Envenomation by neotropical Opisthoglyphous colubrid Thamnodynastes cf. pallidus Linné, 1758 (Serpentes:Colubridae in Venezuela Envenenamiento por la colubrida opistoglifa Thamnodynastes cf. pallidus Linné, 1758 (Serpentes:Colubridae en Venezuela
Full Text Available This is a case report of a "non-venomous" snake bite in a herpetologist observed at the Sciences Faculty of the Universidad de los Andes (Mérida, Venezuela. The patient was bitten on the middle finger of the left hand, and shows signs of pronounced local manifestations of envenomation such as bleeding from the tooth imprint, swelling and warmth. He was treated with local care, analgesics, and steroids. He was dismissed from the hospital and observed at home during five days with marked improvement of envenomation. The snake was brought to the medical consult and identified as a Thamnodynastes cf. pallidus specimen. This report represents the first T. pallidus accident described in a human.Se reporta un caso de una mordedura de serpiente "no venenosa", en un herpetólogo observado en la Facultad de Ciencias de la Universidad de los Andes (Mérida, Venezuela. El paciente fue mordido en el dedo medio de la mano izquierda, mostrando pronunciados signos locales de sangramiento por la impronta ocasionada por los dientes de la serpiente, edema y calor local. El paciente fue tratado con cuidados locales, analgésicos y esteroides. Fue dado de alta del hospital y observado en el hogar durante 5 días, con marcada mejoría del envenenamiento. La serpiente fue traída a la consulta médica e identificada como un espécimen de Thamnodynastes cf. pallidus. Este es el primer caso humano descrito, ocasionado por un T. pallidus.
Full Text Available Several colubrid snakes produce venomous oral secretions. In this work, the venom collected from Venezuelan opisthoglyphous (rear-fanged Philodryas olfersii snake was studied. Different proteins were present in its venom and they were characterized by 20% SDS-PAGE protein electrophoresis. The secretion exhibited proteolytic (gelatinase activity, which was partially purified on a chromatography ionic exchange mono Q2 column. Additionally, the haemorrhagic activity of Philodryas olfersii venom on chicken embryos, mouse skin and peritoneum was demonstrated. Neurotoxic symptoms were demonstrated in mice inoculated with Philodryas olfersii venom. In conclusion, Philodryas olfersii venom showed proteolytic, haemorrhagic, and neurotoxic activities, thus increasing the interest in the high toxic action of Philodryas venom.Várias serpentes da família Colubridae produzem secreções orais venenosas. Neste trabalho, foi estudado o veneno coletado da presa posterior da serpente opistóglifa venezuelana Philodryas olfersii. Deferentes proteínas estavam presentes no veneno, sendo caracterizadas pela eletroforese de proteínas (SDS-PAGE a 20%. A secreção mostrou atividade proteolítica (gelatinase a qual foi parcialmente purificada em uma coluna de intercâmbio iônico (mono Q2. Adicionalmente, a atividade hemorrágica do veneno de Philodryas olfersii foi demonstrada em embriões de galinha, pele e peritônio de rato. Os sintomas neurológicos foram demonstrados em camundongos inoculados com veneno de Philodryas olfersii. Em conclusão, o veneno da Philodryas olfersii mostrou atividade proteolítica, hemorrágica, e neurotóxica, assim aumentando o interesse na elevada ação tóxica do veneno da Philodryas olfersii.
Junqueira-de-Azevedo, Inácio L M; Campos, Pollyanna F; Ching, Ana T C; Mackessy, Stephen P
Snake venoms have been subjected to increasingly sensitive analyses for well over 100 years, but most research has been restricted to front-fanged snakes, which actually represent a relatively small proportion of extant species of advanced snakes. Because rear-fanged snakes are a diverse and distinct radiation of the advanced snakes, understanding venom composition among "colubrids" is critical to understanding the evolution of venom among snakes. Here we review the state of knowledge concerning rear-fanged snake venom composition, emphasizing those toxins for which protein or transcript sequences are available. We have also added new transcriptome-based data on venoms of three species of rear-fanged snakes. Based on this compilation, it is apparent that several components, including cysteine-rich secretory proteins (CRiSPs), C-type lectins (CTLs), CTLs-like proteins and snake venom metalloproteinases (SVMPs), are broadly distributed among "colubrid" venoms, while others, notably three-finger toxins (3FTxs), appear nearly restricted to the Colubridae (sensu stricto). Some putative new toxins, such as snake venom matrix metalloproteinases, are in fact present in several colubrid venoms, while others are only transcribed, at lower levels. This work provides insights into the evolution of these toxin classes, but because only a small number of species have been explored, generalizations are still rather limited. It is likely that new venom protein families await discovery, particularly among those species with highly specialized diets.
Francisco L. Franco
Full Text Available Thamnodynastes almae sp. nov. is described based on three specimens from Rodelas municipality, state of Bahia, Northeastern Brazil. The new species can be diagnosed by its pale coloration and keeled dorsal scales arranged in 19 rows at midbody and 15 rows posteriorly. Characters for distinguishing T. almae from other brazilian species of Thamnodynastes are provided.
Meik, Jesse M; Makowsky, Robert
We expand a framework for estimating minimum area thresholds to elaborate biogeographic patterns between two groups of snakes (rattlesnakes and colubrid snakes) on islands in the western Gulf of California, Mexico. The minimum area thresholds for supporting single species versus coexistence of two or more species relate to hypotheses of the relative importance of energetic efficiency and competitive interactions within groups, respectively. We used ordinal logistic regression probability functions to estimate minimum area thresholds after evaluating the influence of island area, isolation, and age on rattlesnake and colubrid occupancy patterns across 83 islands. Minimum area thresholds for islands supporting one species were nearly identical for rattlesnakes and colubrids (~1.7 km 2 ), suggesting that selective tradeoffs for distinctive life history traits between rattlesnakes and colubrids did not result in any clear advantage of one life history strategy over the other on islands. However, the minimum area threshold for supporting two or more species of rattlesnakes (37.1 km 2 ) was over five times greater than it was for supporting two or more species of colubrids (6.7 km 2 ). The great differences between rattlesnakes and colubrids in minimum area required to support more than one species imply that for islands in the Gulf of California relative extinction risks are higher for coexistence of multiple species of rattlesnakes and that competition within and between species of rattlesnakes is likely much more intense than it is within and between species of colubrids.
Weldon, P J; Schell, F M
Four litters of king snakes (Lampropeltis getulus), a snake-eating species, were tested for responses to chemicals from colubrid and crotaline snakes. King snakes presented with swabs rubbed against the dorsal skin of living snakes and with swabs treated with methylene chloride extracts of shed snake skins tongue-flicked more to swabs from a northern copperhead (Agkistrodon contortrix), a crotaline, than to swabs from some colubrid snakes or to blank swabs. Six out of 10 king snakes in one litter attacked and attempted to ingest swabs treated with snake skin chemicals, implicating these chemicals as feeding stimuli for these ophiophagous snakes. Ingestively naive king snakes presented with plain air and snake odors in an olfactometer tongue-flicked more to snake odors. This study and others suggest that crotaline and colubrid snakes can be distinguished by chemical cues.
Henderson, Robert W
Approximately 1590 Hispaniolan colubrid snakes representing six genera and eight species were examined for prey remains (Alsophis cantherigerus, Antillophis parvifrons, Darlingtonia haetiana, Hypsirhynchus ferox, Ialtris dorsalis, Uromacer catesbyi, U. frenatus, and U. oxyrhynchus). The snakes were collected at many localities over a span of 80 years.Of 426 prey items, 77.9% were lizards (of which 69.6% were anoles), 19% frogs, 2.6% birds and mammals, and 0.5% other snakes. Darlingtonia was the only snake that did not exploit lizards; it fed exclusively on Eleutherodactylus frogs, including egg clutches. Disregarding Darlingtonia, there is no size class of Hispaniolan colubrids between 20-90 cm SVL that does not prey primarily on Anolis. Certain prey genera are added to, or deleted from, diets depending on snake size, but the data suggest that snake SVL alone does little to dictate what prey genera (or groups) are eaten. Shannon-Wiener values (H') indicate that Darlingtonia has the narrowest trophic niche, while Alsophis and Ialtris have the widest. Values of H' are not correlated with snake SVL, but highly significant (Peats diurnally active (anoles) and diurnally quiescent (hylid frogs) prey with almost equal frequency.Within Maglio's cantherigerus species assemblage, in which an Alsophis cantherigerus-like snake was ancestral to the other species, and in which longsnouted Uromacer are the most morphologically derived, there is an obvious trend toward trophic specialization on Hispaniola. The West Indies have provided an ideal natural laboratory for the investigation of many aspects of vertebrate ecology, and an arena in which to test theories of island biogeography. The most extensively studied West Indian vertebrates have been the lizards of the iguanid genus Anolis. Conversely, the ecology of West Indian snakes has been largely ignored. This is surprising in light of the fact that much has been written about Anolis predation, but little has been written about
Campos, Pollyanna Fernandes; Andrade-Silva, Débora; Zelanis, André; Paes Leme, Adriana Franco; Rocha, Marisa Maria Teixeira; Menezes, Milene Cristina; Serrano, Solange M T; Junqueira-de-Azevedo, Inácio de Loiola Meirelles
Only few studies on snake venoms were dedicated to deeply characterize the toxin secretion of animals from the Colubridae family, despite the fact that they represent the majority of snake diversity. As a consequence, some evolutionary trends observed in venom proteins that underpinned the evolutionary histories of snake toxins were based on data from a minor parcel of the clade. Here, we investigated the proteins of the totally unknown venom from Phalotris mertensi (Dipsadinae subfamily), in order to obtain a detailed profile of its toxins and to appreciate evolutionary tendencies occurring in colubrid venoms. By means of integrated omics and functional approaches, including RNAseq, Sanger sequencing, high-resolution proteomics, recombinant protein production, and enzymatic tests, we verified an active toxic secretion containing up to 21 types of proteins. A high content of Kunitz-type proteins and C-type lectins were observed, although several enzymatic components such as metalloproteinases and an L-amino acid oxidase were also present in the venom. Interestingly, an arguable venom component of other species was demonstrated as a true venom protein and named svLIPA (snake venom acid lipase). This finding indicates the importance of checking the actual protein occurrence across species before rejecting genes suggested to code for toxins, which are relevant for the discussion about the early evolution of reptile venoms. Moreover, trends in the evolution of some toxin classes, such as simplification of metalloproteinases and rearrangements of Kunitz and Wap domains, parallel similar phenomena observed in other venomous snake families and provide a broader picture of toxin evolution. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
A survey on some biochemical and pharmacological activities of venom from two Colombian colubrid snakes, Erythrolamprus bizona (Double-banded coral snake mimic) and Pseudoboa neuwiedii (Neuwied's false boa).
Torres-Bonilla, Kristian A; Floriano, Rafael S; Schezaro-Ramos, Raphael; Rodrigues-Simioni, Léa; da Cruz-Höfling, Maria Alice
Colombian colubrid snake venoms have been poorly studied. They represent a great resource of biological, ecological, toxinological and pharmacological research. We assessed some enzymatic properties and neuromuscular effects of Erythrolamprus bizona and Pseudoboa neuwiedii venoms from Colombia. Proteolytic, amidolytic and phospholipase A 2 (PLA 2 ) activities were analyzed using colorimetric assays and the neuromuscular activity was analyzed in chick biventer cervicis (BC) preparations. The venom of both species showed very low PLA 2 and amidolytic activities; however, both exhibited high proteolytic activity, which in E. bizona venom surpassed that of P. neuwiedii venom. E. bizona and P. neuwiedii venoms provoked partial neuromuscular blockade, which was more prominent in P. neuwiedii venom. E. bizona venom (30 μg/ml) induced a significant potentiation of the contracture response to exogenous ACh (110 μM), which was not accompanied by twitch height alteration, whereas the highest venom concentration (100 μg/ml) inhibited contracture responses to both ACh and KCl (40 mM). In contrast, P. neuwiedii venom (30 and 100 μg/ml) caused significant reduction in the contracture responses to exogenous ACh and KCl. The morphological analyses showed high myotoxic effects in the muscle fibers of BC incubated with either venoms; however, they are more prominent in the P. neuwiedii venom. Our results suggest that the myotoxicity of the venom of the two Colombian species can be ascribed to their high proteolytic activity. An interesting data was the potentiation of the ACh-induced contracture, but not the twitch height, caused by E. bizona venom, at a concentration that is harmless to muscle fibers integrity. This phenomenon remains to be further elucidated, and suggest that a possible involvement of post-synaptic receptors cannot be discarded. This work is a contribution to expand the knowledge on colubrid venoms; it allows envisaging that the two venoms offer
Non-front-fanged colubroid ("colubrid") snakebites: three cases of local envenoming by the mangrove or ringed cat-eyed snake (Boiga dendrophila; Colubridae, Colubrinae), the Western beaked snake (Rhamphiophis oxyrhynchus; Lamprophiidae, Psammophinae) and the rain forest cat-eyed snake (Leptodeira frenata; Dipsadidae).
Weinstein, S A; Griffin, R; Ismail, A K
Non-front-fanged colubroid snakes (NFFC; formerly and artificially taxonomically assembled as "colubrids") comprise the majority of extant ophidian species. Although the medical risks of bites by a handful of species have been documented, the majority of these snakes have oral products (Duvernoy's secretions, or venoms) with unknown biomedical properties/unverified functions and their potential for causing harm in humans is unknown. Described are three cases of local envenoming from NFFC bites inflicted respectively by the mangrove or ringed cat-eyed snake (Boiga dendrophila, Colubridae), the Western beaked snake (Rhamphiophis oxyrhynchus, Lamprophiidae) and the rain forest cat-eyed snake (Leptodeira frenata, Dipsadidae). The effects ranged from mild pain, edema and erythema to severe pain, progressive edema, and blistering with slowly resolving arthralgia; there were no systemic effects. Although these three taxa occasionally inflict bites with mild to moderate local effects, there is no current evidence of systemic involvement. Two of these cases were reported to one of the authors for medical evaluation, and although verified, thus constitute reliably reported cases, but low-quality evidence. Type-1 local hypersensitivity may contribute to some cases, but most local effects observed or reported in these three cases were consistent with the effects of venom/oral product components.
de Medeiros, Carlos R; Hess, Priscila L; Nicoleti, Alessandra F; Sueiro, Leticia R; Duarte, Marcelo R; de Almeida-Santos, Selma M; França, Francisco O S
We retrospectively analyzed 297 proven cases of Philodryas patagoniensis bites admitted to Hospital Vital Brazil (HVB), Butantan Institute, São Paulo, Brazil, between 1959 and 2008. Only cases in which the causative animal was brought and identified were included. Part of the snakes brought by the patients was still preserved in the collection maintained by the Laboratory of Herpetology. Of the 297 cases, in 199 it was possible to describe the gender of the snake, and seventy three (61.3%) of them were female. The length of snakes (snout-vent length) ranged from 160 to 1080 mm. In 117 snakes their state of preservation enabled the dissection and examination of their stomach contents. The stomach was empty in 106 snakes (89.1%). Most bites occurred in the seasons of spring and summer (n = 196, 66.0%) and during warmer periods of the day. The mean age of the victims was 24.1 +/- 15.1 years old and 206 (69.4%) patients were men. Around 92% of the patients sought medical care within 6 h after the bite. Both lower (n = 188, 63.3%) and upper limbs (n = 102, 34.3%) were most frequently bitten, especially the feet and hands (n = 205, 69.0%). The local clinical manifestations were pain (n = 151, 50.8%), transitory bleeding (n = 106, 35.7%), erythema (n = 47, 15.8%) and edema (n = 39, 13.1%). Ecchymosis was not observed. Only 7 (2.4%) patients reported systemic symptoms characterized by mild dizziness and 88 patients (29.6%) showed no evidence of envenoming. The whole blood clotting time was performed in 76 (25.6%) patients on admission and all of them had coagulable blood. Supportive treatment was offered to only 13.4% of patients, namely administration of antihistamines (n = 19, 6.4%) and analgesics (n = 12, 4.1%). Eight patients (2.7%) were mistreated with Bothrops antivenom before their admission to HVB. No sequels or relevant complications were observed in patients, and the prognostic was benign. Therefore, although P. patagoniensis accidents can cause mild local symptomatology, it is very important that health professionals know how to make the correct diagnosis to avoid unnecessary use of antivenom. (c) 2010 Elsevier Ltd. All rights reserved.
Andrew D. George; Frank R. III Thompson; John. Faaborg
Forecasting the effects of climate change on threatened ecosystems and species will require an understanding of how weather influences processes that drive population dynamics. We have evaluated weather effects on activity patterns of western ratsnakes, a widespread predator of birds and small mammals in eastern North America. From 2010-2013 we radio-tracked 53...
Debono, Jordan; Dobson, James; Casewell, Nicholas R; Romilio, Anthony; Li, Bin; Kurniawan, Nyoman; Mardon, Karine; Weisbecker, Vera; Nouwens, Amanda; Kwok, Hang Fai; Fry, Bryan G
Venoms can deleteriously affect any physiological system reachable by the bloodstream, including directly interfering with the coagulation cascade. Such coagulopathic toxins may be anticoagulants or procoagulants. Snake venoms are unique in their use of procoagulant toxins for predatory purposes. The boomslang ( Dispholidus typus ) and the twig snakes ( Thelotornis species) are iconic African snakes belonging to the family Colubridae. Both species produce strikingly similar lethal procoagulant pathologies. Despite these similarities, antivenom is only produced for treating bites by D. typus , and the mechanisms of action of both venoms have been understudied. In this study, we investigated the venom of D. typus and T. mossambicanus utilising a range of proteomic and bioactivity approaches, including determining the procoagulant properties of both venoms in relation to the human coagulation pathways. In doing so, we developed a novel procoagulant assay, utilising a Stago STA-R Max analyser, to accurately detect real time clotting in plasma at varying concentrations of venom. This approach was used to assess the clotting capabilities of the two venoms both with and without calcium and phospholipid co-factors. We found that T. mossambicanus produced a significantly stronger coagulation response compared to D. typus . Functional enzyme assays showed that T. mossambicanus also exhibited a higher metalloprotease and phospholipase activity but had a much lower serine protease activity relative to D. typus venom. The neutralising capability of the available boomslang antivenom was also investigated on both species, with it being 11.3 times more effective upon D. typus venom than T. mossambicanus . In addition to being a faster clotting venom, T. mossambicanus was revealed to be a much more complex venom composition than D. typus . This is consistent with patterns seen for other snakes with venom complexity linked to dietary complexity. Consistent with the external morphological differences in head shape between the two species, CT and MRI analyses revealed significant internal structural differences in skull architecture and venom gland anatomy. This study increases our understanding of not only the biodiscovery potential of these medically important species but also increases our knowledge of the pathological relationship between venom and the human coagulation cascade.
Savage, J.M.; McDiarmid, R.W.
Sibon argus Cope, 1875, long known only from the holotype, is redescribed based on material from Costa Rica and Panama. It differs from the only other member of the genus having an ocellate dorsal pattern (S. longifrenis) in its attenuate habitus, enlarged blunt head, protuberant eyes, and high segmental counts (ventrals 181-201, subcaudals 112-121, total segmental counts 294-312). Sibon longifrenis of Atlantic slope Costa Rica and western Panama (ventrals 151-173, subcaudals 82-103, total segmental counts 231-275) is also redescribed. These species differ from all other Sibon in having an ocellate pattern and an enlarged penultimate supralabial bordering the orbit. The allied species, S. annulatus (Costa Rica and Panama) and S. dimidiatus (Mexico to southwestern Costa Rica), are shown to be distinct from S. argus and S. longifenis in scalation and coloration. Although allopatric, S. annulatus and S. dimidiatus differ from one another most strikingly in adult coloration, postmental character states, and ventral counts (x = 175.8 in annulatus and 193.6 in dimidiatus), and are regarded as valid species. Sibon annulatus occurs sympatrically with S. argus in Panama and with S. longifrenis in Costa Rica. Although S. argus and S. longifrenis occur in the same general area on the Atlantic slope of Costa Rica, they have not yet been taken at the same locality.
Figueroa, Alex; McKelvy, Alexander D; Grismer, L Lee; Bell, Charles D; Lailvaux, Simon P
With over 3,500 species encompassing a diverse range of morphologies and ecologies, snakes make up 36% of squamate diversity. Despite several attempts at estimating higher-level snake relationships and numerous assessments of generic- or species-level phylogenies, a large-scale species-level phylogeny solely focusing on snakes has not been completed. Here, we provide the largest-yet estimate of the snake tree of life using maximum likelihood on a supermatrix of 1745 taxa (1652 snake species + 7 outgroup taxa) and 9,523 base pairs from 10 loci (5 nuclear, 5 mitochondrial), including previously unsequenced genera (2) and species (61). Increased taxon sampling resulted in a phylogeny with a new higher-level topology and corroborate many lower-level relationships, strengthened by high nodal support values (> 85%) down to the species level (73.69% of nodes). Although the majority of families and subfamilies were strongly supported as monophyletic with > 88% support values, some families and numerous genera were paraphyletic, primarily due to limited taxon and loci sampling leading to a sparse supermatrix and minimal sequence overlap between some closely-related taxa. With all rogue taxa and incertae sedis species eliminated, higher-level relationships and support values remained relatively unchanged, except in five problematic clades. Our analyses resulted in new topologies at higher- and lower-levels; resolved several previous topological issues; established novel paraphyletic affiliations; designated a new subfamily, Ahaetuliinae, for the genera Ahaetulla, Chrysopelea, Dendrelaphis, and Dryophiops; and appointed Hemerophis (Coluber) zebrinus to a new genus, Mopanveldophis. Although we provide insight into some distinguished problematic nodes, at the deeper phylogenetic scale, resolution of these nodes may require sampling of more slowly-evolving nuclear genes.
Javan M Bauder
Full Text Available Understanding the factors influencing the degree of spatial overlap among conspecifics is important for understanding multiple ecological processes. Compared to terrestrial carnivores, relatively little is known about the factors influencing conspecific spatial overlap in snakes, although across snake taxa there appears to be substantial variation in conspecific spatial overlap. In this study, we described conspecific spatial overlap of eastern indigo snakes (Drymarchon couperi in peninsular Florida and examined how conspecific spatial overlap varied by sex and season (breeding season vs. non-breeding season. We calculated multiple indices of spatial overlap using 6- and 3-month utilization distributions (UD of dyads of simultaneously adjacent telemetered snakes. We also measured conspecific UD density values at each telemetry fix and modeled the distribution of those values as a function of overlap type, sex, and season using generalized Pareto distributions. Home range overlap between males and females was significantly greater than overlap between individuals of the same sex and male home ranges often completely contained female home ranges. Male home ranges overlapped little during both seasons, whereas females had higher levels of overlap during the non-breeding season. The spatial patterns observed in our study are consistent with those seen in many mammalian carnivores, in which low male-male overlap and high inter-sexual overlap provides males with greater access to females. We encourage additional research on the influence of prey availability on conspecific spatial overlap in snakes as well as the behavioral mechanisms responsible for maintaining the low levels of overlap we observed.
Full Text Available Venoms can deleteriously affect any physiological system reachable by the bloodstream, including directly interfering with the coagulation cascade. Such coagulopathic toxins may be anticoagulants or procoagulants. Snake venoms are unique in their use of procoagulant toxins for predatory purposes. The boomslang (Dispholidus typus and the twig snakes (Thelotornis species are iconic African snakes belonging to the family Colubridae. Both species produce strikingly similar lethal procoagulant pathologies. Despite these similarities, antivenom is only produced for treating bites by D. typus, and the mechanisms of action of both venoms have been understudied. In this study, we investigated the venom of D. typus and T. mossambicanus utilising a range of proteomic and bioactivity approaches, including determining the procoagulant properties of both venoms in relation to the human coagulation pathways. In doing so, we developed a novel procoagulant assay, utilising a Stago STA-R Max analyser, to accurately detect real time clotting in plasma at varying concentrations of venom. This approach was used to assess the clotting capabilities of the two venoms both with and without calcium and phospholipid co-factors. We found that T. mossambicanus produced a significantly stronger coagulation response compared to D. typus. Functional enzyme assays showed that T. mossambicanus also exhibited a higher metalloprotease and phospholipase activity but had a much lower serine protease activity relative to D. typus venom. The neutralising capability of the available boomslang antivenom was also investigated on both species, with it being 11.3 times more effective upon D. typus venom than T. mossambicanus. In addition to being a faster clotting venom, T. mossambicanus was revealed to be a much more complex venom composition than D. typus. This is consistent with patterns seen for other snakes with venom complexity linked to dietary complexity. Consistent with the external morphological differences in head shape between the two species, CT and MRI analyses revealed significant internal structural differences in skull architecture and venom gland anatomy. This study increases our understanding of not only the biodiscovery potential of these medically important species but also increases our knowledge of the pathological relationship between venom and the human coagulation cascade.
McKelvy, Alexander D.; Grismer, L. Lee; Bell, Charles D.; Lailvaux, Simon P.
Background With over 3,500 species encompassing a diverse range of morphologies and ecologies, snakes make up 36% of squamate diversity. Despite several attempts at estimating higher-level snake relationships and numerous assessments of generic- or species-level phylogenies, a large-scale species-level phylogeny solely focusing on snakes has not been completed. Here, we provide the largest-yet estimate of the snake tree of life using maximum likelihood on a supermatrix of 1745 taxa (1652 snake species + 7 outgroup taxa) and 9,523 base pairs from 10 loci (5 nuclear, 5 mitochondrial), including previously unsequenced genera (2) and species (61). Results Increased taxon sampling resulted in a phylogeny with a new higher-level topology and corroborate many lower-level relationships, strengthened by high nodal support values (> 85%) down to the species level (73.69% of nodes). Although the majority of families and subfamilies were strongly supported as monophyletic with > 88% support values, some families and numerous genera were paraphyletic, primarily due to limited taxon and loci sampling leading to a sparse supermatrix and minimal sequence overlap between some closely-related taxa. With all rogue taxa and incertae sedis species eliminated, higher-level relationships and support values remained relatively unchanged, except in five problematic clades. Conclusion Our analyses resulted in new topologies at higher- and lower-levels; resolved several previous topological issues; established novel paraphyletic affiliations; designated a new subfamily, Ahaetuliinae, for the genera Ahaetulla, Chrysopelea, Dendrelaphis, and Dryophiops; and appointed Hemerophis (Coluber) zebrinus to a new genus, Mopanveldophis. Although we provide insight into some distinguished problematic nodes, at the deeper phylogenetic scale, resolution of these nodes may require sampling of more slowly-evolving nuclear genes. PMID:27603205
D. Craig Rudolph; Shirley J. Burgdorf; Richard N. Conner; Christopher S. Collins; Daniel Saenz; Richard R. Schaefer; Toni Trees; C. Michael Duran; Marc Ealy; John G. Himes
Diet and prey handling behavior were determined for Louisiana pine snakes (Pituophis ruthveni) and black pine snakes (P. melanoleucus lodingi). Louisiana pine snakes prey heavily on Baird's pocket gophers (Geomys breviceps), with which they are sympatric, and exhibit specialized behaviors that facilitate...
Maria Cristina dos SANTOS-COSTA
Full Text Available This is a case report of a Boiruna maculata snake bite in a child admitted to the Hospital Municipal de Pronto Socorro de Porto Alegre, Porto Alegre, RS, Brazil. The patient was bitten on the lower left limb, and exhibited pronounced local manifestations of envenomation. She was treated with Bothrops antivenom and was discharged from the hospital five days later with marked improvement of envenomation.Este trabalho relata o envenenamento por serpente do gênero Boiruna maculata em criança admitida e posteriormente hospitalizada no Hospital Municipal de Pronto Socorro de Porto Alegre, RS, Brasil. A paciente foi mordida no membro inferior esquerdo e apresentou sinais de envenenamento local pronunciado, foi tratada como acidente botrópico e permaneceu no hospital por cinco dias, recebendo alta após melhora.
de Freitas, Marco; Colli, Guarino; Entiauspe-Neto, Omar; Trinchão, Luiz; Araújo, Daniel; Lima, Tiago; de França, Daniella; Gaiga, Renato; Dias, Pedro
We present a list of snake species found in 10 municipalities in the Cerrado of western Bahia state, Brazil. One hundred and twenty individuals of 46 species from seven families were examined. We also present a new state record for the genus Phalotris Cope, 1862 and a candidate new species for the genus Thamnodynastes Wagler, 1830.
Sandra Milena Peñuela
Artículo de opinión: Una mañana, en la que rutinariamente se había programado la alimentación de los ofidios en un “zoológico local”, el herpetólogo encargado del área, se aproximo al encierro de un ejemplar de guardacamino (Thamnodynastes pallidus) y fue sorprendido por una mordida del animal. Este individuo de escasos 30cm no representó ninguna amenaza, que impidiera el normal desarrollo de las actividades del día, aunque un dolor intenso en el dedo afectado lo distraía fácilmente; al cabo ...
Rejane Maria Lira-da-Silva
Full Text Available Great part of lhe avaiable data about snakes reprodution refers to species coming from subtropical and temperate regions. In Brazil, the data is rather rare and can be found in various works where information is restricted. Results from studies developed with five viviparous snakes - Crotalus durissus cascavella (Wagler, 1824. Bothrops erythromelas(Amaral, 1923, B. leucurus (Wagler, 1824, Helicops leopardinus (Schlegel, 1873 and Thamnodynastes strigilis (Thiinberg, 1787 - which come from the Northeast of Brazil (Bahia are described. Data about pregnancy and birth, number, sex ratio, length and weight of neonates is given and discussed.
Introduction Tachymenis is a characteristic genus of colubrid snakes inhabiting extreme western South America, from coastal Peru and Chile east to Bolivia (Walker, 1945; Peters & Orejas-Miranda, 1970). An extralimital species in Brazil, Tachymenis brasiliensis Gomes, was referred to its own genus
Gâz Florea Şerban Andrei; Gâz Florea Adriana; Kelemen Hajnal; Muntean Daniela-Lucia
As more data are generated from proteome and transcriptome analysis revealing that metalloproteinases represent most of the Viperid and Colubrid venom components authors decided to describe in a short review a classification and some of the multiple activities of snake venom metalloproteinases. SVMPs are classified in three major classes (P-I, P-II and P-III classes) based on the presence of various domain structures and according to their domain organization. Furthermore, P-II and P-III clas...
Lemos-Espinal, Julio A.; Smith, Geoffrey R.; Woolrich-Piña, Guillermo A.
Abstract A summary of the species of amphibians and reptiles of the state has been compiled, including their geographic distributions, habitats, and conservation statuses. The herpetofauna of San Luis Potosí consists of 41 species of amphibians and 141 species of reptiles. San Luis Potosí shares the highest number of species with Hidalgo and Tamaulipas, and the least number of species with Nuevo León. In San Luis Potosí, there are several taxa of particular conservation concern including salamanders, emydid and trionychid turtles, anguid and xenosaurid lizards, and natricid and colubrid snakes. PMID:29731682
Full Text Available In this study, we describe two fossil remains of squamate reptiles found in Middle Pleistocene outcrops at the northern marine cliffs of the city of Mar del Plata (Buenos Aires province. The specimens were found forming a taphocenosis with remains of other microvertebrates (amphibians, mammals and birds. The reptiles recognized in the association are represented by remains of an undetermined colubrid, and the anguid Ophiodes sp. This latter finding represents the first fossil record for the family Anguidae exhumed in Argentina.
Full Text Available We describe the courtship behavior of the Paradise Flying Snake, Chrysopelea paradisi, from a series of images taken near Sandakan, eastern Sabah, Borneo, Malaysia. During the episode observed, four males moved together with a female in various states of entanglement, traveling at ground level and into a series of bushes. The observations took place over the course of a 30-min period until the snakes were lost to view. Our report is the first direct observation of mating behavior in C. paradisi in the wild and provides another rare glimpse of the multi-male courtship in Southeast Asian colubrids.
small, potentially evasive target with an impact sufficient for prey capture but without 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13...strike a small, potentially evasive target with an impact sufficient for prey capture but without damaging their lightly-built skull. Although the...p o rt io n o f To ta l M as s Segment Number Boa/Python Mean Colubrid Mean Viper Mean Figure 3 – Proportion of body mass in each of 10 equal-length
Full Text Available Sibon lamari, a new species of colubrid snake from northeastern Costa Rica is described on the basis of six specimens. The new form differs from the closely allied S. annulatus in color pattern, head size, subcaudal count, and number of labials bordering eye-orbit. This is the third species of Sibon, together with S. argus and S. longifrenis, possessing a green dorsal ground color in Costa Rica. Sibon lamari coexists sympatrically with S. annulatus, S. argus, S. longifrenis and S. nebulatus at the locality of Guayacán de Siquirres (Limón Province
Lemos-Espinal, Julio A; Smith, Geoffrey R; Woolrich-Piña, Guillermo A
A summary of the species of amphibians and reptiles of the state has been compiled, including their geographic distributions, habitats, and conservation statuses. The herpetofauna of San Luis Potosí consists of 41 species of amphibians and 141 species of reptiles. San Luis Potosí shares the highest number of species with Hidalgo and Tamaulipas, and the least number of species with Nuevo León. In San Luis Potosí, there are several taxa of particular conservation concern including salamanders, emydid and trionychid turtles, anguid and xenosaurid lizards, and natricid and colubrid snakes.
Francílio da Silva Rodrigues
Full Text Available This study records and analyzes the diversity and structure of a snake assemblage in a transition area between Cerrado and Caatinga, in the municipality of Castelo do Piauí, state of Piauí, comparing the distribution and similarity of the species composition with other open localities already studied in Brazil. We used three complementary sampling methods: time constrained search (TCS, pitfall traps with drift fences (PFT, and incidental encounters (IE. During the TCS and PFT, 912 hours/observer and 6,468 days/trap were used, respectively. We estimated 23 species of snakes for the locality, although only 19 species were recorded. Philodryas nattereri Steindachner, 1870 (n = 10, Liophis poecilogyrus (Schlegel, 1837 (n = 9, Liophis viridis Günther, 1862 (n = 8 and Thamnodynastes sp. (n = 8 were the most abundant species. Terrestrial, cryptozoic, and diurnal snakes predominated in the assemblage (Boidae = 2 species, Dipsadidae = 12, Colubridae = 2, Elapidae = 1, Viperidae = 2. The results indicate that the fauna of the locality is similar with that of other open formations, especially the Caatinga, corroborating previous floristic studies. Comparisons between snake assemblages analyzed by different authors suggest structural differences between the assemblages of the Cerrado and the Caatinga, contradicting the hypothesis of mixed composition of fauna in these biomes.
Full Text Available The reproductive cycles of snakes can be influenced by many factors, both biotic and abiotic, and information about these factors can contribute significantly to knowledge of the biology of many species. Here, we present data on the reproductive biology (body size, sexual dimorphism and female reproductive cycle of the forest-dwelling colubrid Echinanthera cyanopleura (Cope, 1885, based on analyses of 128 specimens preserved in collections and originating from the states of Paraná, Santa Catarina, and Rio Grande do Sul in southern Brazil. The snout-vent length of females was significantly greater than in males. The tail length of mature females was greater than in males, although this difference was not significant. Vitellogenesis occurs from August to December and eggs were found in greater frequency from October through December. Juveniles were found in larger numbers beginning in February, indicating that recruitment occurs from January to April. The reproductive cycle of this species is seasonal, which is usual for oviparous colubrids of temperate areas of Brazil.
Oliveira, Juliana S; Sant'Anna, Luciana B; Oliveira Junior, Manoel C; Souza, Pamella R M; Andrade Souza, Adilson S; Ribeiro, Wellington; Vieira, Rodolfo P; Hyslop, Stephen; Cogo, José C
Envenomation by the South American opisthoglyphous snake Philodryas olfersii causes local pain, edema, erythema and ecchymosis; systemic envenomation is rare. In this work, we examined the inflammatory activity of P. olfersii venom (10, 30 and 60 μg) in mouse gastrocnemius muscle 6 h after venom injection. Intramuscular injection of venom did not affect hematological parameters such as red cell count, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The venom caused thrombocytopenia (at all three doses), leukopenia and lymphopenia (both at the two highest doses), as well as neutrophilia (30 μg), monocytosis (30 μg) and basophilia (10 μg). Of the cytokines that were screened [IL-1β, IL-6, IL-10, IL-13, IL-17, TNF-α, IFN-γ, MIP-2 and KC] and IGF-1, only IGF-1 showed a significant increase in its circulating concentration, seen with 60 μg of venom; there were no significant changes in the cytokines compared to control mice. Histological analysis revealed the presence of edema, an inflammatory infiltrate and progressive myonecrosis. Edema and myonecrosis were greatest with 60 μg of venom, while the inflammatory infiltrate was greatest with 10 μg of venom. All venom doses caused the migration of polymorphonuclear and mononuclear leukocytes into muscle, but with no significant dose-dependence in the response. These findings show that, at the doses tested, P. olfersii venom does not cause hematological alterations and has limited effect on circulating cytokine concentrations. These data also confirm that the principal effects of the venom in mice are local edema, inflammatory cell infiltration and myonecrosis. Copyright © 2017 Elsevier Ltd. All rights reserved.
Gerson Moreira Rodrigues
Full Text Available ABSTRACT We describe the diversity, natural history and structure of snake assemblages from Marajó Island, state of Pará, Brazil, after analyzing 439 specimens deposited in herpetological collections. We tested the hypothesis that snake assemblages from forest and open areas of Marajó Island are distinct with regard to their structure, composition and functional groups. To compare the snake composition of the forest and open areas of Marajó with other comparable assemblages in Brazil, Principal Coordinate Analysis and Clustering tests were performed. A total of 61 species of snakes was recorded for Marajó, with ten species cited for the first time for the study area (Atractus natans Hoogmoed & Prudente, 2003, A. schach (Boie, 1827, Dendrophidion dendrophis (Schlegel, 1837, Helicops hagmanni Roux, 1910, Hydrops martii (Wagler in Spix, 1824, Lygophis meridionalis (Schenkel, 1901, Erythrolamprus typhlus (Linnaeus, 1758, Philodryas argentea (Daudin, 1803, Siphlophis cervinus (Laurenti, 1768, and Thamnodynastes sp.. The composition and structure of snake assemblages between forested and open were different, with five functional groups of snakes in forest areas, and three groups in open areas, based on habit and habitat. In all, 19 species were exclusive to forest areas, 10 were exclusive to open areas and 26 species were recorded in both areas. Our results revealed greater richness for forested areas, probably due to greater habitat heterogeneity. The species composition for forested area in Marajó was similar to that found in other Amazonian assemblages, while that for open areas was more similar to the Pantanal region than other open area assemblages. The general structure of the snake assemblage of Marajó was dominated by anurophagous, terrestrial and diurnal species. Terrestrial, arboreal and semi-arboreal snakes showed a seasonal offspring production pattern, while the pattern for aquatic and semi-aquatic species was aseasonal. The
Lemos-Espinal, Julio A.; Smith, Geoffrey R.; Gadsden-Esparza, Hector; Rosaura Valdez-Lares; Woolrich-Piña, Guillermo A.
Abstract A summary of the species of amphibians and reptiles of Durango, as well as their geographic distributions, habitat, and conservation status have been compiled. The herpetofauna of Durango consists of 36 species of amphibians and 120 species of reptiles. Durango shares the most species with Chihuahua (74.0%), and shares fewer species with Sinaloa (48.0%), Nayarit (48.7%), and Coahuila (48.0%). Arid-semiarid and Sierras habitat types have the most species, with valleys and Quebradas habitat types having fewer species. In Durango, there are several taxa of particular conservation concern including eleutherodactylid frogs, eublepharid, iguanid, phrynosomatid, and xantusid lizards, boid, colubrid, and natricid snakes, and emydid and testudinid turtles. PMID:29674915
Gâz Florea Şerban Andrei
Full Text Available As more data are generated from proteome and transcriptome analysis revealing that metalloproteinases represent most of the Viperid and Colubrid venom components authors decided to describe in a short review a classification and some of the multiple activities of snake venom metalloproteinases. SVMPs are classified in three major classes (P-I, P-II and P-III classes based on the presence of various domain structures and according to their domain organization. Furthermore, P-II and P-III classes were separated in subclasses based on distinctive post-translational modifications. SVMPs are synthesized in a latent form, being activated through a Cys-switch mechanism similar to matrix metalloproteinases. Most of the metalloproteinases of the snake venom are responsible for the hemorrhagic events but also have fibrinogenolytic activity, poses apoptotic activity, activate blood coagulation factor II and X, inhibit platelet aggregation, demonstrating that SVMPs have multiple functions in addition to well-known hemorrhagic function.
Allentoft, Morten; Redsted Rasmussen, Arne; Kristensen, Hans Viborg
Abstract: The Aesculapian snake (Zamenis longissimus) is distributed in Central and Southern Europe, the Balkans, Anatolia, and Iran, but had a wider mid-Holocene distribution into Northern Europe. To investigate the genetic affinity of a Danish population that went extinct in historical times, we...... analysed three ethanol-preserved individuals dating back to 1810 using a silica-in-solution ancient DNA extraction method, combined with next-generation sequencing. Bioinformatic mapping of the reads against the published genome of a related colubrid snake revealed that two of the three specimens contained...... endogenous snake DNA (up to 8.6% of the reads), and this was evident for tooth, bone, and soft tissue samples. The DNA was highly degraded, observed by very short average sequence lengths (
Maria Elisabeth de Araújo
Full Text Available The present paper reports two cases of human envenoming by colubrid snakes of Philodryas, considered as not poisonous, showing evidence of the clinical aspects and the evolution of the symptoms of envenoming. The similarity of these cases with those caused by Bothrops suggests a more careful evaluation on the victims considering the medical treatment to be adopted.O presente trabalho é um relato de dois casos de acidentes com colubrídeos (Philodryas olfersii e P. patagoniensis considerados não peçonhentos, que destaca as manifestações clínicas e as suas evoluções. A semelhança de tais acidentes com aqueles causados por serpentes Bothrops indica a necessidade de uma melhor avaliação dos pacientes quanto à terapêutica a ser adotada.
Biologia reprodutiva da cobra-coral Erythrolamprus aesculapii Linnaeus (Colubridae, no Sudeste do Brasil Reproductive biology of the coral snake Erythrolamprus aesculapii Linnaeus (Colubridae in the Southeastern Brazil
Otávio A.V. Marques
Full Text Available Dissection of 286 specimens of the "false" coral snake Erythrolamprus aesculapii Linnaeus, 1766, combined with data on captive individuais, provided information on the reproductive biology of this colubrid snake. Adult females (x snout-vent length = 74.5cm attain larger body size than males (x SVL = 62.6. Clutch size ranged from one to eight eggs and was correlated with maternal body size. Neonates measured 20.2-22.5cm SVL and weighed 5.1-5.8g. Males attain sexual maturity earlier than females. Reproduction seems to be aseasonal, with vitellogenesis occurring throughout the year. Apparently the growth rate of folheies decreases in the dry season, possibly due to lower tempeiatures during this period. Multiple clutches were recorded in captive snakes. Foraging strategies and availability of prey may explain continuous reproduction in E. aesculapii. However, data for other related snakes suggest that continuous reproduction is conservative in the Xenodontini.
Koch, Claudia; Venegas, Pablo J
A new colubrid species of the genus Tantilla from the dry forest of the northern Peruvian Andes is described on the basis of two specimens, which exhibit a conspicuous sexual dimorphism. Tantilla tjiasmantoi sp. nov. represents the third species of the genus in Peru. The new species is easily distinguished from its congeners by the combination of scalation characteristics and the unusual transversely-banded color pattern on the dorsum. A detailed description of the skull morphology of the new species is given based on micro-computed tomography images. The habitat of this new species is gravely threatened due to human interventions. Conservation efforts are urgently needed in the inter-Andean valley of the Maranon River.
Lemos-Espinal, Julio A; Smith, Geoffrey R; Gadsden-Esparza, Hector; Rosaura Valdez-Lares; Woolrich-Piña, Guillermo A
A summary of the species of amphibians and reptiles of Durango, as well as their geographic distributions, habitat, and conservation status have been compiled. The herpetofauna of Durango consists of 36 species of amphibians and 120 species of reptiles. Durango shares the most species with Chihuahua (74.0%), and shares fewer species with Sinaloa (48.0%), Nayarit (48.7%), and Coahuila (48.0%). Arid-semiarid and Sierras habitat types have the most species, with valleys and Quebradas habitat types having fewer species. In Durango, there are several taxa of particular conservation concern including eleutherodactylid frogs, eublepharid, iguanid, phrynosomatid, and xantusid lizards, boid, colubrid, and natricid snakes, and emydid and testudinid turtles.
Geraldo C. Leynaud
Full Text Available Colubrid snakes of the South American genus Phalotris are difficult to detect because of their secretive habits, and thus they are poorly represented in collections. The species Phalotris cuyanus and P. tricolor, the southernmost representatives of the tricolor species group, were studied to determine the limits of intraspecific variation of P. cuyanus and to consolidate the taxonomic relationship between both species, the phenetically and geographically closest members in the group. The distribution of selected external characters (cephalic, ventral and subcaudal scales, coloration pattern, width of white and black collars, and hemipenis morphology were analyzed. Comparative data on the other members of the group, P. mertensi and P. matogrossensis, are briefly discussed. Males of P. cuyanus have a higher number of ventral scales than males of P. tricolor (mean of 220.3 vs. 204.6. Cephalic melanism varies among individuals and does not have discriminant orgeographic value for this species group. The white nuchal collar may partially cover the parietal scales in the four species. The black collar is moderately narrow in P. cuyanus, but it can be up to 12 scales wide in P. tricolor. Vertebral dotting is neither constant nor exclusive of any species. The four species of the group are wellcharacterized by combinations of character states for each one. We suggest considering to P. cuyanus as an evolutionary species typical of the Monte biogeographic province.
Grismer, L Lee; Quah, Evan S H; Anuar M S, Shahrul; Muin, Mohd Abdul; Wood, Perry L; Nor, Siti Azizah Mohd
A newly discovered, diminutive, cave-dwelling, lowland species of the colubrid snake genus Lycodon Boie is described from a limestone cave along the Thai-Malaysian border in the state of Perlis, northwestern Peninsular Malaysia. Lycodon cavernicolus sp. nov. is most closely related to L. butleri Boulenger, an endemic, upland, forest-dwelling species from Peninsular Malaysia of the fasciatus group but is separated from L. butleri and all other species of the L. fasciatus group and the closely related L. ruhstrati group by having the combination of 245 (male) and 232 (female) ventral scales; 113 (male) and 92 (female) paired, subcaudal scales; a single precloacal plate; nine or 10 supralabials; 10 or 11 infralabials; a maximum total length of 508 mm (female); a relative tail length of 0.25-0.27; an immaculate venter in juveniles and dark-brown, posterior, ventral scale margins in adults; and dorsal and caudal bands in juveniles white. The discovery of L. cavernicolus sp. nov. adds to a rapidly growing list of newly discovered reptiles from karst regions and limestone forests of Peninsular Malaysia, underscoring the fact that these areas should be studied before they are quarried as they harbor a significant portion of the Peninsular Malaysia's herpetological diversity.
Full Text Available Sarcocysts in muscles of the teiid lizard Ameiva ameivafrom north Brazil were fed to the colubrid snake Mastigodryas bifossatus, the faeces of which had been shown to be devoid of coccidial oocysts or sporocysts. When necropsied 16 days later the snake was shown to have developed a massive intestinal infection of Sarcocystis. Mature sporocysts from another, naturally infected M. bifossatus were fed to juvenile specimens of A. ameiva in which no sarcocysts could be detected in tail muscle biopsies. When examined 30 and 47 days later they had very large numbers of sarcocysts in their tail and tongue muscles. The parasite is given the name of Sarcocystis ameivamastigodryasi n. sp. An ultrastructural study has been made of the sarcocyst and of the parasite's sporulation in the lamina propria of the snake: the latter provides details of the wall formation process in developing sporocysts. Attempts to infect a specimen of the boid Boa constrictor constrictor by feeding it with infected Ameivafailed, suggesting that sporocysts previously recorded in genera of the family Boidae may be those of a different species of Sarcocystis.
Muñoz-Gutiérrez, J F; Garner, M M; Kiupel, M
Chromatophoromas are neoplasms arising from pigment-bearing cells (chromatophores) of the dermis. While isolated cases have been reported in the literature, the prevalence and biological behavior of chromatophoromas in snakes are unknown. Forty-two chromatophoromas were identified among 4663 submissions (0.9%) to a private diagnostic laboratory in a 16-year period. The most commonly affected snakes were colubrids (23 cases, 55%) and vipers (8 cases, 19%). The San Francisco garter snake was the most commonly affected species (6 cases; 14% of all affected snake species and 3.7% of all garter snake submissions). No sex predilection was found. The age of 28 snakes ranged from 5 to 27 years. Single cutaneous chromatophoromas were most commonly observed and presented as pigmented cutaneous masses or plaques along any body segment. Euthanasia or death due to progressive neoplastic disease or metastasis was reported in 8 (19%) and 4 (10%) cases, respectively. The survival time of 4 animals ranged from 4 to 36 months. Microscopically, xanthophoromas, iridophoromas, melanocytic neoplasms, and mixed chromatophoromas were identified, with melanocytic neoplasms being most common. Microscopic examination alone was generally sufficient for the diagnosis of chromatophoroma, but immunohistochemistry for S-100 and PNL-2 may be helpful for diagnosing poorly pigmented cases. Moderate to marked nuclear atypia appears to be consistently present in cutaneous chromatophoromas with a high risk of metastasis, while mitotic count, lymphatic invasion, the level of infiltration, and the degree of pigmentation or ulceration were not reliable predictors of metastasis. © The Author(s) 2016.
Full Text Available Snake liver has been implicated in the adaptation of snakes to a variety of habitats. However, to date, there has been no systematic analysis of snake liver proteins. In this study, we undertook a proteomic analysis of liver from the colubrid snake Elaphe taeniura using a combination of two-dimensional electrophoresis (2-DE and matrix-assisted laser desorption/ionization time of flightmass spectrometry (MALDI-TOF MS. We also constructed a local protein sequence database based on transcriptome sequencing to facilitate protein identification. Of the 268 protein spots revealed by 2-DE 109 gave positive MS signals, 84 of which were identified by searching the NCBInr, Swiss-Prot and local databases. The other 25 protein spots could not be identified, possibly because their transcripts were not be stable enough to be detected by transcriptome sequencing. GO analysis showed that most proteins may be involved in binding, catalysis, cellular processes and metabolic processes. Forty-two of the liver proteins identified were found in other reptiles and in amphibians. The findings of this study provide a good reference map of snake liver proteins that will be useful in molecular investigations of snake physiology and adaptation.
Jorge A. L. Pontes
Full Text Available We studied the ecology of ticks found in different species of a taxocenosis of snakes from the Serra do Mendanha, an area of Atlantic Rainforest located in the state of Rio de Janeiro, southeastern Brazil. Snakes were sampled monthly in the field during a period of 48 months. The specific identity of the hosts and their parasites, the number of parasites, and and snout-vent length and body mass of each host were recorded. A total of 25% of the species of snakes in the area were parasitized by ticks (larvae, nymphs and adult females Amblyomma rotundatum Koch, 1844 was the predominant parasite species. The infestation parameters varied among the species of snakes sampled, with the highest prevalence of A. rotundatum being observed in the viperid Bothrops jararaca (Wied, 1824 (71.4%, followed by the colubrids Xenodon neuwiedii Günther, 1820 (33%, Chironius laevicollis (Wied, 1824 and Spilotes pullatus (Linnaeus, 1758 (both with 22%. The latter three species also showed the highest rates of infestation by A. rotundatum. The results of the present study suggest that a combination of skin shedding, habitat of the host, type of scale and pattern of scale distribution on the body of the host can influence the degree to which a given species is parasitized by ticks
JOHN D. LYNCH
Full Text Available Monocultures of the African oil palm (Elaeis guineensis Jacq. were studied between 2006 and 2013 so as to determine which species of snakes frequented them and to estimate the abundances of each species encountered. Thirty five species of snakes (three boas, one coral, 27 colubrids, one tropidophid, one typhlopid, and two vipers were captured within palmeras. Palm plantations are revealed to (1 augment the densities of ten species of snakes well beyond the densities found by collectors in natural and/or relatively transformed habitats and (2 to not offer benefits to at least 75% of the snake community found in the vicinities of palm plantations. The majority of snake species (60% found in palmeras are nocturnal species. The most common species (defined by having 15 or more captures were Atractus univittatus, Bothrops asper, B. atrox, Epicrates maurus, Leptodeira annulata, Liophis melanotus, Ninia atrata, Oxyrhopus petolarius, Pseudoboa neuwiedii, and Tantilla melanocephala. Palm plantations permit substantial local population sizes for a fraction (< 25% of the local snake community. Internal practices of such plantations could be modified so as to protect a larger share of the fauna by means of two practices: (1 construction and maintenance of paleras as well as (2 creating a mosaic of palm plantations enclosing "islands" of secondary forests.
McNamara, Maria E; Orr, Patrick J; Kearns, Stuart L; Alcalá, Luis; Anadón, Pere; Peñalver, Enrique
Evidence of original coloration in fossils provides insights into the visual communication strategies used by ancient animals and the functional evolution of coloration over time [1-7]. Hitherto, all reconstructions of the colors of reptile integument and the plumage of fossil birds and feathered dinosaurs have been of melanin-based coloration [1-6]. Extant animals also use other mechanisms for producing color , but these have not been identified in fossils. Here we report the first examples of carotenoid-based coloration in the fossil record, and of structural coloration in fossil integument. The fossil skin, from a 10 million-year-old colubrid snake from the Late Miocene Libros Lagerstätte (Teruel, Spain) [9, 10], preserves dermal pigment cells (chromatophores)-xanthophores, iridophores, and melanophores-in calcium phosphate. Comparison with chromatophore abundance and position in extant reptiles [11-15] indicates that the fossil snake was pale-colored in ventral regions; dorsal and lateral regions were green with brown-black and yellow-green transverse blotches. Such coloration most likely functioned in substrate matching and intraspecific signaling. Skin replicated in authigenic minerals is not uncommon in exceptionally preserved fossils [16, 17], and dermal pigment cells generate coloration in numerous reptile, amphibian, and fish taxa today . Our discovery thus represents a new means by which to reconstruct the original coloration of exceptionally preserved fossil vertebrates. Copyright © 2016 Elsevier Ltd. All rights reserved.
Janne K Valkonen
Full Text Available Most research into the adaptive significance of warning signals has focused on the colouration and patterns of prey animals. However, behaviour, odour and body shape can also have signal functions and thereby reduce predators' willingness to attack defended prey. European vipers all have a distinctive triangular head shape; and they are all venomous. Several non-venomous snakes, including the subfamily Natricinae, commonly flatten their heads (also known as head triangulation when disturbed. The adaptive significance of this potential behavioural mimicry has never been investigated.We experimentally tested if the triangular head shape typical of vipers offers protection against predation. We compared the predation pressure of free-ranging predators on artificial snakes with triangular-shaped heads against the pressure on replicas with narrow heads. Snakes of both head types had either zigzag patterned bodies, typical of European vipers, or plain (patternless bodies. Plain snakes with narrower Colubrid-like heads suffered significantly higher predation by raptors than snakes with triangular-shaped heads. Head shape did not, however, have an additive effect on survival in zigzag-patterned snakes, suggesting that species which differ from vipers in colouration and pattern would benefit most from behavioural mimicry. Our results demonstrate that the triangular head shape typical of vipers can act as a warning signal to predators. We suggest that head-shape mimicry may be a more common phenomenon among more diverse taxa than is currently recognised.
Full Text Available Rhabdophis tigrinus is a common colubrid snake that can be found in an extensive geographical region in East Asia. It consists of two subspecies: R.t. tigrinus (yamakagashi and R.t. formosanus (Taiwan tiger keelback. R. tigrinus possesses two different sets of poisonous glands: the Duvernoy's glands in the maxilla, and the nuchal glands in the dorsal skin of the neck. We report the first case in current English literature of toxin ophthalmia caused by the nuchal gland secretion of R.t. formosanus. The patient was a 40-year-old man whose right eye was sprayed by the nuchal gland fluid of R.t. formosanus. He presented with symptoms of foreign body sensation, progressive burning pain, and blurred vision. Ophthalmologic examination revealed diffuse superficial punctate keratitis, corneal stromal edema with Descemet folds, and conjunctival congestion. The patient responded well to topical treatment with a corticosteroid, antihistamine, and antibiotic, and had a favorable clinical course and outcome.
New localities and altitudinal records for the snakes Oxyrhopus petolarius, Spilotes pullatus, and Urotheca fulviceps in Talamanca, Costa Rica Nuevas localidades y registros de elevación de las serpientes Oxyrhopus petolarius, Spilotes pullatus y Urotheca fulviceps en Talamanca, Costa Rica
José F. González-Maya
Full Text Available Distribution records are the basis for conservation planning and species conservation assessments. New locality and elevation records are reported for 2 dipsadid snakes (Oxyrhopus petolarius and Urotheca fulviceps and 1 colubrid (Spilotes pullatus from the Talamanca mountain range of Costa Rica as established by direct sightings. These new records represent important additions to the knowledge of the species and more generally for the Talamanca ecoregion.Los registros de distribución de especies son la base para la planificación y evaluación del estado de conservación de éstas y los ecosistemas en que habitan. Se presentan 3 nuevas localidades y registros de elevación de 2 especies de dipsádidos (Oxyrhopus petolarius y Urotheca fulviceps y 1 especie de colúbrido (Spilotes pullatus en la cordillera de Talamanca, con base en observaciones directas. Estos registros representan importantes adiciones tanto para la ecoregión de Talamanca, como para el aumento significativo en el conocimiento de estas especies.
Full Text Available We observed the mating behavior of the neck-banded snake Scaphiodontophis annulatus (a common species of colubrid in the South Pacific of Costa Rica in the pre-montane wet forest of Las Cruces Biological Station (San Vito de Java, Costa Rica. Three S. annulatus were observed during courtship between 10-12 AM in a patch of primary forest. The two males were observed to interact with the female, but not signs of male-male agonistic interactions were observed. Their behavior includes grabbing and holding the female, copula, and biting during the copula. Rev. Biol. Trop. 54(2: 647-650. Epub 2006 Jun 01.El comportamiento de apareamiento es descrito para la serpiente Scaphiodontophis annulatus, una especie de colúbrido común en el Pacífico sur de Costa Rica. El comportamiento incluye capturar y sujetar a la hembra, mordiscos durante la cópula y coito. Dos machos fueron observados al interactuar con una sola hembra, pero no se detectó señales de interacciones antagónicas macho-macho.
Full Text Available Here, we update the current list of amphibian and reptile fauna present in the Balearic Islands, probably the most outstanding case in the Mediterranean and of the most in the world where massive species introduction is in conflict with the survivorship of highly restricted endemic taxa. Resulting of a long term evolution in insularity, endemic herpetofauna was already decimated during the Pleistocene but, after the human colonisation of the archipelago, the introduction of alien species, passive or deliberate, has been provoking new extinctions and range retractions in the native herpetofauna. Such process is not interrupted but has even intensified during the last years. The current species list is composed by five amphibians (one native and 21 reptiles (2 native. A critical review of the evidence on extinctions and introductions is provided together with the conservation implications. Compared to the last review (Mayol, 1985 six new reptile species are now naturalised or are in process of naturalization, colubrid snakes constituting the most conflicting element due to their predator role.
Gonçalves, Duarte Vasconcelos; Martínez-Freiría, Fernando; Crochet, Pierre-André; Geniez, Philippe; Carranza, Salvador; Brito, José Carlos
Highlands, hydrographic systems and coastal areas have been hypothesised to form corridors across the hyperarid Sahara desert in North Africa, allowing dispersal and gene flow for non-xeric species. Here we aim to provide a genetic test for the trans-Saharan corridor model, and predict the location and stability of ecological-corridors, by combining phylogeography and palaeoclimatic modelling. The model was the Psammophis schokari (Schokari sand racer) group, fast-moving and widely distributed generalist colubrids occurring mostly in arid and semiarid scrublands. We combined dated phylogenies of mitochondrial and nuclear markers with palaeoclimatic modelling. For the phylogeographic analysis, we used 75 samples of P. schokari and P. aegyptius, and Bayesian and Maximum-Likelihood methods. For the ecological models, we used Maxent over the distribution of P. schokari and West African lineages. Models were projected to past conditions (mid Holocene, Last Glacial Maximum and Last Inter-Glacial) to infer climatic stable areas. Climatic stability was predicted to be mostly restricted to coastal areas and not spatially continuous. A putative temporary trans-Saharan corridor was identified in Eastern Sahara, with a more stable one along the Atlantic coast. Six parapatric lineages were identified within P. schokari, four occurring in North Africa. These likely diverged during the Pliocene. The Tamanraset River might have been a vicariant agent. African lineages may have experienced further subsequent diversification during the late Pleistocene. The main P. schokari refugia were probably located along the northern margins of the Sahara, allowing its North-to-South colonization. Trans-Saharan corridors seem to have played a role in P. schokari biogeography, allowing colonization of central Saharan mountains and Sahel. Some might have worked as refugia, and even the most stable corridors may have sections working as filters, depending on each climatic phase. We expect the use
Powers, Kathryn G; Blackburn, Daniel G
Early amniotic vertebrates evolved large-yolked eggs that permitted production of well-developed, terrestrial hatchlings. This reproductive pattern required new mechanisms for cellularizing the yolk and mobilizing it for embryonic use. In birds, cells that line the yolk sac cavity phagocytose and digest the yolk material, a pattern that is commonly assumed to be universal among oviparous amniotes. However, recent evidence challenges the assumption that all squamate reptiles conform to the avian developmental pattern. In this paper, scanning electron microscopy and histology were used to study mechanisms of yolk processing in two colubrid snakes, the kingsnake Lampropeltis getula and the milksnake L. triangulum. Endodermal cells from the yolk sac splanchnopleure proliferate massively as they invade the yolk sac cavity, forming elaborate chains of interlinked cells. These cells grow in size as they phagocytose yolk material. Subsequently, vitelline capillaries invade the masses of yolk-laden cells and become coated with the endodermal cells, forming an elaborate meshwork of cell-coated strands. The close association of cells, yolk, and blood vessels allows yolk material to be cellularized, digested, and transported for embryonic use. The overall pattern is like that of the corn snake Pantherophis guttatus, but contrasts markedly with that of birds. Given recent evidence that this developmental pattern may also occur in certain lizards, we postulate that it is ancestral for squamates. Studies of lizards, crocodilians, and turtles are needed to clarify the evolutionary history of this pattern and its implications for the evolution of the amniotic (terrestrial) vertebrate egg. © 2017 Wiley Periodicals, Inc.
Sunagar, Kartik; Jackson, Timothy N. W.; Undheim, Eivind A. B.; Ali, Syed. A.; Antunes, Agostinho; Fry, Bryan G.
Three-finger toxins (3FTx) represent one of the most abundantly secreted and potently toxic components of colubrid (Colubridae), elapid (Elapidae) and psammophid (Psammophiinae subfamily of the Lamprophidae) snake venom arsenal. Despite their conserved structural similarity, they perform a diversity of biological functions. Although they are theorised to undergo adaptive evolution, the underlying diversification mechanisms remain elusive. Here, we report the molecular evolution of different 3FTx functional forms and show that positively selected point mutations have driven the rapid evolution and diversification of 3FTx. These diversification events not only correlate with the evolution of advanced venom delivery systems (VDS) in Caenophidia, but in particular the explosive diversification of the clade subsequent to the evolution of a high pressure, hollow-fanged VDS in elapids, highlighting the significant role of these toxins in the evolution of advanced snakes. We show that Type I, II and III α-neurotoxins have evolved with extreme rapidity under the influence of positive selection. We also show that novel Oxyuranus/Pseudonaja Type II forms lacking the apotypic loop-2 stabilising cysteine doublet characteristic of Type II forms are not phylogenetically basal in relation to other Type IIs as previously thought, but are the result of secondary loss of these apotypic cysteines on at least three separate occasions. Not all 3FTxs have evolved rapidly: κ-neurotoxins, which form non-covalently associated heterodimers, have experienced a relatively weaker influence of diversifying selection; while cytotoxic 3FTx, with their functional sites, dispersed over 40% of the molecular surface, have been extremely constrained by negative selection. We show that the a previous theory of 3FTx molecular evolution (termed ASSET) is evolutionarily implausible and cannot account for the considerable variation observed in very short segments of 3FTx. Instead, we propose a theory of
McCartney, Jacob A.; Stevens, Nancy J.; O’Connor, Patrick M.
The extant snake fauna has its roots in faunal upheaval occurring across the Paleogene - Neogene transition. On northern continents, this turnover is well established by the late early Miocene. However, this transition is poorly documented on southern landmasses, particularly on continental Africa, where no late Paleogene terrestrial snake assemblages are documented south of the equator. Here we describe a newly discovered snake fauna from the Late Oligocene Nsungwe Formation in the Rukwa Rift Basin of Tanzania. The fauna is small but diverse with eight identifiable morphotypes, comprised of three booids and five colubroids. This fauna includes Rukwanyoka holmani gen. et sp. nov., the oldest boid known from mainland Africa. It also provides the oldest fossil evidence for the African colubroid clade Elapidae. Colubroids dominate the fauna, comprising more than 75% of the recovered material. This is likely tied to local aridification and/or seasonality and mirrors the pattern of overturn in later snake faunas inhabiting the emerging grassland environments of Europe and North America. The early emergence of colubroid dominance in the Rukwa Rift Basin relative to northern continents suggests that the pattern of overturn that resulted in extant faunas happened in a more complex fashion on continental Africa than was previously realized, with African colubroids becoming at least locally important in the late Paleogene, either ahead of or as a consequence of the invasion of colubrids. The early occurrence of elapid snakes in the latest Oligocene of Africa suggests the clade rapidly spread from Asia to Africa, or arose in Africa, before invading Europe. PMID:24646522
Mccardle, Logan D; Fontenot, Clifford L
Road mortality is a significant threat to terrestrial vertebrates in many areas, and the novel thermal environment of black-topped roads may represent ecological traps for some species and demographic groups. We investigated the relationship between ambient temperature and on-road detection in a snake assemblage in southeastern Louisiana by comparing observations of live snakes on a black-topped road, across measurements of air temperature and road temperature on survey days. Analyses indicated on-road detection of snakes was significantly influenced by ambient temperature conditions for five snake species. Additionally, road temperatures, and the difference between air and road temperatures, were strong drivers of on-road snake detections. Permutation analysis methods revealed that significant temperature related group (species or sex) structure exists in occurrences of snakes on the roadway, and that road temperature was the strongest driver of species differences. We also compared how air and road temperatures affected occurrence on the road between sexes in the colubrid snakes Nerodia fasciata, Nerodia cyclopion, Thamnophis proximus, and Pantherophis obsoletus. Males and females of the viviparous species N. fasciata, N. cyclopion, and T. proximus diverged significantly in temperature preferences, with females found under warmer conditions, while males and females of the oviparous species P. obsoletus did not. Road temperature was also the strongest driver of differences between sexes. Our results indicate that black-topped roads are an ecological trap that is heavily influenced by sex, reproductive condition, and species specific thermoregulatory requirements, particularly for viviparous species. Copyright © 2015 Elsevier Ltd. All rights reserved.
Tsuihiji, Takanobu; Kearney, Maureen; Rieppel, Olivier
The neck and trunk regionalization of the presacral musculoskeletal system in snakes and other limb-reduced squamates was assessed based on observations on craniovertebral and body wall muscles. It was confirmed that myological features characterizing the neck in quadrupedal squamates (i.e., squamates with well-developed limbs) are retained in all examined snakes, contradicting the complete lack of the neck in snakes hypothesized in previous studies. However, the posterior-most origins of the craniovertebral muscles and the anterior-most bony attachments of the body wall muscles that are located at around the neck-trunk boundary in quadrupedal squamates were found to be dissociated anteroposteriorly in snakes. Together with results of a recent study that the anterior expression boundaries of Hox genes coinciding with the neck-trunk boundary in quadrupedal amniotes were dissociated anteroposteriorly in a colubrid snake, these observations support the hypothesis that structures usually associated with the neck-trunk boundary in quadrupedal squamates are displaced relative to one another in snakes. Whereas certain craniovertebral muscles are elongated in some snakes, results of optimization on an ophidian cladogram show that the most recent common ancestor of extant snakes would have had the longest craniovertebral muscle, M. rectus capitis anterior, that is elongated only by several segments compared with that of quadrupedal squamates. Therefore, even such a posteriorly displaced "cervical" characteristic plesiomorphically lies fairly anteriorly in the greatly elongated precloacal region of snakes, suggesting that the trunk, not the neck, would have contributed most to the elongation of the snake precloacal region. A similar dissociation of structures usually associated with the neck-trunk boundary in quadrupedal squamates is observed in limb-reduced squamates, suggesting that these forms and snakes may share a developmental mechanism producing modifications in the
Jacob A McCartney
Full Text Available The extant snake fauna has its roots in faunal upheaval occurring across the Paleogene-Neogene transition. On northern continents, this turnover is well established by the late early Miocene. However, this transition is poorly documented on southern landmasses, particularly on continental Africa, where no late Paleogene terrestrial snake assemblages are documented south of the equator. Here we describe a newly discovered snake fauna from the Late Oligocene Nsungwe Formation in the Rukwa Rift Basin of Tanzania. The fauna is small but diverse with eight identifiable morphotypes, comprised of three booids and five colubroids. This fauna includes Rukwanyoka holmani gen. et sp. nov., the oldest boid known from mainland Africa. It also provides the oldest fossil evidence for the African colubroid clade Elapidae. Colubroids dominate the fauna, comprising more than 75% of the recovered material. This is likely tied to local aridification and/or seasonality and mirrors the pattern of overturn in later snake faunas inhabiting the emerging grassland environments of Europe and North America. The early emergence of colubroid dominance in the Rukwa Rift Basin relative to northern continents suggests that the pattern of overturn that resulted in extant faunas happened in a more complex fashion on continental Africa than was previously realized, with African colubroids becoming at least locally important in the late Paleogene, either ahead of or as a consequence of the invasion of colubrids. The early occurrence of elapid snakes in the latest Oligocene of Africa suggests the clade rapidly spread from Asia to Africa, or arose in Africa, before invading Europe.
Wood, D.A.; Meik, J.M.; Holycross, A.T.; Fisher, R.N.; Vandergast, A.G.
Chionactis occipitalis (Western Shovel-nosed Snake) is a small colubrid snake inhabiting the arid regions of the Mojave, Sonoran, and Colorado deserts. Morphological assessments of taxonomy currently recognize four subspecies. However, these taxonomic proposals were largely based on weak morphological differentiation and inadequate geographic sampling. Our goal was to explore evolutionary relationships and boundaries among subspecies of C. occipitalis, with particular focus on individuals within the known range of C. o. klauberi (Tucson Shovel-nosed snake). Population sizes and range for C. o. klauberi have declined over the last 25 years due to habitat alteration and loss prompting a petition to list this subspecies as endangered. We examined the phylogeography, population structure, and subspecific taxonomy of C. occipitalis across its geographic range with genetic analysis of 1100 bases of mitochondrial DNA sequence and reanalysis of 14 morphological characters from 1543 museum specimens. We estimated the species gene phylogeny from 81 snakes using Bayesian inference and explored possible factors influencing genetic variation using landscape genetic analyses. Phylogenetic and population genetic analyses reveal genetic isolation and independent evolutionary trajectories for two primary clades. Our data indicate that diversification between these clades has developed as a result of both historical vicariance and environmental isolating mechanisms. Thus these two clades likely comprise 'evolutionary significant units' (ESUs). Neither molecular nor morphological data are concordant with the traditional C. occipitalis subspecies taxonomy. Mitochondrial sequences suggest specimens recognized as C. o. klauberi are embedded in a larger geographic clade whose range has expanded from western Arizona populations, and these data are concordant with clinal longitudinal variation in morphology. ?? 2007 Springer Science+Business Media B.V.
Luiselli, Luca; Akani, Godfrey C.
Most of the studies concerning the thermal and reproductive relationships of snakes have been conducted in temperate regions, whereas very few data are available for African tropical species. In the present study, aspects of the comparative thermal and reproductive ecology of four sympatric freshwater snakes from tropical Africa (the colubrids Natriciteres fuliginoides, N. variegata, Afronatrix anoscopus, and Grayia smythii) are studied with emphasis on exploring whether their thermal ecology relations with reproduction biology may indicate a substantial influence of thermoregulation on their life-history traits (as shown in several studies from temperate-zone reptiles), or whether thermoregulatory biology is less important in tropical reptiles (as suggested in some recent experimental studies). The present study showed that, with minor species-specific differences, thermoregulation certainly has some relevance for the activity and life-history attributes of the studied species, as (i) the females tended to show body temperatures inversely related to their size (snout-vent length), and (ii) gravid specimens tended to maintain higher body temperatures than non-gravid specimens. However, other sets of our data (e.g., the high and constant Tb exhibited during night-time) strongly indicate that these four species of tropical water snakes can maintain high and stable Tb with little overt thermoregulatory behaviour. As is the rule in most of the other snake species studied to date, the maternal size of the females strongly influenced the number of eggs produced, and testifies that reproductive biology models linking reproductive performance to thermal ecology, highlighted in other snakes from temperate and cool regions, may well apply at least to some extent also to these Afrotropical species.
Plylar, Helen Bond
Vision in vertebrates generally relies on the refractive power of the cornea and crystalline lens to facilitate vision. Light from the environment enters the eye and is refracted by the cornea and lens onto the retina for production of an image. When an animal with a system designed for air submerges underwater, the refractive power of the cornea is lost. Semi-aquatic animals (e.g., water snakes, turtles, aquatic mammals) must overcome this loss of corneal refractive power through visual accommodation. Accommodation relies on change of the position or shape of the lens to change the focal length of the optical system. Intraocular muscles and fibers facilitate lenticular displacement and deformation. Snakes, in general, are largely unstudied in terms of visual acuity and intraocular morphology. I used light microscopy and scanning electron microscopy to examine differences in eye anatomy between five sympatric colubrid snake species (Nerodia cyclopion, N. fasciata, N. rhombifer, Pantherophis obsoletus, and Thamnophis proximus) from Southeast Louisiana. I discovered previously undescribed structures associated with the lens in semi-aquatic species. Photorefractive methods were used to assess refractive error. While all species overcame the expected hyperopia imposed by submergence, there was interspecific variation in refractive error. To assess scaling of eye size with body size, I measure of eye size, head size, and body size in Nerodia cyclopion and N. fasciata from the SLU Vertebrate Museum. In both species, body size increases at a significantly faster rate than head size and eye size (negative allometry). Small snakes have large eyes relative to body size, and large snakes have relatively small eyes. There were interspecific differences in scaling of eye size with body size, where N. fasciata had larger eye diameter, but N. cyclopion had longer eyes (axial length).
Background The extant squamates (>9400 known species of lizards and snakes) are one of the most diverse and conspicuous radiations of terrestrial vertebrates, but no studies have attempted to reconstruct a phylogeny for the group with large-scale taxon sampling. Such an estimate is invaluable for comparative evolutionary studies, and to address their classification. Here, we present the first large-scale phylogenetic estimate for Squamata. Results The estimated phylogeny contains 4161 species, representing all currently recognized families and subfamilies. The analysis is based on up to 12896 base pairs of sequence data per species (average = 2497 bp) from 12 genes, including seven nuclear loci (BDNF, c-mos, NT3, PDC, R35, RAG-1, and RAG-2), and five mitochondrial genes (12S, 16S, cytochrome b, ND2, and ND4). The tree provides important confirmation for recent estimates of higher-level squamate phylogeny based on molecular data (but with more limited taxon sampling), estimates that are very different from previous morphology-based hypotheses. The tree also includes many relationships that differ from previous molecular estimates and many that differ from traditional taxonomy. Conclusions We present a new large-scale phylogeny of squamate reptiles that should be a valuable resource for future comparative studies. We also present a revised classification of squamates at the family and subfamily level to bring the taxonomy more in line with the new phylogenetic hypothesis. This classification includes new, resurrected, and modified subfamilies within gymnophthalmid and scincid lizards, and boid, colubrid, and lamprophiid snakes. PMID:23627680
Greene, Sara; McConnachie, Suzanne; Secor, Stephen; Perrin, Mike
African egg-eating snakes (Dasypeltis) feed only on freshly laid bird eggs which they perforate within their esophagus before swallowing the liquid contents and regurgitating the empty shell. Compared to a snake's typical intact meal, the liquid diet of Dasypeltis would expectedly generate a more moderate postprandial metabolic response and specific dynamic action (SDA). Free-ranging Dasypeltis feed over a range of ambient temperatures and thereby experience predicted temperature-dependent shifts in the duration and magnitude of their postprandial metabolic response. Such shifts would undoubtedly be shared among different species and age classes of Dasypeltis. To examine these expectations, we measured pre- and postprandial metabolic rates of adult Dasypeltis inornata and adult and neonate Dasypeltis scabra in response to liquid egg meals weighing 20% of snake body mass at 20, 25, 27, 30, and 32 °C. With an increase in body temperature, postprandial metabolic profiles of neonate and adult snakes became narrower and shorter in duration. Specific dynamic action varied among temperature treatments, increasing from 20 to 32 °C. Standard metabolic rate, postprandial peak metabolic rate, and SDA scaled with mass exponents that typically did not differ from 1.0. As expected, Dasypeltis digesting a liquid egg diet experienced a more modest postprandial response and SDA, expending on average only 10.6% of the meal's energy on the breakdown, absorption, and assimilation of the egg meal, whereas other colubrids consuming intact rodent or fish meals expend on average 16.3% of the meal's energy on digestion and assimilation. Actively foraging and feeding throughout the avian egg laying season enable Dasypeltis to survive when eggs are not available. The adaptive suite of traits that enable Dasypeltis to consume eggs of large relative size and ingest only the liquid contents may also be joined by physiological adaptations specific to their liquid diet and extended bouts of
Telford, Sam R; Moler, Paul E; Butler, Jerry F
Records from a colubrid host are reported for Hepatozoon horridus, described originally from a viperid snake. Hepatozoon horridus in Pantherophis guttatus (Colubridae) has gamonts 14-18.0 by 4.0-5.5 microm, with length by width (LW) 60-99 microm2, and L/W ratio 2.5-3.9. Spherical to elongate, usually ovoid oocysts with L/W ratio 1.0-3.7 contain 16-160 spherical to usually ovoid sporocysts 15-31 by 14-26 microm, with L/W ratio 1.0-1.4, that contain 5-24 sporozoites. Two additional Hepatozoon species are described from ratsnakes in north Florida. Hepatozoon quadrivittata n. sp. from Pantherophis obsoletus quadrivittatus has gamonts 12-17 by 4-6 microm, LW 56-102 microm2, and L/W ratio 2.6-3.8. Nearly spherical oocysts with L/W 1.0-1.1 contain 5-227 spherical to slightly ovoid sporocysts 20-48 by 19-45 microm, with L/W ratio 1.0-1.4, that contain 13-48 sporozoites. Hepatozoon spiloides n. sp. from Pantherophis obsoletus spiloides forms gamonts 12-15 by 4-5 microm with LW 48-75 microm2 and L/W ratio 2.6-3.5. Occasionally rounded but usually elongate oocysts, with L/W ratio 1.0-2.7, contain 5-21 spherical to elongate sporocysts 28-43 by 18-35 microm, L/W ratio 2.5-3.9. In the distinctive Hepatozoon sp. present in Pantherophis obsoletus spiloides, gamonts are 13-17 by 5-10 microm, with LW 75-140 microm2 and L/W ratio 1.4-3.0. Infected erythrocytes are always distorted and enlarged on average 2.5 times the size of uninfected cells, with nuclei enlarged by one-third and broadly elongated. Gamonts often stained deep blue, and cytoplasm of erythrocytes infected with mature gamonts was always dehemoglobinized. Sporogony could not be obtained in three feedings by hundreds of Aedes aegypti, which usually died within the first 24-48 hr.
Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S
Fangs are specialised long teeth that contain either a superficial groove (Gila monster, Beaded lizard, some colubrid snakes), along which the venom runs, or an enclosed canal (viperid, elapid and atractaspid), down which the venom flows inside the tooth. The fangs of viperid snakes are the most effective venom-delivery structures among vertebrates and have been the focus of scientific interests for more than 200 years. Despite this interest the questions of how the canal at the centre of the fang forms remains unresolved. Two different hypotheses have been suggested. The mainstream hypothesis claims that the venom-conducting canal develops by the invagination of the epithelial wall of the developing tooth germ. The sides of this invagination make contact and finally fuse to form the enclosed canal. The second hypothesis, known as the "brick chimney", claims the venom-conducting canal develops directly by successive dentine deposition as the tooth develops. The fang is thus built up from the tip to the base, without any folding of the tooth surface. In an attempt to cast further light on this subject the early development of the fangs was followed in a pit viper, Trimeresurus albolabris, using the expression of Sonic hedgehog (Shh). We demonstrate that the canal is indeed formed by an early folding event, resulting from an invagination of epithelial cells into the dental mesenchyme. The epithelial cells proliferate to enlarge the canal and then the cells die by apoptosis, forming an empty tube through which the poison runs. The entrance and discharge orifices at either end of the canal develop by a similar invagination but the initial width of the invagination is very different from that in the middle of the tooth, and is associated with higher proliferation. The two sides of the invaginating epithelium never come into contact, leaving the orifice open. The mechanism by which the orifices form can be likened to that observed in reptiles with an open groove along
Chafiq, Fouad; El Hattimy, Faiçal; Rhalem, Naima; Chippaux, Jean-Philippe; Soulaymani, Abdelmajid; Mokhtari, Abdelrhani; Soulaymani-Bencheikh, Rachida
Snakebites cause considerable death and injury throughout the globe, particularly in tropical regions, and pose an important yet neglected threat to public health. In 2008, the Centre Anti Poison et de Parmacovigilance du Maroc (CAPM) started to set up a specific strategy for the control of snakebites that was formalized in 2012. The aim of the present study is to describe and update the epidemiological characteristics of snakebites notified to CAPM between 2009 and 2013. This retrospective five-year study included all cases of snakebites notified to CAPM by mail or phone. During the study period, 873 snakebite cases were reported to CAPM, an average incidence of 2.65 cases per 100,000 inhabitants with 218 cases each year. The highest incidence was found in Tangier-Tetouan region with 357 cases (40.9 %) followed by Souss Massa Draa region with 128 cases (14.6 %). The average age of patients was 26.8 ± 17.2 years. The male to female sex ratio was 1.67:1 and 77 % of cases occurred in rural areas. The bites occurred mainly in spring (44 %) followed by summer (42 %). Snake species was identified in 54 cases (6.2 %): colubrids represented 31 % (n = 18) and vipers 67 % (n = 36), mainly Daboia mauritanica, Bitis arietans and Cerastes cerastes. In 311 cases (35.6 %), the patients showed viper syndrome. Thrombocytopenia was observed in 23.5 % of viper syndrome cases, whereas, compartment syndrome was observed in 7.6 % patients. FAV-Afrique® was administered in 41 patients (5 %). In patients treated with antivenom, 38 patients recovered and three died. Twenty-seven deaths were reported (3.9 %). Despite specific efforts to better understand the epidemiology of snakebites in Morocco (incidence, severity, snake species involved), it remains underestimated. Therefore, further work is still necessary to ensure accessibility of appropriate antivenom against venomous species and to improve the management of envenomation in Morocco.
Full Text Available Venomous snakebite is considered the single most important cause of human injury from venomous animals worldwide. Coagulopathy is one of the commonest important systemic clinical syndromes and can be complicated by serious and life-threatening haemorrhage. Venom-induced consumption coagulopathy (VICC is the commonest coagulopathy resulting from snakebite and occurs in envenoming by Viperid snakes, certain elapids, including Australian elapids, and a few Colubrid (rear fang snakes. Procoagulant toxins activate the clotting pathway, causing a broad range of factor deficiencies depending on the particular procoagulant toxin in the snake venom. Diagnosis and monitoring of coagulopathy is problematic, particularly in resource-poor countries where further research is required to develop more reliable, cheap clotting tests. MEDLINE and EMBASE up to September 2013 were searched to identify clinical studies of snake envenoming with VICC. The UniPort database was searched for coagulant snake toxins. Despite preclinical studies demonstrating antivenom binding toxins (efficacy, there was less evidence to support clinical effectiveness of antivenom for VICC. There were no placebo-controlled trials of antivenom for VICC. There were 25 randomised comparative trials of antivenom for VICC, which compared two different antivenoms (ten studies, three different antivenoms (four, two or three different doses or repeat doses of antivenom (five, heparin treatment and antivenom (five, and intravenous immunoglobulin treatment and antivenom (one. There were 13 studies that compared two groups in which there was no randomisation, including studies with historical controls. There have been numerous observational studies of antivenom in VICC but with no comparison group. Most of the controlled trials were small, did not use the same method for assessing coagulopathy, varied the dose of antivenom, and did not provide complete details of the study design (primary outcomes
Gross, M.; Böhme, M.; Prieto, J.
Integrated stratigraphic approaches provide precise correlations of global standard stages with regional Paratethys stages. Nevertheless, higher resolution stratigraphic matching of terrestrial deposits remains challenging due to the lack of a practical continental biostratigraphy. The mostly used tool for biostratigraphic correlation of non-marine deposits in the Old World is still the concept of Neogene Mammal-zones (MN-zones). However, at higher biostratigraphic resolution (reptiles (scincids, lacertids, gekkonids, anguids, varanids, colubrids, testudinids, emydids), birds (coliiformes), rodents and lagomorphs (cricetids, glirids, eomyids, sciurids, castorids), insectivores and chiropterans (erinaceids, soricids, talpids), and large mammals (suids, tragulids, moschids, cervids, ?palaeomerycids, equids, chalicotheriids, rhinos, proboscidians, carnivors). Litho- and biostratigraphy (terrestrial gastropods) as well as magnetostratigraphic data and the sequence stratigraphic and geodynamic frame indicate an age of 12-12.2 Ma (early Late Sarmatian s.str., chron 5An.1n) for the locality. Therefore, Gratkorn is one of richest and most complete fauna of the late Middle Miocene of Central Europe and will be confidentially one of the key faunas for a high-resolution continental biostratigraphy and the comprehension of the faunal succession and interchanges near the Middle/Late Miocene transition. Acknowledgements This is a preliminary overview of the Gratkorn vertebrate fauna. Several taxa are still under investigation. We are especially grateful to Gudrun Daxner-Höck, Ursula Göhlich (both Natural History Museum Vienna) and Getrud Rössner (University of Munich) for their comments to the rodents, ruminants, proboscidians and bird remains. References Böhme, M., Ilg, A., Winklhofer, M. 2008. Late Miocene "washhouse" climate in Europe.- Earth and Planetary Science Letters, 275: 393-401. Gross, M., 2008. A limnic ostracod fauna from the surroundings of the Central
Dieta e uso de habitat da jararaca-do-brejo, Mastigodryas bifossatus Raddi (Serpentes, Colubridade em domínio subtropical do Brasil Diet and habitat use of swamp racer snake, Mastigodryas bifossatus Raddi (Serpentes, Colubridae in subtropical domains of Brazil
Pedro T. Leite
Full Text Available A serpente Mastigodryas bifossatus Raddi, 1820 é um grande colubrídeo neotropical que habita áreas abertas na América do Sul. Sua dieta é composta principalmente por anfíbios, mas inclui outros itens como mamíferos e lagartos. A dissecção de 224 espécimes desta serpente, provenientes dos estados do Rio Grande do Sul, Santa Catarina e Paraná, preservados em coleções herpetológicas do Brasil e um estudo de campo entre 1996 e 1998, fornecem informações sobre os hábitos alimentares e uso de habitat dessa serpente em domínio subtropical no Brasil. Essa serpente alimenta-se de anfíbios (80%, em sua maioria da família Leptodactylidae, mamíferos (10% e lagartos (2%. Foi verificada mudança ontogenética na dieta de M. bifossatus, o tamanho das presas ingeridas aumenta com o aumento de tamanho da serpente. Essa espécie ocorre principalmente em áreas abertas, algumas vezes perto de áreas antrópicas em domínio subtropical no Brasil.Mastigodryas bifossatus Raddi, 1820 is a large neotropical colubrid snake that inhabits open areas in South America. The diet is mainly composed by frogs, but it includes other items like mammals and lizards. The dissection of 224 specimens of this snake, proceeding from the states of Rio Grande do Sul, Santa Catarina and Paraná, stored in herpetological collections in Brazil and a field study between 1996 and 1998, provided information on dietary habits and habitat use of this snake in subtropical domains in Brazil. This snake eats mainly amphibians of the family Leptodactylidae (80%, mammals (10% and lizards (2%. There is ontogenetic diet shift in M. bifossatus, as the snake grows, the range of preys grows as well. M. bifossatus occur in open areas.
Sunagar, Kartik; Johnson, Warren E; O'Brien, Stephen J; Vasconcelos, Vítor; Antunes, Agostinho
mechanism employed by the organism. CRISPs in Elapidae, which mostly employ neurotoxins, have experienced less positive selection pressure (ω = 2.86) compared with the "nonvenomous" colubrids (ω = 4.10) that rely on grip and constriction to capture the prey, and the Viperidae, a lineage that mostly employs haemotoxins (ω = 4.19). Relatively lower omega estimates in Anguimorph lizards (ω = 2.33) than snakes (ω = 3.84) suggests that lizards probably depend more on pace and powerful jaws for predation than venom.
Marcos André de Carvalho
Full Text Available São apresentadas informações sobre as serpentes da área urbana do Município de Cuiabá, Mato Grosso, potencialmente causadoras de acidentes ofídicos. As informações estão baseadas em exemplares doados por populares ao Núcleo de Ofiologia Regional de Mato Grosso (Normat entre 1986 e 1993 e em registros efetuados pelo Centro de Informações Anti-Veneno (Ciave entre 1988 e 1993, que não fazem referência ao animal causador. Foram catalogadas 37 espécies de serpentes, em 25 gêneros e 3 famílias, com hábitos predominantemente diurnos, terrestres e com dietas baseadas em anfíbios e/ou lagartos. Dentre os 307 acidentes ofídicos registrados, 56% foram causados por serpentes sem interesse médico e 44% constituíram acidentes de importância médica. Cerca de 99% dos acidentes de importância médica foram atribuídos ao gênero Bothrops (Bothrops moojeni e Bothrops neuwiedi seriam as principais causadoras. Dentre as espécies sem interesse médico, Philodryas olfersii e Waglerophis merremii provavelmente foram as principais responsáveis pela maior parte dos acidentes.This study presents data on snakes recorded in the urban area of Cuiabá, Mato Grosso, Brazil. Sources of information included specimens captured by local residents (1986-1993 and turned over to the Mato Grosso Regional Ophiological Center (Normat, and data from the Anti-Venom Information Center (Ciave, regarding urban snakebites (1988-1993. Thirty-seven species of snakes from 25 genera and three families were recorded. Diurnal and terrestrial habits predominated, as well as a diet based on amphibians and/or lizards. From a total of 307 snakebites recorded, some 56% were of no clinical importance, caused by non-venomous snakes, whereas 44% were clinically relevant. Approximately 99% of the latter were attributed to vipers of the genus Bothrops, and especially the Bothrops moojeni and Bothrops neuwiedi species The colubrids Philodryas olfersii and Waglerophis merremii were
Full Text Available Remains of Neogene and Quaternary "natricine" colubrids, elapids and viperids, including snakes previously described and those undescribed yet, coming from Poland, Ukraine, Moldavia, Czechoslovakia, Austria, Hungary, Romania, Bulgaria, and Greece are discussed. The following taxa, including 11 extinct species, were recognized: "Natricinae": Neonatrix nova, Neonatrix sp., Palaeonatrix silesiaca, Palaeonatrix lehmani, Natrix longivertebrata, Natrix cf. N. longivertebrata, Natrix natrix, Natrix tesselata, Natrix cf. N. tesselata, Natrix sp., "Natricinae" indet.; Elapidae: Naja romani, Naja sp., cf. Naja sp.; Viperidae: Vipera platyspondyla, Vipera sarmatica, Vipera burgenlandica, Vipera gedulyi, Vipera kuchurganica, Vipera antiqua, Vipera cf. V. ammodytes, Vipera berus, Vipera sp ('Oriental vipers' group, Vipera sp. ('aspis' group, Vipera sp. ('berus' group, Vipera sp. . (status unknown. Taxonomic status of two other extinct species, Natrix parva and Laophis crotaloides, is uncertain. Modern species appeared fírst in Central and East Europe in the middle Pliocene (MN 15. Older snakes belonged to extinct species of either extinct or extant genera; taxonomic distinction of most extinct genera is, however, not fully demonstrated. Best recognized oldest snakes from the area (Elapidae, Viperidae, and sorne Colubridae are clearly referable to modern genera and intrageneric subdivisions occurring today are observed in oldest (Iower Miocene remains; closest living relatives of these fossils are presently distributed in the Oriental Realm.Se revisan y estudian los restos neógenos y cuaternarios de colúbridos Â«natricinosÂ», elápidos y vipéridos, incluyendo tanto serpientes previamente descritas como- otras inéditas. Los materiales analizados proceden de Polonia, Ukrania, Moldavia, Checoslovaquia, Austria, Hungría, Rumania, Bulgaria y Grecia. Se reconocen los siguientes taxones, incluyendo 11 especies extinguidas: Natricinae: Neonatrix nova