hedgehogs, and solenodons and taken to its extreme in marsupials. Although exceptions are known, the two anurans we examined reversed the pattern and displayed a significant advance in hindlimb development. All other species examined, including a bat with its greatly enlarged forelimbs modified as wings in the adult, showed near synchrony in the development of the fore and hindlimbs. Conclusion Major heterochronic changes in early limb development and chondrogenesis were absent within major clades except Lissamphibia, and their presence across vertebrate phylogeny are not easily correlated with adaptive phenomena related to morphological differences in the adult fore- and hindlimbs. The apparently conservative nature of this

  1. Registro Fossílifero das Raias (Chondrichtes-Batomorphi em Bacias Sedimentares Brasileiras.

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    Paloma Tâmega da Silva Abreu Moreira

    2007-07-01

    Full Text Available A classe dos Chondrichthyes é representadapelos Elasmobranchii (tubarões e raias e Holocephali(quimeras. A presença de fósseis de raias em baciassedimentares brasileiras é conhecida desde o séculoXIX, sendo representadas atualmente por seisfamílias. São estruturas de difícil preservação, sendo,portanto raras no registro fossilífero. A grande maioriados registros é de espinhos e dentes, mas ocorrênciasextraordinárias de exemplares quase completos deraias e tubarão foram encontradas na Chapada doAraripe, nordeste do Brasil. A primeira espécie foidescrita da bacia de Pernambuco e posteriormentemais três espécies foram assinaladas nas baciasde Sergipe, Pernambuco e Araripe. O restante domaterial é conhecido apenas em nível de gêneroou família. Com base na literatura, foi realizadoum inventário destas ocorrências, pertencentes aoacervo de várias instituições de pesquisa, permitindorecuperar e atualizar as informações, sistematizandoas ocorrências e o material depositado nas diversascoleções. No Museu de Ciências da Terra/DNPM,Rio de Janeiro foram encontrados 69 dentes isolados,provenientes das bacias de Pernambuco, Sergipe ePirabas e um exemplar quase completo da bacia doAraripe. Constam sete placas dentárias, 118 dentese quatro espinhos caudais provenientes das baciasde São Luís, Pirabas, Acre, Pernambuco, Sergipee Pelotas. Dentre os gêneros estudados, os maisrepresentativos são: Myliobatis sp. com 60 dentes eRhombodus binkhorsti com 52 dentes.

  2. Reproductive endocrinology in chondrichthyans: the present and the future.

    Science.gov (United States)

    Awruch, C A

    2013-10-01

    The class Chondrichthyes, that includes Elasmobranchii and Holocephali, is a diverse group of fish occupying a key position at the base of vertebrate evolution. Their evolutionary success is greatly attributed to their wide range of reproductive strategies controlled by different endocrine mechanics. As in other vertebrates, hormonal control of reproduction in chondrichthyans is mediated by the neuropeptide gonadotropin-releasing hormone (GnRH) that regulates the brain control of gonadal activity via a hypothalamus-pituitary-gonadal (HPG) axis. Chondrichthyans lack of a direct vascular supply from the hypothalamus to the zone of the pituitary where the gonadotropic activity resides, thus transport between these two zones likely occurs via the general circulation. In the brain of elasmobranchs, two groups of GnRH, GnRH-I and GnRH-II were identified, and the presence of two immunoreactive gonadotropins similar to the luteinising (LH) and follicle stimulating (FSH) hormones was identified in the pituitary. In holocephalans, only GnRH-II has been confirmed, and while gonadotropin activity has been found in the buccal pituitary lobe, the presence of gonadotropin receptors in the gonads remains unknowns. The diversity of reproductive strategies display by chondrichthyans makes it difficult to generalize the control of gametogenesis and steroidogenesis; however, some general patterns emerge. In both sexes, androgens and estrogens are the main steroids during gonadal growth; while progestins have maturational activity. Androgens also form the precursors for estrogen steroid production. Estrogens stimulate the hepatic synthesis of yolk and stimulate the development of different part of the reproductive tract in females. The role of other gonadal steroids may play in chondrichthyan reproduction remains largely unknown. Future work should concentrate in filling the gaps into the current knowledge of the HPG axis regulation, and the use of reproductive endocrinology as a non

  3. Devonian (Emsian-Eifelian) fish from the Lower Bokkeveld Group (Ceres Subgroup), South Africa

    Science.gov (United States)

    Anderson, M. E.; Almond, J. E.; Evans, F. J.; Long, J. A.

    1999-07-01

    Four major groups of fish are represented by fragmentary remains from South Africa's Lower Bokkeveld Group of Early to Middle Devonian age: the Acanthodii, Chondrichthyes, Placodermi and Osteichthyes. These represent the oldest known occurrences of these groups in southern Africa, as well as an important addition to the very meagre record of earlier Devonian fish from the Malvinokaffric Province of southwestern Gondwana. Bokkeveld fish material comes from the Gydo (Late Emsian) and Tra Tra (Middle Eifelian) Formations of the Western Cape and Eastern Cape Provinces. The cosmopolitan marine acanthodian Machæracanthus is represented only by isolated fin spines which may belong to two different species on the basis of their external ornamentation, cross-sectional outline and internal histology. The elasmobranchs are represented by four elements: (1) a flattened chondrocranium which bears affinity to the Late Devonian-Carboniferous symmoriid (protacrodont) 'cladodont' sharks. It is probably the earliest known (Emsian) shark chondrocranium; (2) an isolated, primitive scapulocoracoid with a very short coracoidal ridge; (3) ankylosed and isolated radials, interpreted as parts of pterygial plates of a paired fin of an unknown chondrichthyan bearing affinity to the Middle Devonian Zamponiopteron from Bolivia; and (4) isolated barlike structures, perhaps gill arch or a jaw elements, thought to be from the same taxon as (3). The placoderms are represented by an incomplete trunk armour and fragmentary, finely ornamented plates of a primitive antiarch. The Osteichthyes are represented by a single large scale of an unidentified dipnoan from the Eifelian of the Cedarberg range, as well as a probable sarcopterygian dermal plate from the Emsian of the Prince Albert area. These are among the earliest sarcopterygian remains recorded from the Malvinokaffric Province.

  4. Aryl hydrocarbon receptor function in early vertebrates:Inducibility of cytochrome P450 1A in agnathan and elasmobranch fish

    Science.gov (United States)

    Hahn, Mark E.; Woodin, Bruce R.; Stegeman, John J.; Tillitt, Donald E.

    1998-01-01

    The mammalian aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that controls the expression of cytochrome P450 1A (CYP1A) genes in response to halogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The natural ligand and normal physiologic function of this protein are as yet unknown. One approach to understanding AHR function and significance is to determine the evolutionary history of this receptor and of processes such as CYP1A induction that are controlled by the AHR in mammals. In these studies, AHR function was evaluated in representative cartilaginous fish (little skate, Raja erinacea) and jawless fish (sea lamprey, Petromyzon marinus and Atlantic hagfish, Myxine glutinosa), using CYP1A induction as a model AHR-dependent response. Treatment of skate with β-naphthoflavone (BNF) caused an 8-fold increase in hepatic ethoxyresorufin O-deethylase (EROD) activity as well as a 37-fold increase in the content of immunodetectable CYP1A protein. Evidence of CYP1A inducibility was also obtained for another cartilaginous fish, the smooth dogfish Mustelus canis. In contrast, hepatic EROD activity was not detected in untreated lamprey nor in lamprey treated with 3,3′,4,4′-tetrachlorobiphenyl (TCB), a potent AHR agonist in teleosts. A possible CYP1A homolog was detected in lamprey hepatic microsomes by one of three antibodies to teleost CYP1A, but expression of this protein was not altered by TCB treatment. CYP1A protein and catalytic activity were measurable in hagfish, but neither was induced after treatment with TCB. These results suggest that the AHR-CYP1A signal transduction pathway is highly conserved in gnathostomes, but that there may be fundamental differences in AHR signaling or AHR-CYP1A coupling in agnathan fish. Agnathan fish such as hagfish and lamprey may be interesting model species for examining possible ancestral AHR functions not related to CYP1A regulation.

  5. Cranial nerves of the coelacanth, Latimeria chalumnae [Osteichthyes: Sarcopterygii: Actinistia], and comparisons with other craniata.

    Science.gov (United States)

    Northcutt, R G; Bemis, W E

    1993-01-01

    We reconstructed the cranial nerves of a serially sectioned prenatal coelacanth, Latimeria chalumnae. This allowed us to correct several mistakes in the literature and to make broad phylogenetic comparisons with other craniates. The genera surveyed in our phylogenetic analysis were Eptatretus, Myxine, Petromyzon, Lampetra, Chimaera, Hydrolagus, Squalus, Mustelus, Polypterus, Acipenser, Lepisosteus, Amia, Neoceratodus, Protopterus, Lepidosiren, Latimeria and Ambystoma. Cladistic analysis of our data shows that Latimeria shares with Ambystoma two characters of the cranial nerves. Our chief findings are: 1) Latimeria possesses an external nasal papilla and pedunculated olfactory bulbs but lacks a discrete terminal nerve. In other respects its olfactory system resembles the plesiomorphic pattern for craniates. 2) The optic nerve is plicated, a character found in many but not all gnathostomes. Latimeria retains an interdigitated partial decussation of the optic nerves, a character found in all craniates surveyed. 3) The oculomotor nerve supplies the same extrinsic eye muscles as in lampreys and gnathostomes. As in gnathostomes generally, Latimeria has a ciliary ganglion but its cells are located intracranially in the root of the oculomotor nerve, and their processes reach the eye via oculomotor and profundal rami. 4) The trochlear nerve supplies the superior oblique muscle as in all craniates that have not secondarily reduced the eye and its extrinsic musculature. 5) The profundal ganglion and ramus are entirely separate from the trigeminal system, with no exchange of fibers. This character has an interesting phylogenetic distribution: in hagfishes, lampreys, lungfishes and tetrapods, the profundal and trigeminal ganglia are fused, whereas in other taxa surveyed the ganglia are separate. The principal tissues innervated by the profundal nerve are the membranous walls of the tubes of the rostral organ. 6) As in lampreys and gnathostomes, the trigeminal nerve has

  6. Composition of glycosaminoglycans in elasmobranchs including several deep-sea sharks: identification of chondroitin/dermatan sulfate from the dried fins of Isurus oxyrinchus and Prionace glauca.

    Science.gov (United States)

    Higashi, Kyohei; Takeuchi, Yoshiki; Mukuno, Ann; Tomitori, Hideyuki; Miya, Masaki; Linhardt, Robert J; Toida, Toshihiko

    2015-01-01

    Shark fin, used as a food, is a rich source of glycosaminoglyans (GAGs), acidic polysaccharides having important biological activities, suggesting their nutraceutical and pharmaceutical application. A comprehensive survey of GAGs derived from the fin was performed on 11 elasmobranchs, including several deep sea sharks. Chondroitin sulfate (CS) and hyaluronic acid (HA) were found in Isurus oxyrinchus, Prionace glauca, Scyliorhinus torazame, Deania calcea, Chlamydoselachus anguineus, Mitsukurina owatoni, Mustelus griseus and Dasyatis akajei, respectively. CS was only found from Chimaera phantasma, Dalatias licha, and Odontaspis ferox, respectively. Characteristic disaccharide units of most of the CS were comprised of C- and D-type units. Interestingly, substantial amount of CS/dermatan sulfate (DS) was found in the dried fin (without skin and cartilage) of Isurus oxyrinchus and Prionace glauca. 1H-NMR analysis showed that the composition of glucuronic acid (GlcA) and iduronic acid (IdoA) in shark CS/DS was 41.2% and 58.8% (Isurus oxyrinchus), 36.1% and 63.9% (Prionace glauca), respectively. Furthermore, a substantial proportion of this CS/DS consisted of E-, B- and D-type units. Shark CS/DS stimulated neurite outgrowth of hippocampal neurons at a similar level as DS derived from invertebrate species. Midkine and pleiotrophin interact strongly with CS/DS from Isurus oxyrinchus and Prionace glauca, affording Kd values of 1.07 nM, 6.25 nM and 1.70 nM, 1.88 nM, respectively. These results strongly suggest that the IdoA-rich domain of CS/DS is required for neurite outgrowth activity. A detailed examination of oligosaccharide residues, produced by chondroitinase ACII digestion, suggested that the IdoA and B-type units as well as A- and C-type units were found in clusters in shark CS/DS. In addition, it was discovered that the contents of B-type units in these IdoA-rich domain increased in a length dependent manner, while C- and D-type units were located particularly in the

  7. Composition of glycosaminoglycans in elasmobranchs including several deep-sea sharks: identification of chondroitin/dermatan sulfate from the dried fins of Isurus oxyrinchus and Prionace glauca.

    Directory of Open Access Journals (Sweden)

    Kyohei Higashi

    Full Text Available Shark fin, used as a food, is a rich source of glycosaminoglyans (GAGs, acidic polysaccharides having important biological activities, suggesting their nutraceutical and pharmaceutical application. A comprehensive survey of GAGs derived from the fin was performed on 11 elasmobranchs, including several deep sea sharks. Chondroitin sulfate (CS and hyaluronic acid (HA were found in Isurus oxyrinchus, Prionace glauca, Scyliorhinus torazame, Deania calcea, Chlamydoselachus anguineus, Mitsukurina owatoni, Mustelus griseus and Dasyatis akajei, respectively. CS was only found from Chimaera phantasma, Dalatias licha, and Odontaspis ferox, respectively. Characteristic disaccharide units of most of the CS were comprised of C- and D-type units. Interestingly, substantial amount of CS/dermatan sulfate (DS was found in the dried fin (without skin and cartilage of Isurus oxyrinchus and Prionace glauca. 1H-NMR analysis showed that the composition of glucuronic acid (GlcA and iduronic acid (IdoA in shark CS/DS was 41.2% and 58.8% (Isurus oxyrinchus, 36.1% and 63.9% (Prionace glauca, respectively. Furthermore, a substantial proportion of this CS/DS consisted of E-, B- and D-type units. Shark CS/DS stimulated neurite outgrowth of hippocampal neurons at a similar level as DS derived from invertebrate species. Midkine and pleiotrophin interact strongly with CS/DS from Isurus oxyrinchus and Prionace glauca, affording Kd values of 1.07 nM, 6.25 nM and 1.70 nM, 1.88 nM, respectively. These results strongly suggest that the IdoA-rich domain of CS/DS is required for neurite outgrowth activity. A detailed examination of oligosaccharide residues, produced by chondroitinase ACII digestion, suggested that the IdoA and B-type units as well as A- and C-type units were found in clusters in shark CS/DS. In addition, it was discovered that the contents of B-type units in these IdoA-rich domain increased in a length dependent manner, while C- and D-type units were located

  8. Global versus local causes and health implications of high mercury concentrations in sharks from the east coast of South Africa

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, Melissa A., E-mail: melissa.mckinney@uconn.edu [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Dean, Kylie; Hussey, Nigel E. [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Cliff, Geremy; Wintner, Sabine P. [KwaZulu-Natal Sharks Board, Umhlanga Rocks 4320 (South Africa); Biomedical Resource Unit, University of KwaZulu-Natal, Durban 4000 (South Africa); Dudley, Sheldon F.J. [KwaZulu-Natal Sharks Board, Umhlanga Rocks 4320 (South Africa); Department of Agriculture, Forestry and Fisheries, Cape Town 8012 (South Africa); Zungu, M. Philip [Department of Agriculture, Forestry and Fisheries, Cape Town 8012 (South Africa); Fisk, Aaron T. [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

    2016-01-15

    Conservation concern regarding the overharvest of global shark populations for meat and fin consumption largely surrounds documented deleterious ecosystem effects, but may be further supported by improved knowledge of possibly high levels in their edible tissues (particularly meat) of the neurotoxin, methylmercury (CH{sub 3}Hg). For many regions, however, little data exist on shark tissue Hg concentrations, and reasons for Hg variation within and among species or across regions are poorly understood. We quantified total Hg (THg) in 17 shark species (total n = 283) from the east coast of South Africa, a top Hg emitter globally. Concentrations varied from means of around 0.1 mg kg{sup −1} dry weight (dw) THg in hardnose smoothhound (Mustelus mosis) and whale (Rhincodon typus) sharks to means of over 10 mg kg{sup −1} dw in shortfin mako (Isurus oxyrinchus), scalloped hammerhead (Sphyrna lewini), white (Carcharodon carcharias) and ragged-tooth (Carcharias taurus) sharks. These sharks had higher THg levels than conspecifics sampled from coastal waters of the North Atlantic and North, mid-, and South Pacific, and although sampling year and shark size may play a confounding role, this result suggests the potential importance of elevated local emissions. Values of THg showed strong, species-specific correlations with length, and nearly half the remaining variation was explained by trophic position (using nitrogen stable isotopes, δ{sup 15}N), whereas measures of foraging habitat (using carbon stable isotopes, δ{sup 13}C) were not significant. Mercury concentrations were above the regulatory guidelines for fish health effects and safe human consumption for 88% and 70% of species, respectively, suggesting on-going cause for concern for shark health, and human consumers of shark meat. - Highlights: • Hg concentrations in 17 shark species from South Africa's east coast were measured. • Higher values relative to other regions suggested the importance of local

  9. Caracterização da pesca artesanal no complexo estuarino-lagunar de Cananéia-Iguape, Estado de São Paulo, Brasil (1995-1996 Amateur fishery in the estuary-lagoon complex of Cananéia-Iguape, state of São Paulo, Brazil (1995-1996

    Directory of Open Access Journals (Sweden)

    Jocemar Tomasino Mendonça

    2001-05-01

    , currently in operation, is motor-powered. The activity is, however, important to the region and contributes with 10 to 32% of total landing in Cananéia. The local amateur fishery is divided into two main groups: the near-shore fishery and the estuarine fishery. The former mainly exploits the Atlantic seabob (Xiphopenaeus kroyeri, the white shrimp (Litopenaeus schmitti. Fishermen fish with gillnet or long line in a typical small boat bottom trawl called as “bateira”. The fishing gear and techniques of the local estuarine fishery include the fence trap, the gillnet, and the floating and vertical long line. A typical small drift beam trawl net, locally known as “gerival”, is also used to catch juvenile shrimp Farfantepenaeus paulensis and F. brasiliensis, highly valuable bait for recreational fishing. The fence trap is the main fishing gear and more than 90 traps were set inside the estuary, where the target species is mullet (Mugil platanus, although many other species are also important catch items, e.g. Mugil curema, snook (Centropomus spp., whitemouth croaker (Micropogonias furnieri, king weakfish (Macrodon ancylodon and mojarras (Diapterus rhombeus. The production of Atlantic seabob, the most important species of Cananéia’s amateur fishery, fluctuated from year to year. The amateur fishery landings of Atlantic seabob were 34 t. in 1995 and 12 t. in 1996

  10. The invasion of five alien species in the Delta do Parnaíba Environmental Protection Area, Northeastern Brazil

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    Daniel Loebmann

    2010-09-01

    Full Text Available Marine biological invasions have been regarded as one of the major causes of native biodiversity loss, with shipping and aquaculture being the leading contributors for the introductions of alien species in aquatic ecosystems. In the present study, five aquatic alien species (one mollusk, three crustaceans and one fish species were detected during dives, shore searches and from the fisheries on the coast of the Delta do Parnaíba Environmental Protection Area, in the States of Piauí and Maranhão, Northeastern Brazil. The species were the bicolor purse-oyster Isognomon bicolor, the whiteleg shrimp Litopenaeus vannamei, the giant river prawn Macrobrachium rosenbergii, the Indo-Pacific swimming crab Charybdis hellerii and, the muzzled blenny Omobranchus punctatus. Ballast water (I. bicolor, C. hellerii, and O. punctatus and aquaculture activities (L. vannamei and M. rosenbergii in adjacent areas are the most likely vectors of introduction. All exotic species found have potential impact risks to the environment because they are able to compete against native species for resources (food and habitat. Isognomon bicolor share the same habitat and food items with the native bivalve species of mussels and barnacles. Litopenaeus vannamei share the same habitat and food items with the native penaeids such as the pinkspot shrimp Farfantepenaeus brasiliensis, the Southern brown shrimp Farfantepenaeus subtilis, and the Southern white shrimp Litopenaeus schmitti, and in the past few years L. vannamei was responsible for a viral epidemics in the cultivation tanks that could be transmitted to native penaeid shrimps. Charybdis hellerii is also able to cause impacts on the local fisheries as the species can decrease the populations of native portunid crabs which are commercialized in the studied region. Macrobrachium rosenbergii may be sharing natural resources with the Amazon River prawn Macrobrachium amazonicum. Omobranchus punctatus shares habit with the native

  11. The neuroecology of cartilaginous fishes: sensory strategies for survival.

    Science.gov (United States)

    Collin, Shaun P

    2012-01-01

    As apex predators, chondrichthyans, or cartilaginous fishes, hold an important position within a range of aquatic ecosystems and influence the balance between species' abundance and biodiversity. Having been in existence for over 400 million years and representing the earliest stages of the evolution of jawed vertebrates, this group also covers a diverse range of eco-morphotypes, occupying both marine and freshwater habitats. The class Chondrichthyes is divided into two subclasses: the Elasmobranchii (sharks, skates, and rays) and the Holocephali (elephant sharks and chimaeras). However, many of their life history traits, such as low fecundity, the production of small numbers of highly precocious young, slow growth rates, and late maturity, make them highly susceptible to human exploitation. To mitigate the negative effects of human impacts, it is important that we understand the sensory strategies that elasmobranchs use for navigating within their environment, forming reproductive aggregations, feeding, and even communicating. One approach to investigate the sensory bases of their behavior is to examine the peripheral sense organs mediating vision, olfaction, gustation, lateral line, electroreception, and audition in a large range of species in order to identify specific adaptations, the range of sensitivity thresholds, and the compromise between sensory spatial resolution and sensitivity. In addition, we can quantitatively assess the convergence of sensory input to the central nervous system and the relative importance of different sensory modalities. Using a comparative approach and often a combination of anatomical, electrophysiological, and molecular techniques, significant variation has been identified in the spatial and chromatic sampling of the photoreceptors in the eye, the surface area and the number of olfactory lamellae within the nasal cavity, the level of gustatory sampling within the oral cavity, the type and innervation of neuromasts of the lateral

  12. Fish genomes provide novel insights into the evolution of vertebrate secretin receptors and their ligand.

    Science.gov (United States)

    Cardoso, João C R; Félix, Rute C; Trindade, Marlene; Power, Deborah M

    2014-12-01

    The secretin receptor (SCTR) is a member of Class 2 subfamily B1 GPCRs and part of the PAC1/VPAC receptor subfamily. This receptor has long been known in mammals but has only recently been identified in other vertebrates including teleosts, from which it was previously considered to be absent. The ligand for SCTR in mammals is secretin (SCT), an important gastrointestinal peptide, which in teleosts has not yet been isolated, or the gene identified. This study revises the evolutionary model previously proposed for the secretin-GPCRs in metazoan by analysing in detail the fishes, the most successful of the extant vertebrates. All the Actinopterygii genomes analysed and the Chondrichthyes and Sarcopterygii fish possess a SCTR gene that shares conserved sequence, structure and synteny with the tetrapod homologue. Phylogenetic clustering and gene environment comparisons revealed that fish and tetrapod SCTR shared a common origin and diverged early from the PAC1/VPAC subfamily group. In teleosts SCTR duplicated as a result of the fish specific whole genome duplication but in all the teleost genomes analysed, with the exception of tilapia (Oreochromis niloticus), one of the duplicates was lost. The function of SCTR in teleosts is unknown but quantitative PCR revealed that in both sea bass (Dicentrarchus labrax) and tilapia (Oreochromis mossambicus) transcript abundance is high in the gastrointestinal tract suggesting it may intervene in similar processes to those in mammals. In contrast, no gene encoding the ligand SCT was identified in the ray-finned fishes (Actinopterygii) although it was present in the coelacanth (lobe finned fish, Sarcopterygii) and in the elephant shark (holocephalian). The genes in linkage with SCT in tetrapods and coelacanth were also identified in ray-finned fishes supporting the idea that it was lost from their genome. At present SCTR remains an orphan receptor in ray-finned fishes and it will be of interest in the future to establish why SCT was

  13. The phylogenetics of Anguillicolidae (Nematoda: Anguillicoloidea, swimbladder parasites of eels

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    Laetsch Dominik R

    2012-05-01

    Full Text Available Abstract Background Anguillicolidae Yamaguti, 1935 is a family of parasitic nematode infecting fresh-water eels of the genus Anguilla, comprising five species in the genera Anguillicola and Anguillicoloides. Anguillicoloides crassus is of particular importance, as it has recently spread from its endemic range in the Eastern Pacific to Europe and North America, where it poses a significant threat to new, naïve hosts such as the economic important eel species Anguilla anguilla and Anguilla rostrata. The Anguillicolidae are therefore all potentially invasive taxa, but the relationships of the described species remain unclear. Anguillicolidae is part of Spirurina, a diverse clade made up of only animal parasites, but placement of the family within Spirurina is based on limited data. Results We generated an extensive DNA sequence dataset from three loci (the 5' one-third of the nuclear small subunit ribosomal RNA, the D2-D3 region of the nuclear large subunit ribosomal RNA and the 5' half of the mitochondrial cytochrome c oxidase I gene for the five species of Anguillicolidae and used this to investigate specific and generic boundaries within the family, and the relationship of Anguillicolidae to other spirurine nematodes. Neither nuclear nor mitochondrial sequences supported monophyly of Anguillicoloides. Genetic diversity within the African species Anguillicoloides papernai was suggestive of cryptic taxa, as was the finding of distinct lineages of Anguillicoloides novaezelandiae in New Zealand and Tasmania. Phylogenetic analysis of the Spirurina grouped the Anguillicolidae together with members of the Gnathostomatidae and Seuratidae. Conclusions The Anguillicolidae is part of a complex radiation of parasitic nematodes of vertebrates with wide host diversity (chondrichthyes, teleosts, squamates and mammals, most closely related to other marine vertebrate parasites that also have complex life cycles. Molecular analyses do not support the recent

  14. Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution.

    Science.gov (United States)

    Romano, Carlo; Koot, Martha B; Kogan, Ilja; Brayard, Arnaud; Minikh, Alla V; Brinkmann, Winand; Bucher, Hugo; Kriwet, Jürgen

    2016-02-01

    significant reduction in osteichthyan body size. Neopterygii, the clade that encompasses the vast majority of extant fishes, underwent another diversification phase in the Late Triassic. The Triassic radiation of Osteichthyes, predominantly of Actinopterygii, which only occurred after severe extinctions among Chondrichthyes during the Middle-Late Permian, resulted in a profound change within global fish communities, from chondrichthyan-rich faunas of the Permo-Carboniferous to typical Mesozoic and Cenozoic associations dominated by actinopterygians. This turnover was not sudden but followed a stepwise pattern, with leaps during extinction events.

  15. Structure and function of the horn shark (Heterodontus francisci) cranium through ontogeny: development of a hard prey specialist.

    Science.gov (United States)

    Summers, Adam P; Ketcham, Richard A; Rowe, Timothy

    2004-04-01

    The horn sharks (Heterodontidae: Chondrichthyes) represent one of four independent evolutions of durophagy in the cartilaginous fishes. We used high-resolution computed tomography (CT scanning) to visualize and quantify the mineralized tissue of an ontogenetic series of horn sharks. CT scanning of neonatal through adult California horn sharks (Heterodontus francisci) confirmed that this technique is effective for examining mineralized tissue in even small (<10 mm) specimens. The jaw joint is among the first areas to become mineralized and is the most heavily mineralized area in the cranium of a neonatal horn shark. The hyoid is also well mineralized, although the poorly mineralized molariform teeth indicate that the neonatal animal may be a suction feeder on softer prey. The symphysis of the jaws never mineralizes, in sharp contrast to the condition in the hard prey-crushing stingrays. Digitally reslicing the CT scans along the jaws allowed measurement of the second moment of area (Ina). Assuming that the jaws are made of the same material at all ages, Ina is an indicator of the flexural stiffness of the jaws. In all sizes of shark the lower jaws were stiffer than the upper and the stiffness increased in the area of the molariform teeth. The central region of the jaws, where the rami meet, support cuspidate grasping teeth and has the lowest Ina. The spotted eagle ray (Aetobatus narinari), a hard prey-crushing stingray, shows a different pattern of flexural stiffness, with the peak at the central part of the jaws where the prey is reduced between flattened tooth plates. Although the eagle ray jaws have a higher Ina than the horn shark, they are also far more heavily mineralized. When the relative amounts of mineralization are taken into account, horn sharks do better with what mineral they have than does the eagle ray. With a tight jaw joint and loose mandibular symphysis, as well as nearly opposite patterns of stiffness in the jaws, it is clear that two of the

  16. A standard system to study vertebrate embryos.

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    Ingmar Werneburg

    also for other vertebrate groups not examined here, such as Chondrichthyes or Actinopterygii. An online database to type in developmental events for different stages and species could be a basis for further studies in comparative embryology. By documenting developmental events with the standard code, sequence heterochrony studies (i.e. Parsimov and studies on variability can use this broad comparative data set.

  17. Primera ictiofauna marina del Cretácico Superior (Formación Jaguel, Maastrichtiano de la provincia de Río Negro, Argentina First marine ichthyofauna from the Upper Cretaceous (Jaguel Formation; Maastrichtian from Río Negro province, Argentina

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    Sergio Bogan

    2010-01-01

    Full Text Available Se describe un conjunto de dientes fósiles que proceden de sedimentos marinos de la Formación Jagüel (Maastrichtiano, de la localidad de Bajo Trapalcó, provincia de Río Negro, Patagonia, Argentina. La ictiofauna aquí descripta es la primera para la Formación y se compone de unos seis taxones diferentes de Chondrichthyes (Serratolamna serrata, Squalicorax pristodontus, Cretalamna appendiculata, Carcharias sp., Odontaspis sp. y cf. Pseudohypolophus mcnultyi y dos Teleostei del género Enchodus (aff. E. ferox y aff. E. gladiolus. Serratolamna serrata es el taxón mejor representado del conjunto, y constituye la cita más austral conocida en la distribución de esta especie y el primer registro fósil para Argentina. Los registros de Enchodus, Squalicorax pristodontus y cf. Pseudohypolophus mcnultyi, representan las primeras descripciones de estos taxones para Argentina. Todos los taxones descriptos constituyen un ensamblaje de especies que caracterizan las paleoictiofaunas de los mares del Cretácico Superior de distintas partes del globo, aportando novedosa información para la comprensión de las ictiofaunas Mesozoicas del cono sur sudamericano.This paper describes several fossil teeth coming from marine sediments from the Bajo Trapalcó locality, Río Negro province, Patagonia, Argentina. The ichthyofauna described here is composed by six different chondrichtyan taxa (Serratolamna serrata, Squalicorax pristodontus, Cretalamna appendiculata, Carcharias sp., Odontaspis sp. and cf. Pseudohypolophus mcnultyi and two Teleostei of the genus Enchodus (aff. E. ferox and aff. E. gladiolus. Serratolamna serrata is the most abundant species, and it represents the southernmost record for the species and the first record for Argentina. The records of Enchodus, Squalicorax pristodontus and cf. Pseudohypolophus mcnultyi, constitute the first mention for these taxa in Argentina. The taxa described here characterize the paleoichthyofaunas of the Upper

  18. Discovery of the Middle-Late Triassic elasmobranch ichthyoliths from the Guanling area, Guizhou, SW China

    Institute of Scientific and Technical Information of China (English)

    翟裕生

    2003-01-01

    Abundant Middle-Late Triassic (Ladinian-Carnian) elasmobranch ichthyoliths (microscopic shark dermaldenticles and teeth) from the Zhuganpo and Xiaowa Formations in the Guanling area, Guizhou Province, south-western China, are described and illustrated. The fauna includes a single tooth possibly belonging to Hybodontidaeand 7 paragenera and paraspecies of dermal denticles, i.e.: Lobaticorona cf. floriditurris, Sacrisubcorona cf. circaba-sis, Glabrisubcorona cf. arduidevexa, Parvicorona dacrysulca n. gen. n. sp. s. f., Annulicorona pyramidalis n. gen.n. sp. s. f., and new (?) paragenera A and B. This is the first time that shark dermal denticles are reported fromthe Metapolygnathus polygnathiformis M. nodosus conodont zones. The application of microfossils of chondrichthyesin the strafgraphic division of the Triassic and the intercontinental correlation of Triassic chondrichthyes in south-western China and those in equivalent strata in North America are also discussed.%应用Johns等(1997)的形态分类系统,对首次报道出现于贵州关岭地区中上三叠统的软骨鱼类的微体化石进行了初步研究,描述了其中的1个牙齿化石(可能属于弓鲛鲨科的)和7个鳞片类化石的形态属种,其中包括两个鳞片类化石的新属种,即Lobaticorona cf. floriditurris,Sacrisubcorona cf. circabasis,Glabrisubcorona cf. arduidevexa,Parvi-corona dacrysulca n.gen.et n.sp s f,Annulicorona pyramidalis n.gen.et.n.sp s f,new(?)paragenera A和new(?)paragenera B.还初步探讨了软骨鱼类微体化石在三叠纪地层划分中的应用,以及中国西南部三叠纪软骨鱼类与北荚相当地层中软骨鱼类的洲际对比.

  19. Base composition, selection, and phylogenetic significance of indels in the recombination activating gene-1 in vertebrates

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    Vences Miguel

    2009-12-01

    Full Text Available Abstract Background The Recombination Activating Proteins, RAG1 and RAG2, play a crucial role in the immune response in vertebrates. Among the nuclear markers currently used for phylogenetic purposes, Rag1 has especially enjoyed enormous popularity, since it successfully contributed to elucidating the relationships among and within a large variety of vertebrate lineages. We here report on a comparative investigation of the genetic variation, base composition, presence of indels, and selection in Rag1 in different vertebrate lineages (Actinopterygii, Amphibia, Aves, Chondrichthyes, Crocodylia, Lepidosauria, Mammalia, and Testudines through the analysis of 582 sequences obtained from Genbank. We also analyze possible differences between distinct parts of the gene with different type of protein functions. Results In the vertebrate lineages studied, Rag1 is over 3 kb long. We observed a high level of heterogeneity in base composition at the 3rd codon position in some of the studied vertebrate lineages and in some specific taxa. This result is also paralleled by taxonomic differences in the GC content at the same codon position. Moreover, positive selection occurs at some sites in Aves, Lepidosauria and Testudines. Indels, which are often used as phylogenetic characters, are more informative across vertebrates in the 5' than in the 3'-end of the gene. When the entire gene is considered, the use of indels as phylogenetic character only recovers one major vertebrate clade, the Actinopterygii. However, in numerous cases insertions or deletions are specific to a monophyletic group. Conclusions Rag1 is a phylogenetic marker of undoubted quality. Our study points to the need of carrying out a preliminary investigation on the base composition and the possible existence of sites under selection of this gene within the groups studied to avoid misleading resolution. The gene shows highly heterogeneous base composition, which affects some taxa in particular and

  20. Early vertebrate origin and diversification of small transmembrane regulators of cellular ion transport.

    Science.gov (United States)

    Pirkmajer, Sergej; Kirchner, Henriette; Lundell, Leonidas S; Zelenin, Pavel V; Zierath, Juleen R; Makarova, Kira S; Wolf, Yuri I; Chibalin, Alexander V

    2017-07-15

    Small transmembrane proteins such as FXYDs, which interact with Na(+) ,K(+) -ATPase, and the micropeptides that interact with sarco/endoplasmic reticulum Ca(2+) -ATPase play fundamental roles in regulation of ion transport in vertebrates. Uncertain evolutionary origins and phylogenetic relationships among these regulators of ion transport have led to inconsistencies in their classification across vertebrate species, thus hampering comparative studies of their functions. We discovered the first FXYD homologue in sea lamprey, a basal jawless vertebrate, which suggests small transmembrane regulators of ion transport emerged early in the vertebrate lineage. We also identified 13 gene subfamilies of FXYDs and propose a revised, phylogeny-based FXYD classification that is consistent across vertebrate species. These findings provide an improved framework for investigating physiological and pathophysiological functions of small transmembrane regulators of ion transport. Small transmembrane proteins are important for regulation of cellular ion transport. The most prominent among these are members of the FXYD family (FXYD1-12), which regulate Na(+) ,K(+) -ATPase, and phospholamban, sarcolipin, myoregulin and DWORF, which regulate the sarco/endoplasmic reticulum Ca(2+) -ATPase (SERCA). FXYDs and regulators of SERCA are present in fishes, as well as terrestrial vertebrates; however, their evolutionary origins and phylogenetic relationships are obscure, thus hampering comparative physiological studies. Here we discovered that sea lamprey (Petromyzon marinus), a representative of extant jawless vertebrates (Cyclostomata), expresses an FXYD homologue, which strongly suggests that FXYDs predate the emergence of fishes and other jawed vertebrates (Gnathostomata). Using a combination of sequence-based phylogenetic analysis and conservation of local chromosome context, we determined that FXYDs markedly diversified in the lineages leading to cartilaginous fishes (Chondrichthyes) and

  1. Species identification of shark fins and cartilages with FINS method%FINS方法鉴定鱼翅和鲨鱼软骨的鲨鱼种类

    Institute of Scientific and Technical Information of China (English)

    黄文胜; 韩建勋; 董洁; 邓婷婷; 王娉; 吴亚君; 陈颖

    2011-01-01

    Shark species such as Basking shark(Cetorhinus maximus), Great White shark(Carcharodon carcharias), Whale shark(Rhincodon typus) are some of the most endangered trade fish in the world. However, identification of these species in traded forms, fins and cartilages, may be difficult depending on the presentation of the products, which may hamper conservation efforts on trade control. In this paper, we established a genetic methodology, forensically Informative nucleotide sequencing(FINS), for species identification in shark fins and cartilages. By blastning the mitochondrial sequences of 5 shark species Heterodontus francisci, Chiloscyllium plagiosum, Squalus acanthia, Scyliorhinus canicula, Mustelus manazo, the degenerated primers for amplification of 5' region of the cytochrome oxidase I (COX I) gene were designed and synthesized. The polymerase chain reaction was employed to obtain a 680 bp amplicon from the mitochondrial COX I gene with touchdown cycling program to circumvent spurious priming and the products were purified and two directional sequenced. The sequences of COX I gene from individual sample and the reference sequences in the genebank were analyzed using a genetic distance method by which species the sample belong to determined. 126 different samples of commercial shark fins and cartilages obtained in Guangdong shark fin processing factories and fishery markets were analyzed and showing that FINS is a suitable technique for species identification of shark fins. The results also showed that the most shark fins come from blue shark, others come from the Porbeagle, Mako, the Caribbean sharpnose shark, the Milk shark, the Australian weasel shark, the Narrownose smooth-hound shark, the scalloped hammerhead shark and guitarfish rays, Callorhinchus callorhynchus and Hydrolagus spp., but none of the species on red list of the convention on International trade in endangered species of wild fauna and Flora(CITES)was founded in any

  2. DISCOVERY OF FISH MICROREMAINS IN THE GUFENG FORMATION AT THE LUOJIABA SECTION FROM JIANSHI, WEST HUBEI%鄂西建始罗家坝剖面孤峰组鱼类微体化石的发现

    Institute of Scientific and Technical Information of China (English)

    毛羽; 马强分; 冯庆来

    2013-01-01

    笔者在对湖北恩施建始地区孤峰组进行放射虫和牙形刺的处理研究过程中发现了丰富的鱼类微体化石.对其中部分化石进行了初步的鉴定,软骨鱼纲和硬骨鱼纲鱼类微体化石同时被发现.通过与其它产地同时期的鱼类微体化石相比较,其特征明显:层位集中、分异度高、丰度大、个体整体偏小.由于该研究区地处古赤道地区东特提斯海,气候温暖,上升流发育,海水缺氧,因此发育了一套黑色深水沉积的岩系——孤峰组.而已被报道的其它二叠纪鱼类微体化石的产地并不是此类独特的海洋环境.同时,在其它华南地区孤峰组岩层中也未见该类化石的报道.因此,结合环境对现代鱼类生命活动的影响规律,对当时的鱼类生物与环境展开讨论,间接反映了中二叠世扬子板块建始地区的古地理古气候和古环境.%Abundant microremains of fish were found during processing the samples for radiolarian and conodonts from the Jianshi area in Enshi,Hubei.Some fossils,which were identified preliminarily,belong to Chondrichthyes and Osteichthyes.Comparing to the other coeval microremains,the fish microremains in this study has the following distinct characteristics:high diversity and richness together with smaller individual size.In the Middle Permian,this area was located in the equatorial region of the eastern Tethys,which was characterized by warm humid climate condition,development of upwelling and anoxic seawater.A series of deep-water black deposits,namely the Gufeng Formation,was developed.Other Permian fish microremains reported previously were not come from such unique marine environment.Meanwhile,similar fossil was not found in the Gufeng Formation from other places in South China.In this study,the relationship between fish biology and palacoenvironment conditions were discussed in terms of the influence of environment conditions on the living fish biology,which may reflects the

  3. The taxonomic diversity of fish community in the coastal waters of Xiamen%厦门海域鱼类群落分类学多样性的研究

    Institute of Scientific and Technical Information of China (English)

    黄良敏; 谢仰杰; 李军; 张雅芝; 王家樵

    2013-01-01

    根据厦门海域鱼类种类组成历史资料和调查资料,系统整理了厦门海域的鱼类总名录和现有名录,并应用分类学等级多样性指数和分类差异变异指数分析了厦门海域鱼类群落分类学多样性的时空变化.结果表明:厦门海域有记录鱼类共649种;现有鱼类有331种,隶属2纲22目90科181属,其中软骨鱼纲共5目9科9属15种,辐鳍鱼纲共17目81科172属316种.厦门海域鱼类总名录的等级多样性指数△+和分类差异变异指数(A)+分别为79.267和220.96;现有鱼类群落分类多样性指数△+和分类差异指数(A)+分别为77.504和245.34.分类多样性指数△+在冬、春季较高,秋季次之,而夏季最低;而分类差异指数(A)+夏季较高,秋季次之,冬春季较低.秋季和冬季鱼类组成的相似度最高,其次为夏季,最后为春季.与历史总名录相比,厦门海域的现有鱼类群落分类学范围较小,生态幅变窄,群落稳定性较差.%Based on literature and survey data of fish composition collected by bottom trawl investigation from 2006 to 2007 in Xiamen coastal waters, the fish fauna was set up, fish community and the taxonomic diversity and distinctness by using taxonomic diversity △+ and taxonomic distinctness △+ were analyzed. The results show that: there were 649 species of fishes recorded in Xiamen coastal waters. 331 species of fishes were available at present, belonging to 2 classes, 22 orders, 90 families and 181 genera, as for the Chondrichthyes fishes were composed of 5 orders, 9 families, 9 genera and 15 species, while the Actinopterygii fishes were composed of 17 orders, 81 families, 172 genera and 316 species. The taxonomic diversity △+ and taxonomic distinctness △+ of the fish community master list in Xiamen coastal waters were 79. 267 and 220. 96, 77. 504 and 245. 34 at present, respectively. The taxonomic diversity △+ in winter and spring was higher than summer and autumn, and it was lowest in summer

  4. Nekton resources in northeast Beibu Gulf%北部湾东北部游泳生物资源现状

    Institute of Scientific and Technical Information of China (English)

    袁华荣; 陈丕茂; 贾晓平; 唐振朝; 秦传新; 余景; 蔡文贵; 舒黎明

    2011-01-01

    2009年至2010年对北部湾东北部海域游泳生物调查研究表明,该海域共有游泳生物300种,其中鱼类有209种(硬骨鱼类205种,软骨鱼类4种),隶属15目、70科、119属;甲壳类76种;头足类15种.底层鱼类100种,近底层鱼类72种,中上层鱼类29种,岩礁性鱼类8种,分别占鱼类总数的47.85%,34.45%,13.87%和3.83%.暖水性鱼类153种,暖温性鱼类55种,冷温性鱼类1种,分别占鱼类总数的73.20%,26.32%和0.48%.游泳生物种类数季节变化为夏季>秋季>春季>冬季;资源密度指数季节变化为夏季>秋季>春季>冬季;渔业资源密度随季节变化为夏季>秋季>春季>冬季,渔业资源年平均资源密度为522.925 kg·km~,约相当于该海域原始渔业资源密度的1/10;生物多样性指数以夏、秋季最高.估算了北部湾东北部海域潜在渔业资源量为1.092×105t·a-1,最大可捕量为5.460×104t·a-1.比较了北部湾渔业资源的历史变动情况,对渔业资源的进一步养护和管理提出了建议.%The nekton in the northeast waters of Beibu Gulf had been investigated during 2009 ~2010. There are 300 species of nektons in the waters, among which 209 are fish (205 species of osteichthyes, 4 species of chondrichthyes), belonging to 15 orders, 70 families and 119 genera. Seventy-six crustanceans and 15 cephalopods are identified in the area. One hundred species of benthic fishes, 72 species of epibenthic fishes, 29 species of pelagic fishes and 8 species rockfish occupy 47. 85%, 34. 45% , 13. 87% and 3. 83% of the total species of fishes, respectively; and 153 species of warm-water fish, 55 species of warm-temperature fish and 1 species of cold-temperature fish occupy 73. 20%, 26. 32% and 0. 48% of the total species of fishes, respectively. The seasonal variation in the number of nekton species: summer > autumn > spring > winter; density index of resources: summer > autumn > spring > winter;density of fishery resources

  5. Origin and evolution of gnathostome dentitions: a question of teeth and pharyngeal denticles in placoderms.

    Science.gov (United States)

    Zerina, Johanson; Smith, Moya M

    2005-05-01

    The fossil group Placodermi is the most phylogenetically basal of the clade of jawed vertebrates but lacks a marginal dentition comparable to that of the dentate Chondrichthyes, Acanthodii and Osteichthyes (crown-group Gnathostomata). The teeth of crown-group gnathostomes are part of an ordered dentition replaced from, and patterned by, a dental lamina, exemplified by the elasmobranch model. A dentition recognised by these criteria has been previously judged absent in placoderms, based on structural evidence such as absence of tooth whorls and typical vertebrate dentine. However, evidence for regulated tooth addition in a precise spatiotemporal order can be observed in placoderms, but significantly, only within the group Arthrodira. In these fossils, as in other jawed vertebrates with statodont, non-replacing dentitions, new teeth are added at the ends of rows below the bite, but in line with biting edges of the dentition. The pattern is different on each gnathal bone and probably arises from single odontogenic primordia on each, but tooth rows are arranged in a distinctive placoderm pattern. New teeth are made of regular dentine comparable to that of crown-gnathostomes, formed from a pulp cavity. This differs from semidentine previously described for placoderm gnathalia, a type present in the external dermal tubercles. The Arthrodira is a derived taxon within the Placodermi, hence origin of teeth in placoderms occurs late in the phylogeny and teeth are convergently derived, relative to those of other jawed vertebrates. More basal placoderm taxa adopted other strategies for providing biting surfaces and these vary substantially, but include addition of denticles to the growing gnathal plates, at the margins of pre-existing denticle patches. These alternative strategies and apparent absence of regular dentine have led to previous interpretations that teeth were entirely absent from the placoderm dentition. A consensus view emerged that a dentition, as developed

  6. 大亚湾春秋季鱼类种类组成及年龄结构分析%Species composition and age structure of fish in the Dava Bay in spring and autumn

    Institute of Scientific and Technical Information of China (English)

    金亮; 徐华林; 张志敏; 杨锡凯; 王英永; 卢昌义

    2011-01-01

    2006年4月和9月对大亚湾海域通过拖网和流刺网捕获的鱼类进行初步调查.结果表明,渔获物中出现18目76科135属200种鱼类,其中软骨鱼纲4目5科5属6种,占调查鱼类总种数的3.0%;硬骨鱼纲14目71科130属194种,占调查鱼类总种数的97.0%.根据其适温类型可分为暖水性种、暖温性种和冷温性种,其中暖水性鱼类有183种,占总种数的91.5%;暖温性鱼类有16种,占总种数的8.0%;冷温性鱼类仅有1种,占总种数的0.5%.渔获物中底层和近底层鱼类占多数,其中,底层鱼类共有74种,占总种数的37.0%;近底层鱼类共有68种,占总种数的34.0%;中上层鱼类共有45种,占总种数的22.5%;岩礁鱼类有13种,占总种数的6.5%.大亚湾鱼类的年龄普遍偏低,以1 a龄鱼为主.与相邻海区鱼类区系特征比较,大亚湾海域具有我国热带和亚热带性海湾的鱼类区系特征.%An investigation of fish in Daya Bay was conducted in April and September 2006 using a trawl and drift net. The results showed that there were 200 species of fish belonging to 135 genera in 76 families of 18 orders. Of these, 6 species in 5 genera, 5 families, and 4 orders belonged to Chondrichthyes, and 194 species in 130 genera,71 families, and 14 orders belonged to Osteiehthyes, accounting for 3.0% and 97.0%, respectively. Based on the temperature nature of the fauna, the fish in Daya Bay may be grouped into three types, with warm-water species,warm-temperature species and cold-temperature species accounting for 91.5% ( 183 species), 8.0% ( 16 species) and 0. 5% ( one species), respectively. According to the diversity of the habitable environment, demersal fishes were the most abundant, accounting for 37.0% (74 species), followed by near demersal and pelagic fish, accounting for 34.0% (68 species) and 22. 5% (45 species ), respectively, and reef fish only accounted for 6.5% ( 13 species). The age structure of the fish primarily consisted of one age

  7. Gökova Körfezi'nde küçük ölçekli balıkçılıkta birim çabaya düşen av miktarı (CPUE ve av kompozisyonu

    Directory of Open Access Journals (Sweden)

    Hakkı Dereli

    2015-09-01

    Full Text Available Gökova Körfezi’nde avcılık yapan küçük ölçekli balıkçı gemilerinin uzatma ağı ve parakete av kompozisyonları ve birim çabaya düşen av miktarları (CPUE, Temmuz 2009 – Mayıs 2011 tarihleri arasında yürütülen çalışmalarla tespit edilmiştir. Toplam 16 deniz çalışması (uzatma ağı ile 5, parakete ile 11 ticari balıkçıların tekne ve av araçlarıyla yürütülmüştür. Balıkçılık çabası (f, CPUE ve günlük av miktarını hesaplamak için ise karaya çıkış noktalarında rasgele seçimle 131 örnekleme (72 kez uzatma ağı, 59 kez paraketeyle gerçekleştirilmiştir. Her iki av aracı birlikte değerlendirildiğinde, Teleostei grubundan 27, Crustacea grubundan 1, Cephalapoda grubundan 2 ve Chondrichthyes grubundan 1 olmak üzere toplam 31 tür tespit edilmiştir. Uzatma ağı ile 19 tür, parakete ile 16 tür yakalanmıştır. Karaya çıkarılan ürün içerisinde, uzatma ağlarında ağırlıklı olarak Pagellus erythrinus, Trachurus mediterraneus ve Scomber japonicus, parakete balıkçığında ise Sparus aurata, Dicentrarchus labrax ve Pagellus erythrinus türleri tespit edilmiştir. Uzatma ağları av kompozisyonu içinde ticari olmayan türlerin oranı (% 50, paraketeninkinden daha yüksektir (% 12. Ortalama CPUE, uzatma ağı için 15,5 ± 19,8 kg/30 posta ağ/gün ve parakete için 1,7 ± 2,8 kg/100 iğne/gün, tekne başına günlük av (kg ortalaması ise uzatma ağı için 10,8 ± 11,0 kg/tekne/gün ve parakete için 5,2 ± 4,3 kg/tekne/gün olarak hesaplanmıştır. Ortalama CPUE değerleri açısından iki av aracı arasında (t:-11,065; p:0,000 ve kooperatifler arasında (uzatma ağı, t:4,382; p:0,000; parakete, t:3,973; p:0,000 istatistiki olarak anlamlı farklılık tespit edilmiştir. Gökova Körfezi’nde uzatma ağı balıkçılığında yakalanan tür sayısının yıllar içerisinde düşüş gösterdiği ve ortalama CPUE değerinin arttığı belirlenmiştir. Parakete bal

  8. 西伯利亚鲟侧线神经丘发育过程的观察%OBSERVATION ON THE DEVELOPMENT OF THE LATERAL LINE NEUROMAST OF SIBERIAN STURGEON (ACIPENSER BAERII)

    Institute of Scientific and Technical Information of China (English)

    程千千; 施志仪; 陈晓武; 宋佳坤; 轩兴荣

    2011-01-01

    研究对西伯利亚鲟(Acipenser baerii)的胚后幼鱼进行石蜡切片HE染色,同时利用荧光染料DiA[4-(4-Diethylaminostyryl)-1-methylpyridinium iodide]对侧线管中侧线神经丘毛细胞特异性标记的特点,示踪了西伯利亚鲟胚后仔鱼各个时期侧线神经丘分化发育的过程.结果显示,西伯利业鲟侧线管内侧线神经丘毛细胞如纤毛状,呈竖立紧密排列.出膜3d仔鱼眼眶后神经基板发育分化活动剧烈,出膜10d的仔鱼眼眶后方的神经基板分化出眼眶上下侧线神经丘的两个分支,同时眼眶后神经基板进一步向后分化发育在眼眶后部形成躯干侧线神经丘,但整个侧线神经丘还未完全发育完成,待出膜15d时,眼眶上下和躯干侧线神经丘已基本发育完全,出膜22d的仔鱼侧线神经丘发育基本完成.研究为今后深入研究西伯利亚鲟侧线发育过程中的神经分化发育、细胞迁移奠定了初步形态学基础.%Acipenseriformes fish is a kind of the ancient chondrichthyes fish, and Siberian sturgeon (Acipenser baerii) plays an important part in the evolutionary history of vertebrates. Lateral line neuromast is the key part of the lateral line system-a very important sense organ of fish. Therefore, it is necessary to pay attention to the development of the lateral line neuromast of the Siberian sturgeon. In order to observing the morphology and tracking the development of lateral line neuromast of the Siberian sturgeon larvae in the different development periods after hatching. The 5μm of the paraffin sections of the adult fish of the Siberian sturgeon were prepared and then stained with HE. Meanwhile, the Siberian sturgeon larvae in different periods after hatching stained with 10μmol/L DiA [4-(4-Diethylaminostyryl)-lmethylpyridinium iodide] which can be used as the neuromast specific markers. The results showed morphology of the neuromast in the lateral line canal: The hair cells erected and arranged closely

  9. A Middle-Late Devonian fish fauna from the Sierra de Perijá, western Venezuela, South America

    Directory of Open Access Journals (Sweden)

    G. C. Young

    2002-01-01

    palaeomagnetic data. Es wird eine neue devonische Fischfauna aus dem Gebiet zwischen Caño Colorado und Rio Socuy, Sierra de Perijá, beschrieben. Die Funde stammen aus zwei Lokalitäten und mehreren Horizonten innerhalb der Campo Chico Formation, die auf Grundlage von Untersuchungen der Pflanzen- und Sporenfunde dem Zeitabschnitt Givetium-Frasnium zugeordnet werden. Placodermen sind durch den Antiarchen Bothriolepis perija n. sp. häufig vertreten. Sie sind mit Arten der Aztec-Fischfauna von Viktoria Land, Antarktis, verwandt. Ein zweiter Antiarche, der Venezuelepis mingui n. g. n. sp. ist eng mit einer Spezies aus der Antarktis verwandt, die ebenfalls dieser neuen Gattung zugeschrieben wird. Fragmentarische Reste eines phyllolepiden Placodermen weisen Ähnlichkeiten mit der Gattung Austrophyllolepis aus dem Südosten Australiens auf. Wirbel eines Chondrichthyer werden vorläufig den Antarctilamnidae zugeschrieben. Acanthodir-Reste schließen das weitverbreitete Taxon Machaeracanthus ein. Osteichthyer sind durch Schuppen und Zähne osteolepider Sarcopterygier und Dipnoi vertreten. Andere Schuppen, denen die Cosminschicht fehlt, gehören vermutlich zu einem anderen Haupttaxon. Damit ist durch diese Fauna der erste Nachweis für das Vorkommen der drei Hauptfischgruppen Antiarchi, phyllolepide Placodermi und Dipnoi im Devon Südamerikas erbracht. Sie sind auch auf den meisten anderen Kontinenten weit verbreitet. Obwohl Invertebraten und Pflanzen aus derselben Zeit sehr denen aus dem Osten Nordamerikas ähneln, weisen die endemischen Elemente in der Fischfauna auf eine Affinität zu Gondwana hin. Phyllolepide Placodermen sind im Givetium-Frasnianium Australiens verbreitet, aber erst aus dem Famennium in der Nordhemisphere bekannt. Das Auftreten eines neuen Phyllolepiden weitet den Vorkommensbereich über die nördliche Linie des paläozoischen Gondwanas hinaus aus. Alter und Verwandtschaftsbeziehungen dieser neuen Fischfauna stimmen mit dem Modell der biotischen Verbreitung