Sameer M. Padhye
Full Text Available The present study is a report on the distribution and assemblages of large branchiopods from the Western Ghats of Maharashtra. Different types of water bodies were sampled including pools on lateritic outcrops. Eight species of large branchiopods were found in 72 samples collected over a period of 4 years. We found 7 large branchiopod species in rock pools, while the cyclestheriid Cyclestheria hislopi was observed only in rivers and water reservoirs. In twenty-five percent of the samples multiple species co-occurred with a maximum of 4 species in a single sample. Streptocephalus dichotomus was the most commonly observed species while Streptocephalus sahyadriensis was noted only in rock pools. Altitude and aquatic vegetation were identified as important factors for the distribution of large branchiopods in the studied area. Triops granarius was the species most commonly found to be co-occurring with other species, followed by S. sahyadriensis. Cyclestheria hislopi and Eulimnadia indocylindrova always occurred alone.
Gueriau, Pierre; Rabet, Nicolas; Clément, Gaël; Lagebro, Linda; Vannier, Jean; Briggs, Derek E G; Charbonnier, Sylvain; Olive, Sébastien; Béthoux, Olivier
Branchiopod crustaceans are represented by fairy, tadpole, and clam shrimps (Anostraca, Notostraca, Laevicaudata, Spinicaudata), which typically inhabit temporary freshwater bodies, and water fleas (Cladoceromorpha), which live in all kinds of freshwater and occasionally marine environments [1, 2]. The earliest branchiopods occur in the Cambrian, where they are represented by complete body fossils from Sweden such as Rehbachiella kinnekullensis  and isolated mandibles preserved as small carbonaceous fossils [4-6] from Canada. The earliest known continental branchiopods are associated with hot spring environments  represented by the Early Devonian Rhynie Chert of Scotland (410 million years ago) and include possible stem-group or crown-group Anostraca, Notostraca, and clam shrimps or Cladoceromorpha [8-10], which differ morphologically from their modern counterparts [1, 2, 11]. Here we report the discovery of an ephemeral pool branchiopod community from the 365-million-year-old Strud locality of Belgium. It is characterized by new anostracans and spinicaudatans, closely resembling extant species, and the earliest notostracan, Strudops goldenbergi . These branchiopods released resting eggs into the sediment in a manner similar to their modern representatives [1, 2]. We infer that this reproductive strategy was critical to overcoming environmental constraints such as seasonal desiccation imposed by living on land. The pioneer colonization of ephemeral freshwater pools by branchiopods in the Devonian was followed by remarkable ecological and morphological stasis that persists to the present day. PMID:26776738
Weber, W; Woollett, J
Condor Country Consulting conducted surveys for listed branchiopods in the 2002-2003 wet season to complete requirements of the Guidelines (USFWS 1996) used to determine the distribution of federally-listed branchiopods within the study area. The first survey was performed during the previous wet season (2001-2002). The 2002-2003 wet season survey, combined with the previous season's survey, is intended to provide LLNL with information that will assist them in determining the effects of the proposed action on federally listed branchiopods and provide information useful in the preparation of the associated environmental documentation. It is also expected to satisfy the survey requirements of the USFWS. For the purpose of this report, the term branchiopod refers specifically to phyllopodous branchiopods and not cladocerans. Fairy shrimp, tadpole shrimp, and clam shrimp are all categorized as phyllopodous branchiopods and are currently the only members of the Class Branchiopoda that contain species that are listed under the federal Endangered Species Act. Although cladocerans are branchiopods and were found on the site, they are only referred to by the Order in this report because they are not the target species of this study.
Weber, W; Woollett, J
Condor County Consulting on behalf of Lawrence Livermore National Laboratory (LLNL) has performed wet season surveys for listed branchiopods at Site 300, located in eastern Alameda County and western San Joaquin County. LLNL is collecting information for the preparation of an EIS covering ongoing explosives testing and related activities on Site 300. Related activities include maintenance of fire roads and annual control burns of approximately 607 hectares (1500 acres). Control burns typically take place on the northern portion of the site. Because natural branchiopod habitat is sparse on Site 300, it is not surprising that listed branchiopods were not observed during this 2001-2002 wet season survey. Although the site is large, a majority of it has topography and geology that precludes the formation of static seasonal pools. Even the relatively gentle topography of the northern half of the site contains few areas where water pools for more than two weeks. The rock outcrops found on the site did not provide suitable habitat for listed branchiopods. Most of the habitat available to branchiopods on the site is puddles that form in roadbeds and dry quickly. The one persistent pool on the site, the larger of the two modified vernal pools and the only one to fill this season, is occupied by two branchiopod species that require long-lived pools to reach maturity. In short, there is little habitat available on the site for branchiopods and most of the habitat present is generally too short-lived to support the branchiopod species that do occur at Site 300.
Lawrence Livermore National Laboratory (LLNL) requested that Condor Country Consulting, Inc. (CCCI) perform wet season surveys and manage the dry season sampling for listed branchiopods in two ponded locations within the Site 300 Experimental Test Site. Site 300 is located in Alameda and San Joaquin Counties, located between the Cities of Livermore and Tracy. The two pool locations have been identified for possible amphibian enhancement activities in support of the Compensation Plan for impacts tied to the Building 850 soil clean-up project. The Building 850 project design resulted in formal consultation with the U.S. Fish and Wildlife Service (USFWS) as an amendment (File 81420-2009-F-0235) to the site-wide Biological Opinion (BO) (File 1-1-02-F-0062) in the spring of 2009 and requires mitigation for the California tiger salamander (AMCA, Ambystoma californiense) and California red-legged frog (CRLF, Rana draytonii) habitat loss. Both pools contain breeding AMCA, but do not produce metamorphs due to limited hydroperiod. The pool to the southeast (Pool BC-FS-2) is the preferred site for amphibian enhancement activities, and the wetland to northwest (Pool OA-FS-1) is the alternate location for enhancement. However, prior to enhancement, LLNL has been directed by USFWS (BO Conservation Measure 17 iii) to 'conduct USFWS protocol-level branchiopod surveys to determine whether listed brachiopod species are present within the compensation area.' CCCI conducted surveys for listed branchiopods in the 2009-2010 wet season to determine the presence of federally-listed branchiopods at the two pools (previous surveys with negative findings were performed by CCCI in 2001-2002 and 2002-2003 onsite). Surveys were conducted to partially satisfy the survey requirements of the USFWS 'Interim Survey Guidelines to Permittees for Recovery Permits under Section 10(a)(1)(A) of the Endangered Species Act for the Listed Vernal Pool Branchiopods' ('Guidelines, USFWS
Full Text Available We conducted a survey of large branchiopods (Crustacea, Branchiopoda of the major salt lakes of Algeria, particularly those of the eastern Hauts Plateaux. The aim of the survey was to complement a previous survey that focused on the freshwater habitats of Numidia, northeast Algeria. The study revealed 8 species, with one taxon new to Algeria and North Africa (Chirocephalus salinus. Data on the status, phenology and habitats of collected and previously known species are presented for 19 taxa. The distribution of many species has been greatly extended and the co-occurrence of Artemia tunisiana and Branchinella spinosa has been recorded. The studied salt lakes, owing to a large production of fairy shrimps, support a great number of wintering and breeding waterbirds, but are subject to increasing human pressure.
Full Text Available Sex-determining mechanisms are diverse among animal lineages and can be broadly divided into two major categories: genetic and environmental. In contrast to genetic sex determination (GSD, little is known about the molecular mechanisms underlying environmental sex determination (ESD. The Doublesex (Dsx genes play an important role in controlling sexual dimorphism in genetic sex-determining organisms such as nematodes, insects, and vertebrates. Here we report the identification of two Dsx genes from Daphnia magna, a freshwater branchiopod crustacean that parthenogenetically produces males in response to environmental cues. One of these genes, designated DapmaDsx1, is responsible for the male trait development when expressed during environmental sex determination. The domain organization of DapmaDsx1 was similar to that of Dsx from insects, which are thought to be the sister group of branchiopod crustaceans. Intriguingly, the molecular basis for sexually dimorphic expression of DapmaDsx1 is different from that of insects. Rather than being regulated sex-specifically at the level of pre-mRNA splicing in the coding region, DapmaDsx1 exhibits sexually dimorphic differences in the abundance of its transcripts. During embryogenesis, expression of DapmaDsx1 was increased only in males and its transcripts were primarily detected in male-specific structures. Knock-down of DapmaDsx1 in male embryos resulted in the production of female traits including ovarian maturation, whereas ectopic expression of DapmaDsx1 in female embryos resulted in the development of male-like phenotypes. Expression patterns of another D. magna Dsx gene, DapmaDsx2, were similar to those of DapmaDsx1, but silencing and overexpression of this gene did not induce any clear phenotypic changes. These results establish DapmaDsx1 as a key regulator of the male phenotype. Our findings reveal how ESD is implemented by selective expression of a fundamental genetic component that is
Ripoll Rodríguez, J.
Full Text Available Large branchiopods (Crustacea, Branchiopoda, Anostraca, Notostraca from Málaga province, Spain (2012/2013 hydrological year This paper presents the occurrence of the large branchiopods detected during a survey carried out in the province of Málaga (Andalusia, southern Spain. Five species (Branchipus cortesi, Chirocephalus diaphanus, Streptocephalus torvicornis, Triops mauritanicus aggr. and Phallocryptus spinosa were recorded at 90 sampled wetlands.
Rogers, D. Christopher; Schwentner, Martin; Olesen, Jørgen; Richter, Stefan
We introduce this Branchiopoda Special Issue of the Journal of Crustacean Biology, providing a brief outline of the 13 research papers presented at the 8th International Crustacean Congress in Frankfurt, Germany, August 2014. We also discuss the current status and direction of research on the large branchiopod crustaceans.
Olesen, Jorgen; Fritsch, Martin; Grygier, Mark J.
For comparison with the remarkable larvae of the laevicaudatan (clam shrimp) Lynceus brachyurus, a basic description of the larval sequence of another laevicaudatan branchiopod, the Japanese Lynceus biformis, is provided. Four larval stages have been identified, ranging in size from 258 to 560 mu m...
Full Text Available Zooplankton in temporary waters produces resting stages to survive recurrent dry periods. Branchiopod crustaceans (i.e., cladocerans, large branchiopods overcome these periods in the form of resting eggs buried in the sediment. Examining the diversity in the resting egg banks allows for a more accurate estimation of biodiversity of aquatic ecosystems than looking only at the active communities. The isolation of resting eggs from the sediment may be achieved by the sugar flotation method, which usually results in higher density and diversity than untreated samples (i.e., incubated in the sediment. We tested the effect of sugar isolation and centrifugation on the hatching success of resting eggs already isolated from sediment in order to reveal any direct effects on hatching success. We used four different branchiopod species, Daphnia magna, Moina brachiata, Branchinecta orientalis, and Triops cancriformis. Although we hypothesised that osmotic stress caused by sugar and centrifuging influence the hatching success either positively (e.g., faster activation as a response to osmotic changes or negatively (destroyed by centrifugation, we found no significant difference either in the timing or rate of hatching between centrifuged and non-centrifuged eggs. Once the eggs are exposed to light and/or oxygen availability by being removed from the sediment, the centrifugation process does not have any additional effect on their hatching. Regardless of treatment, we found a significant difference in the hatching timing in the two major groups, with large branchiopods hatching earlier than cladocerans. We found that the sugar flotation method itself does not influence the hatching fraction of branchiopod resting eggs (implying no adverse effect on their viability and its success in enhancing hatching can be attributed to its efficiency in removing eggs from the sediment.
Theodora Farmaki; Abatzopoulos, Theodore J.; Baxevanis, Athanasios D.; Stefania Maniatsi; Ilias Kappas
Genealogical concordance is a critical overlay of all phylogenetic analyses, irrespective of taxonomic level. To assess such patterns of congruence we have compiled and derived sequence data for two mitochondrial (16S rRNA, COI) and two nuclear (ITS1, p26) markers in 14 American populations of the hypersaline branchiopod Artemia franciscana. Cladistic analysis revealed three reciprocally monophyletic mitochondrial clades. For nuclear DNA, incomplete lineage sorting was evident presumably as a...
Negrea, S.; Botnariuc, N.; Dumont, H.J.
We present a cladistic analysis of all branchiopod groups, using a total of 42 morphological characters. The class Branchiopoda is composed of five superorders and 11 orders (nine recent, two fossil). The orders Ctenopoda, Anomopoda and Onychopoda form a monophyletic group, combined in the superorder Cladocera. The order Haplopoda, the fourth so-called cladoceran order (s. lat.), belongs to a new monotypic superorder, the Leptodorida. The circumtropical Cyclesteria hislopi is the sole represe...
Pérez López, Alberto; Fernández, J.; Solé de Porta, N.; Márquez Aliaga, Ana
Theree differents lithology can be differenciated basically in t he Triassic of the central sector of Betic: carbona tes (facies Muschelk alk), terrigenou s (facies Keuper) and evaporites (facies Keuper). The study of several ou t crops in this area allow to know better the paleoecologica ls aspects of Triassic, and to review the stratigraphic paleontology. In the carbonate section fosiil record is formed by molluscs and branchiopods. The occurrence of Costatoria goldfussi and Enantiostreon...
Blaxter Mark L; Colbourne John K; Conlon Claire; McTaggart Seanna J; Little Tom J
Abstract Background Branchiopod crustaceans in the genus Daphnia are key model organisms for investigating interactions between genes and the environment. One major theme of research on Daphnia species has been the evolution of resistance to pathogens and parasites, but lack of knowledge of the Daphnia immune system has limited the study of immune responses. Here we provide a survey of the immune-related genome of D. pulex, derived from the newly completed genome sequence. Genes likely to be ...
Nur Syafiqah Mohamad Ishak; Yasuhiko Kato; Tomoaki Matsuura; Hajime Watanabe
Identifying the genes required for environmental sex determination is important for understanding the evolution of diverse sex determination mechanisms in animals. Orthologs of Drosophila orphan receptor Fushi tarazu factor-1 (Ftz-F1) are known to function in genetic sex determination. In contrast, their roles in environmental sex determination remain unknown. In this study, we have cloned and characterized the Ftz-F1 ortholog in the branchiopod crustacean Daphnia magna, which produces males ...
Swinstrom, Kirsten; Caldwell, Roy; Fourcade, H. Matthew; Boore, Jeffrey L.
We report the first complete mitochondrial genome sequences of stomatopods and compare their features to each other and to those of other crustaceans. Phylogenetic analyses of the concatenated mitochondrial protein-coding sequences were used to explore relationships within the Stomatopoda, within the malacostracan crustaceans, and among crustaceans and insects. Although these analyses support the monophyly of both Malacostraca and, within it, Stomatopoda, it also confirms the view of a paraphyletic Crustacea, with Malacostraca being more closely related to insects than to the branchiopod crustaceans.
Gabrion, C; MacDonald, G
Examination of Artemia sp. (Crustacé, Anostracé) for natural infection by cysticercoids of Flamingolepis liguloides, Cestode of the Flamingo (Phoenicopterus ruber) shows the presence of three other cysticercoids of cestode parasites of the Flamingo in the hemocoele of the Branchiopode. A fourth one is reported as the cysticercoid of Eurycestus avoceti, Clark, 1954, which parasitizes the Avocet (Recurvirostra avosetta). The systematic position of this Cestode is always unknown. This report shows the importance of Artemia in the life cycle of Cestodes of Anseriforms and Charadriiforms birds in saline lagoons. PMID:7406422
Ephemeral aquatic habitats in Wupatki National Monument vary from naturally formed pools in arroyos over 5000 years old, to constructed catchment basins with ages estimated at 60-1000+ years old, and borrow pits and stock ponds 30-60 years old. The different ages of these pools provide different histories of colonization by amphibians and aquatic invertebrates, especially temporary pool specialists such as spadefoot toads and branchiopod crustaceans. Ten pools of five different origins and ages were surveyed in August and/or September 1997 for aquatic organisms; a total of 13 surveys were conducted. Twenty-two taxa were found, with the number of species in a pool during any survey ranging from one to 10. Species composition of the communities changed from one sampling date to the next within individual pools. Community structure is an amalgam of species with different dispersal mechanisms that are influenced by different pool characteristics. Age appears to have little effect overall, but may have influenced branchiopod presence/absence. Distance to permanent water, frequency of disturbance, and current pool size were correlated with presence/absence of some species.
Nur Syafiqah Mohamad Ishak
Full Text Available Identifying the genes required for environmental sex determination is important for understanding the evolution of diverse sex determination mechanisms in animals. Orthologs of Drosophila orphan receptor Fushi tarazu factor-1 (Ftz-F1 are known to function in genetic sex determination. In contrast, their roles in environmental sex determination remain unknown. In this study, we have cloned and characterized the Ftz-F1 ortholog in the branchiopod crustacean Daphnia magna, which produces males in response to environmental stimuli. Similar to that observed in Drosophila, D. magna Ftz-F1 (DapmaFtz-F1 produces two splicing variants, αFtz-F1 and βFtz-F1, which encode 699 and 777 amino acids, respectively. Both isoforms share a DNA-binding domain, a ligand-binding domain, and an AF-2 activation domain and differ only at the A/B domain. The phylogenetic position and genomic structure of DapmaFtz-F1 suggested that this gene has diverged from an ancestral gene common to branchiopod crustacean and insect Ftz-F1 genes. qRT-PCR showed that at the one cell and gastrulation stages, both DapmaFtz-F1 isoforms are two-fold more abundant in males than in females. In addition, in later stages, their sexual dimorphic expressions were maintained in spite of reduced expression. Time-lapse imaging of DapmaFtz-F1 RNAi embryos was performed in H2B-GFP expressing transgenic Daphnia, demonstrating that development of the RNAi embryos slowed down after the gastrulation stage and stopped at 30-48 h after ovulation. DapmaFtz-F1 shows high homology to insect Ftz-F1 orthologs based on its amino acid sequence and exon-intron organization. The sexually dimorphic expression of DapmaFtz-F1 suggests that it plays a role in environmental sex determination of D. magna.
Mohamad Ishak, Nur Syafiqah; Kato, Yasuhiko; Matsuura, Tomoaki; Watanabe, Hajime
Identifying the genes required for environmental sex determination is important for understanding the evolution of diverse sex determination mechanisms in animals. Orthologs of Drosophila orphan receptor Fushi tarazu factor-1 (Ftz-F1) are known to function in genetic sex determination. In contrast, their roles in environmental sex determination remain unknown. In this study, we have cloned and characterized the Ftz-F1 ortholog in the branchiopod crustacean Daphnia magna, which produces males in response to environmental stimuli. Similar to that observed in Drosophila, D. magna Ftz-F1 (DapmaFtz-F1) produces two splicing variants, αFtz-F1 and βFtz-F1, which encode 699 and 777 amino acids, respectively. Both isoforms share a DNA-binding domain, a ligand-binding domain, and an AF-2 activation domain and differ only at the A/B domain. The phylogenetic position and genomic structure of DapmaFtz-F1 suggested that this gene has diverged from an ancestral gene common to branchiopod crustacean and insect Ftz-F1 genes. qRT-PCR showed that at the one cell and gastrulation stages, both DapmaFtz-F1 isoforms are two-fold more abundant in males than in females. In addition, in later stages, their sexual dimorphic expressions were maintained in spite of reduced expression. Time-lapse imaging of DapmaFtz-F1 RNAi embryos was performed in H2B-GFP expressing transgenic Daphnia, demonstrating that development of the RNAi embryos slowed down after the gastrulation stage and stopped at 30–48 h after ovulation. DapmaFtz-F1 shows high homology to insect Ftz-F1 orthologs based on its amino acid sequence and exon-intron organization. The sexually dimorphic expression of DapmaFtz-F1 suggests that it plays a role in environmental sex determination of D. magna. PMID:27138373
Wong, Yue Him
The most recent phylogenomic study suggested that Bryozoa (Ectoprocta), Brachiopoda, and Phoronida are monophyletic, implying that the lophophore of bryozoans, phoronids and brachiopods is a synapomorphy. Understanding the molecular mechanisms of the lophophore development of the Lophophorata clade can therefore provide us a new insight into the formation of the diverse morphological traits in metazoans. In the present study, we profiled the transcriptome of the Bryozoan (Ectoproct) Bugula neritina during the swimming larval stage (SW) and the early (4 h) and late (24 h) metamorphic stages using the Illumina HiSeq2000 platform. Various genes that function in development, the immune response and neurogenesis showed differential expression levels during metamorphosis. In situ hybridization of 23 genes that participate in the Wnt, BMP, Notch, and Hedgehog signaling pathways revealed their regulatory roles in the development of the lophophore and the ancestrula digestive tract. Our findings support the hypothesis that developmental precursors of the lophophore and the ancestrula digestive tract are pre-patterned by the differential expression of key developmental genes according to their fate. This study provides a foundation to better understand the developmental divergence and/or convergence among developmental precursors of the lophophore of bryozoans, branchiopods and phoronids.
Blaxter Mark L
Full Text Available Abstract Background Branchiopod crustaceans in the genus Daphnia are key model organisms for investigating interactions between genes and the environment. One major theme of research on Daphnia species has been the evolution of resistance to pathogens and parasites, but lack of knowledge of the Daphnia immune system has limited the study of immune responses. Here we provide a survey of the immune-related genome of D. pulex, derived from the newly completed genome sequence. Genes likely to be involved in innate immune responses were identified by comparison to homologues from other arthropods. For each candidate, the gene model was refined, and we conducted an analysis of sequence divergence from homologues from other taxa. Results and conclusion We found that some immune pathways, in particular the TOLL pathway, are fairly well conserved between insects and Daphnia, while other elements, in particular antimicrobial peptides, could not be recovered from the genome sequence. We also found considerable variation in gene family copy number when comparing Daphnia to insects and present phylogenetic analyses to shed light on the evolution of a range of conserved immune gene families.
Wong, Yue Him; Ryu, Taewoo; Seridi, Loqmane; Ghosheh, Yanal; Bougouffa, Salim; Qian, Pei-Yuan; Ravasi, Timothy
The most recent phylogenomic study suggested that Bryozoa (Ectoprocta), Brachiopoda, and Phoronida are monophyletic, implying that the lophophore of bryozoans, phoronids and brachiopods is a synapomorphy. Understanding the molecular mechanisms of the lophophore development of the Lophophorata clade can therefore provide us a new insight into the formation of the diverse morphological traits in metazoans. In the present study, we profiled the transcriptome of the Bryozoan (Ectoproct) Bugula neritina during the swimming larval stage (SW) and the early (4 h) and late (24 h) metamorphic stages using the Illumina HiSeq2000 platform. Various genes that function in development, the immune response and neurogenesis showed differential expression levels during metamorphosis. In situ hybridization of 23 genes that participate in the Wnt, BMP, Notch, and Hedgehog signaling pathways revealed their regulatory roles in the development of the lophophore and the ancestrula digestive tract. Our findings support the hypothesis that developmental precursors of the lophophore and the ancestrula digestive tract are pre-patterned by the differential expression of key developmental genes according to their fate. This study provides a foundation to better understand the developmental divergence and/or convergence among developmental precursors of the lophophore of bryozoans, branchiopods and phoronids. PMID:25300304
Sun, Ming'an; Shen, Xin; Liu, Huilian; Liu, Xixing; Wu, Zhigang; Liu, Bin
Mitochondrial genomes play a significant role in the reconstruction of phylogenetic relationships within metazoans. There are still many controversies concerning the phylogenetic position of the phylum Bryozoa. In this research, we have finished the complete mitochondrial genome of one bryozoan (Tubulipora flabellaris), which is the first representative from the class Stenolaemata. The complete mitochondrial genome of T. flabellaris is 13,763bp in length and contains 36 genes, which lacks the atp8 gene in contrast to the typical metazoan mitochondrial genomes. Gene arrangement comparisons indicate that the mitochondrial genome of T. flabellaris has unique gene order when compared with other metazoans. The four known bryozoans complete mitochondrial genomes also have very different gene arrangements, indicates that bryozoan mitochondrial genomes have experienced drastic rearrangements. To investigate the phylogenetic relationship of Bryozoa, phylogenetic analyses based on amino acid sequences of 11 protein coding genes (excluding atp6 and atp8) from 26 metazoan complete mitochondrial genomes were made utilizing Maximum Likelihood (ML) and Bayesian methods, respectively. The results indicate the monopoly of Lophotrochozoa and a close relationship between Chaetognatha and Bryozoa. However, more evidences are needed to clarify the relationship between two groups. Lophophorate appeared to be polyphyletic according to our analyses. Meanwhile, neither analysis supports close relationship between Branchiopod and Phoronida. Four bryozoans form a clade and the relationship among them is T. flabellaris+(F. hispida+(B. neritina+W. subtorquata)), which is in coincidence with traditional classification system. PMID:21867967
Walsh, E.; Gill, T. E.; Rivas, J. A., Jr.; Leung, M. Y.; Mohl, J.
A growing number of studies mark the role of wind in dispersing biota. Most of these approaches have used traditional methods to assess taxonomic diversity. Here we used next generation sequencing to characterize microbiota in dust collected from the Chihuahuan Desert. Atmospheric dust was collected during events during 2011-2014 using dry deposition collectors placed at two sites in El Paso Co., TX. In parallel experiments, we rehydrated subsamples of dust and conducted PCR amplifications using conserved primers for 16S and 18S ribosomal genes. Sequenced reads were de-multiplexed, quality filtered, and processed using QIIME. Taxonomy was assigned based on pairwise identity using BLAST for microbial eukaryotes. All samples were rarefied to a set number of sequences per sample prior to downstream analyses. Bioinformatic analysis of four of the dust samples yielded a diversity of biota, including zooplankton, bacteria, fungi, algae, and protists, but fungi predominate (>90% of both 10K and 3K reads). In our rehydrations of dust samples from the U.S. southwest nematodes, gastrotrichs, tardigrades, monogonont and bdelloid rotifers, branchiopods and numerous ciliates have been recovered. Variability in genetic diversity among samples is based, in part, on the source and extent of the particular dust event. We anticipate the same patterns will be seen in the complete data set. These preliminary results indicate that wind is a major transporter of not only fungi, bacteria and other unicellular organisms but may also be important in shaping the distribution patterns of multi-cellular organisms such as those that inhabit aquatic environments in the arid southwestern US.
Strausfeld, Nicholas J; Andrew, David R
Traditional hypotheses regarding the relationships of the major arthropod lineages focus on suites of comparable characters, often those that address features of the exoskeleton. However, because of the enormous morphological variety among arthropods, external characters may lead to ambiguities of interpretation and definition, particularly when species have undergone evolutionary simplification and reversal. Here we present the results of a cladistic analysis using morphological characters associated with brains and central nervous systems, based on the evidence that cerebral organization is generally robust over geological time. Well-resolved, strongly supported phylogenies were obtained from a neuromorphological character set representing a variety of discrete neuroanatomical traits. Phylogenetic hypotheses from this analysis support many accepted relationships, including monophyletic Chelicerata, Myriapoda, and Hexapoda, paraphyletic Crustacea and the union of Hexapoda and Crustacea (Tetraconata). They also support Mandibulata (Myriapoda + Tetraconata). One problematic result, which can be explained by symplesiomorphies that are likely to have evolved in deep time, is the inability to resolve Onychophora as a taxon distinct from Arthropoda. Crucially, neuronal cladistics supports the heterodox conclusion that both Hexapoda and Malacostraca are derived from a common ancestor that possessed a suite of discrete neural centers comprising an elaborate brain. Remipedes and copepods, both resolved as basal to Branchiopoda share a neural ground pattern with Malacostraca. These findings distinguish Hexapoda (Insecta) from Branchiopoda, which is the sister group of the clade Malacostraca + Hexapoda. The present study resolves branchiopod crustaceans as descendents of an ancestor with a complex brain, which means that they have evolved secondary simplification and the loss or reduction of numerous neural systems. PMID:21333750
Full Text Available Studying the species distribution of Limnadiidae, a family of crustaceans, in environments favourable to their growth and reproduction is made difficult by their extremely short life cycle and the transient existence of adult forms. However, the eggs of these branchiopods are highly resistant to environmental extremes and persist in the soil of humidified and dried pools. We therefore studied the capacity to detect populations of Limnadiidae and identify them at the species level using egg morphology. We investigated influences of pool sediments on Eulimnadia (clam shrimp egg morphology and asked whether we could rely on this morphology after various lengths of time in the soil to recognise species. We studied sediment collected from temporary pools in four Neotropical areas: Minas Gerais and Bahia (Brazil, French Guiana, and Martinique. These samples represented diverse geographical regions and climates and allowed us to study the four most widely distributed Eulimnadia species in the Neotropics: E. colombiensis, E. cylindrova, E. geayi, and E. magdalensis. Our results indicated that soil abrasion is superficial and does not affect the general shape of the eggs (cylindrical or spherical. However, details of egg ornamentation can be severely affected by the combined effects of erosion and filling with sediments, which can lead to difficulties in species identification. In the particular case of the spherical eggs of E. magdalensis, this species cannot be unequivocally identified without clean eggs collected from adults after breeding or from eggs recently deposited in the field. This work and the investigative methods described herein should facilitate identification of Eulimnadia species and promote further study of Limnadiidae crustaceans in the field.
Full Text Available Abstract Background Arthropods are the most diverse animal phylum, but their genomic resources are relatively few. While the genome of the branchiopod Daphnia pulex is now available, no other large-scale crustacean genomic resources are available for comparison. In particular, genomic resources are lacking for the most tractable laboratory model of crustacean development, the amphipod Parhyale hawaiensis. Insight into shared and divergent characters of crustacean genomes will facilitate interpretation of future developmental, biomedical, and ecological research using crustacean models. Results To generate a transcriptome enriched for maternally provided and zygotically transcribed developmental genes, we created cDNA from ovaries and embryos of P. hawaiensis. Using 454 pyrosequencing, we sequenced over 1.1 billion bases of this cDNA, and assembled them de novo to create, to our knowledge, the second largest crustacean genomic resource to date. We found an unusually high proportion of C2H2 zinc finger-containing transcripts, as has also been reported for the genome of the pea aphid Acyrthosiphon pisum. Consistent with previous reports, we detected trans-spliced transcripts, but found that they did not noticeably impact transcriptome assembly. Our assembly products yielded 19,067 unique BLAST hits against nr (E-value cutoff e-10. These included over 400 predicted transcripts with significant similarity to D. pulex sequences but not to sequences of any other animal. Annotation of several hundred genes revealed P. hawaiensis homologues of genes involved in development, gametogenesis, and a majority of the members of six major conserved metazoan signaling pathways. Conclusions The amphipod P. hawaiensis has higher transcript complexity than known insect transcriptomes, and trans-splicing does not appear to be a major contributor to this complexity. We discuss the importance of a reliable comparative genomic framework within which to consider findings
The Notostraca is a small ancient crustacean order dating back to the Carboniferous and possibly up to the Devonian period. In fact, there are Upper Triassic Triops fossils from Germany which are almost indistinguishable from the present Triops cancriformis and thus Triops is considered to be one of the best examples of evolutionary stasis or `living fossil'. Fossil records have shown that the occurrence of Triops is linked to strata resulting from inland freshwater bodies with alternating phases of flooding and drying out. Still today Notostraca species are known from ephemeral ponds and puddles throughout the world. Several Large Branchiopod species such as the European T. cancriformis present adaptations to desiccation, the main one being the production of thick-walled resting cysts. A high number of resting cysts is laid during the flooded period into the pond sediment or is fixed on plants during the adulthood. The drought resistant portion of cysts undergoes an extreme form of diapause. During this resting time the embryo is protected by different (cement)-layers against desiccation, UV-radiation and pressure. Thus their life cycle is perfectly adapted to extreme environments which resulted in the survival of more than 200 Million years. Among the Notostraca a wide range of reproductive modes are present including bisexual -the putatively ancestral state -, androdioecious and hermaphrodite populations. As hermaphroditism and androdioecy confer a colonisation advantage, Triops are suitable for populating experiments whatsoever. Triops is an ideal model organism due to their easy culture and breeding in the lab. Without any impact on the hatching success the resting cysts can easily be extracted from the soil and prepared for controlled experiments. Furthermore their biology has been studied in depth and optimal breeding conditions are known. The ancient group "travelled" successfully through time and is now ready for experiments in the outer space. At the
Gill, T. E.; Walsh, E. J.; Wallace, R. L.; Rojo, L.; Rivas, J. A.
Playas and other ephemeral desert wetlands are preferential terrestrial landforms for dust emission. These sites also are habitat for a diverse assemblage of minute invertebrates. When wetlands desiccate, these invertebrates survive as resting stages (propagules). Thus, playas serve as isolated, ephemeral, biogeographical islands for aquatic invertebrates, but it is unclear how propagules disperse across distances as far as hundreds of kilometers to colonize hydrologically disconnected basins. Aeolian transport (anemochory) may provide the mechanism, especially since many invertebrate propagules are long-lived, aerodynamically shaped, possess low-density, and their size (30-600 μm) falls within the same texture as aeolian dust and sand grains. We are collecting and culturing wind-transported sediment to document its ability to serve in the dispersal of aridland invertebrate propagules. Deposited aeolian sediment was collected from marble-type traps placed on the roof of the Biological Sciences Building at the University of Texas, El Paso, during 19 individual regional-scale Chihuahuan Desert blowing dust/sand events between April 2010 and May 2012. Known source areas for these dust events include playas and ephemeral streams ~40- 150 km upwind. The mean dry grain size of the deposited sediment for each event ranged from 66 to 141 μm. Clean-water rinses of material from each event or standard rehydrations for culturing invertebrates were monitored microscopically for the appearance of organisms. Invertebrates hatched from the sediment of 13 events. Ciliates were detected in each of those samples: gastrotrichs appeared in three samples, nematodes and bdelloid rotifers in two samples, and clam shrimp in one. We have also rehydrated aeolian sediments, collected in standard dust traps, from many dust-emitting playas in Southwest North America and hatched viable organisms including all those previously mentioned as well as branchiopods, fairy shrimp, copepods
Suzuki, Masataka G; Tochigi, Mayuko; Sakaguchi, Honami; Aoki, Fugaku; Miyamoto, Norio
The transformer (tra) gene is an intermediate component of the sex determination hierarchy in many insect species. The homolog of tra is also found in two branchiopod crustacean species but is not known outside arthropods. We have isolated a tra homolog in the acorn worm, Saccoglossus kowalevskii, which is a hemichordate belonging to the deuterostome superphylum. The full-length complementary DNA (cDNA) of the S. kowalevskii tra homolog (Sktra) has a 3786-bp open reading frame that encodes a 1261-amino acid sequence including a TRA-CAM domain and an arginine/serine (RS)-rich domain, both of which are characteristic of TRA orthologs. Reverse transcription PCR (RT-PCR) analyses demonstrated that Sktra showed no differences in expression patterns between testes and ovaries, but its expression level was approximately 7.5-fold higher in the testes than in the ovaries. TRA, together with the protein product of the transformer-2 (tra-2) gene, assembles on doublesex (dsx) pre-messenger RNA (mRNA) via the cis-regulatory element, enhancing female-specific splicing of dsx in Drosophila. To understand functional conservation of the SkTRA protein as a dsx-splicing activator, we investigated whether SkTRA is capable of inducing female-specific splicing of the Drosophila dsx. Ectopic expression of Sktra cDNA in insect cultured cells did not induce the female-specific splicing of dsx. On the other hand, forced expression of Sktra-2 (a tra-2 homolog of S. kowalevskii) was able to induce the female-specific dsx splicing. These results demonstrate that the function as a dsx-splicing activator is not conserved in SkTRA even though SkTRA-2 is capable of functionally replacing the Drosophila TRA-2. We have also found a tra homolog in an echinoderm genome. This study provides the first evidence that that tra is conserved not only in arthropods but also in basal species of deuterostoms. PMID:25868907
Full Text Available L'approvisionnement quotidien en nourriture est, en règle générale, le principal facteur limitant de productions à grande échelle de jeunes poissons marins.La pêche de plancton dans la nature a été, et reste, le moyen d'expérimentation le plus immédiat, et le plus satisfaisant sur le plan qualitatif. Mais la récolte des quantités nécessaires, au moment voulu, devient très délicate dès que l'on dépasse l'échelle de l'aquarium. Le développement, ces dernières décennies, de techniques de production en masse d'animaux-proies a permis le lancement d'élevages à grande échelle. Parmi ces proies, le Branchiopode Artemia salina et le Rotifère Brachionus plicatilis dominent incontestablement ; tandis que l'élevage des Copépodes, part la plus intéressante du plancton naturel, reste encore mal maîtrisé. Cependant , l'élevage et l'emploi de proies vivantes, quelles qu'elles soient, imposent la réalisation d'installations coûteuses et l'emploi d'un abondant personnel qualifié. Il en est résulté récemment un important effort de recherche en direction de nourritures inertes, broyats , poudres et aliments composés, généralement abandonnés après les échecs enregistrés pendant les premières années du siècle. Quelques résultats encourageants ont été obtenus, mais ils restent limités et soulèvent de délicats problèmes d'hygiène des bacs d'élevage. L'emploi de proies vivantes , au moins pendant le premier mois des élevages , reste donc encore une obligation. Dans ce contexte, l'essentiel de l'effort actuel tend , d'une part à réduire leur durée d'emploi au minimum possible et, d'autre part, à rendre leur production plus rationnelle , en recherchant des méthodes qui évitent, pour leur alimentation , de faire appel à des algues planctoniques vivantes.
Full Text Available . A revised classification of Malacostraca based on a phylogenetic analysis is presented. For this purpose 68 morphological characters were cladistically treated using the parsimony programme Paup 4.10. The system here proposed is a reflection of the cladistic tree produced by TABACARU & DANIELOPOL (2011. The following aspects are in the present contribution developed: (1 We consider, in accordance with a widely held opinion of carcinologists, that Phyllocarida (Ord. Leptostraca displays essential synapomorphies with Malacostraca, namely tagmosis 5+7+8+telson, fixation of the gonopore on the 6th female thoracic-segment and on the 8th male-thoracic segment. Based on this assertion Phyllocarida belongs to the Class Malacostraca. Hence we do not share either the ancient view of H. MILNE EDWARDS (1840, who included Nebalia into the Ordo Phyllopodes, Legio Branchiopodes Latreille, or the more recent opinions of SCHRAM (1986, WHEELER (1997 and WILLS (1998 who consider Phyllocarida as belonging to Phyllopoda; (2 the Class Malacostraca is dichotomously separated into Subclasses, Phyllocarida and Eumalacostraca. This is due to the fact that Hoplocarida shares essential synapomorphies with the Eumalacostraca, namely loss of 7th somite of the pleon, thoracic endopod built as stenopod and pleopods of the 6th somite of pleon differentiated as uropods. This opinion is in contradiction with those of other carcinologists who, presupposing a distinct origin of Hoplocarida, consider the Class Malacostraca separated in three Subclasses: Phyllocarida, Hoplocarida and Eumalacostraca (SCHRAM, 1978, 1981; MCLAUGHLIN, 1980; BOWMAN & ABELE, 1982; KUNZE, 1983; DAHL, 1983; AHYONG, 1997; MARTIN & DAVIS, 2001; WELLS & HOUSTON, 2002; FOREST, 2004 ; (3 in our opinion the Superorder Syncarida Packard, 1885 (including the orders Bathynellacea Chappuis, 1915 and Anaspidacea Calman, 1904 does not represent a monophyllum. We accept the view of SERBAN (1972 following which