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New world coralsnakes of the genus Micrurus are a diverse radiation of highly venomous and brightly colored snakes that range from North Carolina to Argentina. Species in this group have played central roles in developing and testing hypotheses about the evolution of mimicry and aposematism. Despite their diversity and prominence as model systems, surprisingly little is known about species boundaries and phylogenetic relationships within Micrurus, which has substantially hindered meaningful analyses of their evolutionary history. Here we use mitochondrial genes together with thousands of nuclear genomic loci obtained via ddRADseq to study the phylogenetic relationships and population genomics of a subclade of the genus Micrurus: The M. diastema species complex. Our results indicate that prior species and species-group inferences based on morphology and color pattern have grossly misguided taxonomy, and that the M. diastema complex is not monophyletic. Based on our analyses of molecular data, we infer the phylogenetic relationships among species and populations, and provide a revised taxonomy for the group. Two non-sister species-complexes with similar color patterns are recognized, the M. distans and the M. diastema complexes, the first being basal to the monadal Micrurus and the second encompassing most North American monadal taxa. We examined all 13 species, and their respective subspecies, for a total of 24 recognized taxa in the M. diastema species complex. Our analyses suggest a reduction to 10 species, with no subspecific designations warranted, to be a more likely estimate of species diversity, namely, M. apiatus, M. browni, M. diastema, M. distans, M. ephippifer, M. fulvius, M. michoacanensis, M. oliveri, M. tener, and one undescribed species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A stable alpha taxonomy is essential to understanding evolutionary processes and achieving effective conservation aims. Taxonomy depends on the identification of independently evolving lineages, and the delimitation of these lineages based on multiple lines of evidence. Coalescent species delimitation within an integrative framework has increased the rigor of the delimitation process. Here we use genome-wide SNP data and coalescent species delimitation to explore lineage relationships within several North American whipsnake species, test the species status of several lineages, and test the effect of missing data on species delimitation. We find support for the elevation of several previously recognized subspecies to full species status, and formally elevate two species. This study demonstrates the power of molecular data and model-based delimitation methods to identify evolutionary relationships, and finds that missing data have little impact on the outcome of delimitation analyses., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Geological and climatological processes can drive the synchronous diversification of co-distributed species. The islands of Sumatra and Java have experienced complex geological and climatological histories, including extensive sea-level changes and the formation of valleys between northern, central, and southern components of the Barisan Mountain Range, which may have promoted diversification of their resident species. We investigate diversification on these islands using 13 species of the parachuting frog genus Rhacophorus. We use both mitochondrial and nuclear sequence data, along with genome-wide SNPs to estimate phylogenetic structure and divergence times, and to test for synchronous diversification. We find support for synchronous divergence among sister-species pairs from Sumatra and Java ∼9 Ma, as well as of populations of four co-distributed taxa on Sumatra ∼5.6 Ma. We found that sister species diverged in allopatry on Sumatra and conclude that divergence on Sumatra and Java was affected by sea-level fluctuations that promoted isolation in allopatry., (Copyright © 2018 Elsevier Inc. All rights reserved.)

We redescribe Cyrtodactylus lateralis (Werner) on the basis of new specimens. Cyrtodactylus lateralis is a prehensile-tailed species, known from scattered lowland to mid-elevation localities in northern Sumatra. The prehensile-tailed Cyrtodactylus are more speciose and have a wider distribution than previously thought. This group includes a mainland SE Asian clade consisting of C. elok, C. interdigitalis, and C. brevipalmatus and an insular clade containing C. durio, C. lateralis, C. nuaulu, C. serratus, C. spinosus, and C. stresemanni. However, a distinctive color pattern in the Wallacean and Papuan species and uncertainty surrounding the type locality of C. stresemanni raise unresolved questions about the inclusiveness of the insular clade. DNA sequence data supports a close relationship between C. elok and C. interdigitalis, but also reveals that C. lateralis and C. durio are not closely related to these species.

Interspecific gene flow is pervasive throughout the tree of life. Although detecting gene flow between populations has been facilitated by new analytical approaches, determining the timing and geography of hybridization has remained difficult, particularly for historical gene flow. A geographically explicit phylogenetic approach is needed to determine the overlap of ancestral populations. In this study, we performed population genetic analyses, species delimitation, simulations and a recently developed approach of species tree diffusion to infer the phylogeographic history, timing and geographic extent of gene flow in lizards of the Sceloporus spinosus group. The two species in this group, S. spinosus and S. horridus, are distributed in eastern and western portions of Mexico, respectively, but populations of these species are sympatric in the southern Mexican highlands. We generated data consisting of three mitochondrial genes and eight nuclear loci for 148 and 68 individuals, respectively. We delimited six lineages in this group, but found strong evidence of mito-nuclear discordance in sympatric populations of S. spinosus and S. horridus owing to mitochondrial introgression. We used coalescent simulations to differentiate ancestral gene flow from secondary contact, but found mixed support for these two models. Bayesian phylogeography indicated more than 60% range overlap between ancestral S. spinosus and S. horridus populations since the time of their divergence. Isolation-migration analyses, however, revealed near-zero levels of gene flow between these ancestral populations. Interpreting results from both simulations and empirical data indicate that despite a long history of sympatry among these two species, gene flow in this group has only recently occurred., (© 2015 John Wiley & Sons Ltd.)

The longtailed rattlesnakes of western Mexico represent an enigmatic group of poorly known venomous snake species: Crotalus ericsmithi, C. lannomi, and C. stejnegeri. In the 120 years since their discovery, fewer than twenty individuals have been deposited in natural history collections worldwide. These three species share similar morphological traits, including a particularly long tail that has been interpreted as either an ancestral condition among rattlesnakes or as derived within the longtailed group. An understanding of the phylogenetic distinctiveness and relationships among the longtailed rattlesnakes, and their relationships to other rattlesnake groups, has previously been hampered by a dearth of comparative material and tissues for collection of DNA sequence data. Facilitated by the recent availability of tissue samples from multiple individuals of each species, we estimate the phylogenetic relationships among the longtailed rattlesnakes and their placement among other rattlesnake groups, using DNA sequence data from three mitochondrial and three nuclear gene fragments. We explore phylogenetic signal in our data using Bayesian and maximum likelihood methods, species tree analyses and hypothesis testing. Our results strongly support the monophyly of longtailed rattlesnakes and suggest the three species diverged from each other during the mid to late Pliocene or early Pleistocene (~1.5-5.6 mya). Contrary to prevailing hypotheses, we find no evidence for an early or basal divergence of the longtailed clade within the rattlesnake tree, and instead estimate that it diverged relatively recently (~6.8 mya) from its sister lineage, composed of the diamondback rattlesnakes (C. atrox group) and the prairie rattlesnakes (C. viridis group). With our added sampling of lineages and identification of previously used problematic sequences, we provide a revised hypothesis for relationships among Crotalus species, yet underscore the need for future studies and new data to deliver a well-supported robust estimate of rattlesnake relationships., (Copyright © 2013 Elsevier Inc. All rights reserved.)

We investigated genetic variation within the Great Plains narrow-mouthed toad, Gastrophryne olivacea, across its geographic range in the United States and Mexico. An analysis of mitochondrial DNA (mtDNA) from 105 frogs revealed remarkably low levels of genetic diversity in individuals inhabiting the central United States and northern Mexico. We found that this widespread matrilineal lineage is divergent (ca. 2% in mtDNA) from haplotypes that originate from the western United States and western coast of Mexico. Using a dataset that included all five species of Gastrophryne and both species of the closely related genus Hypopachus, we investigated the phylogenetic placement of G. olivacea. This analysis recovered strong support that G. olivacea, the tropically distributed G. elegans, and the temperately distributed G. carolinensis constitute a monophyletic assemblage. However, the placement of G. pictiventris and G. usta render Gastrophryne paraphyletic with respect to Hypopachus. To complement our mitochondrial analysis, we examined a small fragment of nuclear DNA and recovered consistent patterns. In light of our findings we recommend (1) the resurrection of the nomen G. mazatlanensisTaylor (1943) for the disjunct western clade of G. olivacea and (2) the tentative placement of G. pictiventris and G. usta in Hypopachus. To explore possible scenarios leading to low levels of genetic diversity in G. olivacea, we used mismatch distributions and Bayesian Skyline plots to examine historic population expansion and demography. Collectively these analyses suggest that G. olivacea rapidly expanded in effective population size and geographic range during the late Pleistocene or early Holocene. This hypothesis is consistent with fossil data from northern localities and contemporary observations that suggest ongoing northern expansion. Given our findings, we suspect that the rapid range expansion of G. olivacea may have been facilitated by ecological associations with open habitats and seasonal water bodies., (Copyright © 2012 Elsevier Inc. All rights reserved.)

We present the first phylogenetic study on the widespread Middle American microhylid frog genus Hypopachus. Partial sequences of mitochondrial (12S and 16S ribosomal RNA) and nuclear (rhodopsin) genes (1275 bp total) were analyzed from 43 samples of Hypopachus, three currently recognized species of Gastrophryne, and seven arthroleptid, brevicipitid and microhylid outgroup taxa. Maximum parsimony (PAUP), maximum likelihood (RAxML) and Bayesian inference (MrBayes) optimality criteria were used for phylogenetic analyses, and BEAST was used to estimate divergence dates of major clades. Population-level analyses were conducted with the programs NETWORK and Arlequin. Results confirm the placement of Hypopachus and Gastrophryne as sister taxa, but the latter genus was strongly supported as paraphyletic. The African phrynomerine genus Phrynomantis was recovered as the sister taxon to a monophyletic Chiasmocleis, rendering our well-supported clade of gastrophrynines paraphyletic. Hypopachus barberi was supported as a disjunctly distributed highland species, and we recovered a basal split in lowland populations of Hypopachus variolosus from the Pacific versant of Mexico and elsewhere in the Mesoamerican lowlands. Dating analyses from BEAST estimate speciation within the genus Hypopachus occurred in the late Miocene/early Pliocene for most clades. Previous studies have not found bioacoustic or morphological differences among these lowland clades, and our molecular data support the continued recognition of two species in the genus Hypopachus., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Lineage diversification in the Neotropics is an interesting topic in evolutionary biology but is also one of the least understood. The abiotic and biotic complexity of the region precludes generalizations that can be drawn regarding the historical evolutionary processes responsible for the diversity observed. The snake genus Leptodeira provides an excellent opportunity to investigate such processes because it spans the entire Neotropical region. In this study, we infer the phylogenetic position of Leptodeira within Dipsadinae, estimate evolutionary relationships among and within Leptodeira species, and estimate the diversification time and biogeography of the genus. Three mitochondrial gene regions were sequenced for individuals representing all the Leptodeira species and most subspecies currently recognized. Additionally, two nuclear protein-coding gene regions were sequenced for representatives of each species and several genera within the Dipsadinae. We infer that several Leptodeira species are either paraphyletic or polyphyletic as currently recognized, and that most recognized subspecies are not monophyletic lineages. Despite the taxonomic discordance with evolutionary relationships, clades appear to correspond very well to major biogeographic regions of Mexico, Central America and South America. Our results thus highlight the important role of the Miocene and Pliocene for lineage diversification in the Neotropics. Additionally, our time estimates suggest that recent intraspecific phylogeographic structure is likely the result of habitat and climatic fluctuations during the Pleistocene. Cumulatively, our inferences of lineage diversification within Leptodeira suggest a complex evolutionary scenario in the Mexican transition zone and a north to south expansion with a final colonization of the tropics in South America.

We report the first phylogenetic analysis of DNA sequence data for the Central American component of the genus Eleutherodactylus (Anura: Leptodactylidae: Eleutherodactylinae), one of the most ubiquitous, diverse, and abundant components of the Neotropical amphibian fauna. We obtained DNA sequence data from 55 specimens representing 45 species. Sampling was focused on Central America, but also included Bolivia, Brazil, Jamaica, and the USA. We sequenced 1460 contiguous base pairs (bp) of the mitochondrial genome containing ND2 and five neighboring tRNA genes, plus 1300 bp of the c-myc nuclear gene. The resulting phylogenetic inferences were broadly concordant between data sets and among analytical methods. The subgenus Craugastor is monophyletic and its initial radiation was potentially rapid and adaptive. Within Craugastor, the earliest splits separate three northern Central American species groups, milesi, augusti, and alfredi, from a clade comprising the rest of Craugastor. Within the latter clade, the rhodopis group as formerly recognized comprises three deeply divergent clades that do not form a monophyletic group; we therefore restrict the content of the rhodopis group to one of two northern clades, and use new names for the other northern (mexicanus group) and one southern clade (bransfordii group). The new rhodopis and bransfordii groups together form the sister taxon to a clade comprising the biporcatus, fitzingeri, mexicanus, and rugulosus groups. We used a Bayesian MCMC approach together with geological and biogeographic assumptions to estimate divergence times from the combined DNA sequence data. Our results corroborated three independent dispersal events for the origins of Central American Eleutherodactylus: (1) an ancestor of Craugastor entered northern Central America from South American in the early Paleocene, (2) an ancestor of the subgenus Syrrhophus entered northern Central America from the Caribbean at the end of the Eocene, and (3) a wave of independent dispersal events from South America coincided with formation of the Isthmus of Panama during the Pliocene. We elevate the subgenus Craugastor to the genus rank.

Among direct-developing rain frogs of the genus Craugastor is a clade of 19 described species (bocourti series) that occur in Mexico and northern Central America. Many of these 19 species have been described based on subtle morphological differences and have never been examined using molecular data. Here, we used a multilocus dataset (one mitochondrial (mtDNA) and four nuclear (nDNA) gene fragments, totalling 3,048 concatenated base pairs) to investigate species limits and phylogenetic relationships among 60 northern rain frogs referable to 12 species, with a focus on species from Guatemala. We inferred phylogenies using maximum likelihood and Bayesian analyses on separate mtDNA and nDNA datasets. Concatenated and coalescent species-tree analyses support the monophyly of multiple species, with interspecific relationships mostly unresolved. These mtDNA and nDNA trees were often incongruent with morphology-based taxonomy. For example, two genetically shallow clades contained individuals referable to at least five described species, whereas a single described species contained deep divergences indicative of multiple cryptic species. These findings indicate that morphology-based taxonomy has both overestimated and underestimated actual species diversity (depending on the species), an interpretation supported by two molecular species-delimitation procedures. Based on these findings, we synonymise C. glaucus (Lynch, 1967) and C. stuarti (Lynch, 1967) with C. xucanebi (Stuart, 1941). We also synonymise C. nefrens (Smith, 2005) and C. cyanochthebius McCranie & Smith, 2006 with C. campbelli (Smith, 2005). The molecular data also support multiple undescribed species, notably within C. decoratus (Taylor, 1942). Overall, we show how morphology-based species delimitation can both underestimate and overestimate species richness in morphologically conservative groups. [ABSTRACT FROM AUTHOR]

We present a taxonomic review and systematic revision of the Eyelash Palm-Pitviper Bothriechis schlegelii (Berthold, 1846) based on examination of 400 museum specimens, a phylogeographic analysis of 818 locality records, and 80 individuals sampled for molecular characters. We find morphological and phylogenetic support for five new species of Bothriechis Peters, 1859, which we describe here based on their unique combination of molecular, meristic, hemipenial, and color pattern characteristics. They are: B. klebbai sp. nov., B. rasikusumorum sp. nov., B. khwargi sp. nov., B. rahimi sp. nov., and B. hussaini sp. nov. Finally, we revalidate the names B. nigroadspersus (Steindachner, 1870), B. nitidus (Günther, 1859), and B. torvus (Posada Arango, 1889a), and provide a redescription of B. schlegelii. [ABSTRACT FROM AUTHOR]

We review morphology of Sunda Shelf Gonocephalus with an emphasis on Sumatran and Javan species. At least 15 species and subspecies inhabit Peninsular Malaysia, Sumatra, Java, Borneo, and adjacent smaller continental islands. Following analysis of external morphology, we provide a dichotomous key to Sunda Shelf Gonocephalus and resolve two taxonomic problems with this group of lizards. Three populations of Gonocephalus doriae on Borneo, Peninsular Malaysia, and Sumatra are recognized as subspecies, because they lack concordance of multiple morphological differences and have low genetic divergence in a 556 base-pair fragment of the 16S rRNA gene. Described as new herein, G. doriae brevis from Aceh and North Sumatra differs from G. d. abbotti and G. d. doriae in usually having more scales around midbody and a relatively shorter tail with fewer dark bands. Though previously reported as lost, a syntype of G. d. doriae (MSNG 29152) is designated as lectotype, illustrated, and described. Also described as new, G. inauris from high elevations of the Bukit Barisan Range of Bengkulu, Sumatra, is a species of the G. megalepis Group differing from all congeners in having 7/6 (vs. 8–19) loreals separating the last canthal and supralabials, 8/8 (11–27) infraorbitals, and 58 (73–153) scales around midbody. In this new species, distinctly enlarged suboculars broadly contact its supralabials, whereas 1–4 lorilabials separate the suboculars and supralabials in congeners. High genetic divergence in the new species mirrors its high level of morphological divergence. [ABSTRACT FROM AUTHOR]

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Lizards of the genus Dendragama are endemic to the highland cloud forests of Sumatra's Barisan Mountain Range in western Indonesia, and recent studies have uncovered widespread diversity within the genus. Here, a suite of morphological characters and mitochondrial DNA are used to compare three geographically isolated populations of D. boulengeri from (1) Mount Kerinci in Jambi province, (2) Mount Marapi of west Sumatra, and (3) the Karo Highlands of north Sumatra. Additional phylogeographic analyses with two recently described sister species, D. australis and D. dioidema were conducted. Five genetically distinct clades of Dendragama, all distributed allopatrically of one another were identified and some are suspected to inhabit small distributions. Morphological and genetic data confirm the Karo Highlands population D. schneideri (previously Acanthosaura schneideri Ahl, 1926) should be revalidated from the synonymy of D. boulengeri. Dendragama schneideri is endemic to montane forests of the Karo Highlands surrounding Lake Toba in Sumatra Utara province. Pairwise genetic distances of 6-11% separate D. schneideri from congeners. Two distinct clades of D. boulengeri from Mount Kerinci and Mount Marapi were identified, which are 5.0% genetically distant from one another. Using morphological characters, we provide the first key for distinguishing between species of Dendragama. Based on biogeographic patterns and levels of genetic variation it is suspected that at least 18 other isolated cloud forest locations may hold new species or divergent populations of Dendragama but lack survey work. Collectively, these comparisons among populations of montane lizards further elucidate the complex biogeographic history of Sumatra's montane forest species and the first phylogeny of the genus Dendragama. [ABSTRACT FROM AUTHOR]

We review morphology and systematics of Phoxophrys using new specimens of previously rare species. In addition to external characters, we relied heavily on skull morphology visualized using computed tomography data of all currently recognized species in this genus. Phylogenetic analysis of ND4, 12S, and 16S mDNA sequences reveal that Ph. tuberculata is sister to a clade containing Dendragama, Lophocalotes, and insular Pseudocalotes. Phoxophrys tuberculata is only distantly related to Bornean congeners. Phylogenetic analysis of 29 morphological characters scored for all the species of Phoxophrys and a diverse set of 22 outgroup taxa found four well-supported lineages: Ph. tuberculata, a clade of all Bornean congeners, Ph. nigrilabris, and a clade of the four large Bornean species. To resolve paraphyly of Phoxophrys, we revalidate Pelturagonia Mocquard for all Bornean species of this genus. As redefined, Phoxophrys contains a single species: Ph. tuberculata of Sumatra. We describe a new species of Pelturagonia from the Meratus Range of southeastern Kalimantan. The new species is the sister species of Pe. spiniceps. Like that species, it differs from congeners in having large, dorsally projecting scales between the dorsolateral caudal crests and a postorbital process of the frontal bone reaching the postciliary ornament. [ABSTRACT FROM AUTHOR]

We describe a new species of frog in the microhylid genus Micryletta Dubois, 1987 from Northeast India based on molecular and morphological evidence. The new species, formally described as Micryletta aishani sp. nov., is phenotypically distinct from other congeners by a suite of morphological characters such as brown to reddish-brown dorsum; dorsal skin shagreened with minute spinules; snout shape nearly truncate in dorsal and ventral view; a prominent dark streak extending from tip of the snout up to the lower abdomen; ash-grey mottling along the margins of upper and lower lip extending up to the flanks, limb margins and dorsal surfaces of hand and foot; tibiotarsal articulation reaching up to the level of armpits; absence of outer metatarsal tubercles; and absence of webbing between toes. Phylogenetic relationships within the genus are inferred based on mitochondrial data and the new taxon is found to differ from all the recognised Micryletta species by 3.5–5.9% divergence in the mitochondrial 16S rRNA. The new species was found in the states of Assam, Manipur, and Tripura, from low to moderate elevation (30–800 m asl) regions lying south of River Brahmaputra and encompassing the Indo-Burma Biodiversity Hotspot. The discovery validates the presence of genus Micryletta in Northeast India based on genetic evidence, consequently confirming the extension of its geographical range, westwards from Southeast Asia up to Northeast India. Further, for nomenclatural stability of two previously known species, Microhyla inornata (= Micryletta inornata) and Microhyla steinegeri (= Micryletta steinegeri), lectotypes are designated along with detailed descriptions. [ABSTRACT FROM AUTHOR]

A new species of frog in the genus Microhyla is described from Sumatra, Indonesia based on molecular and morphological characters. This new species was previously confused with M. achatina, a Javan endemic. This new species is diagnosable from its congeners by possessing a medium size (SVL in adult males 18.20-21.32 mm, in adult females 20.37-25.51 mm), a stout body, a nostril-eyelid length being about half of the snout length, having a single outer palmar tubercle, a tibiotarsal articulation reaching the center of the eye (when the hindlimbs are stretched and adpressed to the body), having finger and toe tips dilated, having the dorsum with medial longitudinal grooves, and excibiting a very thin and short dark stripe on the temporal region above a wider cream stripe, extending from the postorbital area to insertion of forelimb. Additionally, the new species is characterized by possessing relatively little foot webbing. Uncorrected 16S rRNA sequence divergences between the new taxon and sequences for other congeneric species available ranged from 4.8 to 15.0%. [ABSTRACT FROM AUTHOR]

We conduct species delimitation of the widespread parachuting frog species Rhacophorus catamitus using samples from across the island of Sumatra, Indonesia. We use mitochondrial, genomic and morphological data, and find that R. catamitus is composed of three lineages corresponding to northern, central and southern lineages. Mitochondrial and genomic data show admixture or incomplete lineage sorting between the central and southern lineages, but deep divergence from the northern lineage. Coalescent species delimitation supports a three species model for this complex, and we recommend that the northern lineage be described as a new species. Our study highlights the power of coalescent species delimitation in an integrative framework for identifying unrecognised diversity in understudied tropical species complexes. We also emphasise the evolutionary importance of northern Sumatra, a region that harboured montane refugia during Pliocene-Pleistocene climate change, but has also been heavily affected by volcanic activity. [ABSTRACT FROM AUTHOR]

We describe a new species of Cnemaspis from southern Sumatra, Indonesia. The new species is the first Cnemaspis reported from Sumatra and is a large (52.6-58.7 mm in snout-vent length [SVL]) nocturnal species. A combination of the following characters distinguishes the new species from all other Southeast Asian congeners: adults reaching 58.7 mm SVL; supralabials 13 or 14; infralabials 11 or 12; tricarinate ventrals; precloacal pores absent; moderately prominent, randomly arranged, dorsal tubercles; 20 or 21 paravertebral tubercles; no tubercles on lower flanks; caudal tubercles encircling tail; subcaudals keeled; the median row of subcaudals not enlarged; two postcloacal tubercles on each side of tail base; no enlarged femoral, subtibial, or submetatarsal scales; subtibial scales keeled; 28-34 subdigital lamellae on fourth toe; dark and light caudal bands distinct in both sexes. We tentatively assign the new species to the Cnemaspis kendallii group of the Southern Sunda clade of recent phylogenetic analyses. [ABSTRACT FROM AUTHOR]

Abstract: The venoms of coral snakes (genus Micrurus) are known to induce a broad spectrum of pharmacological activities. While some studies have investigated their potential human effects, little is known about their mechanism of action in terms of the ecological diversity and evolutionary relationships among the group. In the current study we investigated the neuromuscular blockade of the venom of two sister species Micrurus mipartitus and Micrurus dissoleucus, which exhibit divergent ecological characteristics in Colombia, by using the chick biventer cervicis nerve-muscle preparation. We also undertook a phylogenetic analysis of these species and their congeners, in order to provide an evolutionary framework for the American coral snakes. The venom of M. mipartitus caused a concentration-dependant inhibition (3–10 μg/ml) of nerve-mediated twitches and significantly inhibited contractile responses to exogenous ACh (1 mM), but not KCl (40 mM), indicating a postsynaptic mechanism of action. The inhibition of indirect twitches at the lower venom dose (3 μg/ml) showed to be triphasic and the effect was further attenuated when PLA2 was inhibited. M. dissoleucus venom (10–50 μg/ml) failed to produce a complete blockade of nerve-mediated twitches within a 3 h time period and significantly inhibited contractile responses to exogenous ACh (1 mM) and KCl (40 mM), indicating both postsynaptic and myotoxic mechanisms of action. Myotoxic activity was confirmed by morphological studies of the envenomed tissues. Our results demonstrate a hitherto unsuspected diversity of pharmacological actions in closely related species which exhibit divergent ecological characteristics; these results have important implications for both the clinical management of Coral snake envenomings and the design of Micrurus antivenom. [Copyright &y& Elsevier]

As most recently recognized, the name Cerrophidion barbouri Dunn, 1919, refers to a highland species of pitviper endemic to Guerrero, Mexico, of which Agkistrodon browni Shreve, 1938, is considered a junior synonym. This species is rarely collected and prior to recent decades it was known from only a few specimens. A careful re-examination of nearly all known specimens of C. barbouri and the type series of A. browni reveals that both names represent valid species and we therefore resurrect A. browni. Both species are extremely variable with respect to cephalic scalation and colour pattern, which has previously confounded efforts to identify them. We provide phylogenetic analyses using both Bayesian and maximum parsimony criteria of New World pitvipers to investigate the phylogenetic position of A. browni and C. barbouri. Our phylogenetic tree, based on 2235 bp of mitochondrial data [12S, 16S, cytochrome b (cyt b), NADH dehydrogenase subunit 4 (ND4)], strongly supports a clade consisting of A. browni, C. barbouri, and Ophryacus melanurus, which has a distant sister relationship to Ophryacus undulatus. Based on the deep phylogenetic divergences amongst these species and distinctive morphology we recommend that a new genus be recognized for A. browni, C. barbouri, and O. melanurus. Finally, we revise the genera Cerrophidion and Ophryacus in accordance with our new classification. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, 943-958. [ABSTRACT FROM AUTHOR]

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The snake family Elapidae contains over 60 genera (about 300 species) of highly venomous snakes. About one-third of the alpha-taxonomic diversity of the Elapidae comprises coralsnakes: a major radiation of colourful venomous snakes including six genera distributed in Asia and the Americas. In this study, we examine molecular phylogenetic and descriptive morphological evidence for the placement of the monotypic coralsnake genus Hemibungarus ( H. calligaster (Wiegmann)) among the elapids, and clarify the relationships among genera traditionally referred to as ‘coralsnakes’. We use two mitochondrial gene fragments (ND4 and cyt- b) and a nuclear gene fragment (c-mos) to estimate relationships among elapids and other colubroid snakes, based on parsimony and likelihood methods, as well as Bayesian phylogenetic methods incorporating complex partitioned models of nucleotide evolution. As different phylogenetic methods provided alternativee results, we include an extensive examination of molecular phylogenetic analyses to facilitate a transparent and thorough exploration of the data. Additionally, we highlight external morphological and hemipenial characters that appear to further support molecular hypotheses for the placement of Hemibungarus, and relationships among the Elapinae. Owing to conflicting descriptions of morphological characters in the literature, and the unavailable of comparative morphological data for certain key species, we include detailed descriptions of the hemipenes of Bungarus caeruleus (Schneider), B. fasciatus (Schneider), Calliophis nigrescens Günther, Dendroaspis polylepis (Günther), H. calligaster (Wiegmann), Naja naja (Linnaeus) and Ophiophagus hannah (Cantor). We present evidence that Asian and American coralsnakes ( Calliophis, Sinomicrurus, Micruroides, Micrurus and Leptomicrurus) form an exclusive clade, distantly related to Hemibungarus. Thus, despite long-held beliefs of systematic affinities based on morphology and colour pattern, our results suggest that Hemibungarus is not (phylogenetically) a coralsnake, but instead shares an exclusive common ancestor with Afro-Asian elapine genera ( Elapsoidea, Dendroaspis and Ophiophagus). Results of our molecular phylogenetic analyses also support the recognition of two primary clades of elapids corresponding to the subfamilies Elapinae and Hydrophiinae. Additionally, we provide evidence that the Elapinae consists of two main clades: (1) coralsnakes s.s. ( Calliophis, Sinomicrurus, Micruroides, Micrurus, Leptomicrurus), and (2) the remaining genera of Afro-Asian species, including cobras, kraits, mambas and Hemibungarus. We suggest a new classification for these two elapine clades: Calliophini for the coralsnakes ( Calliophis, Sinomicrurus, Micrurus, Micruroides and Leptomicrurus), and Hemibungarini for the remaining Afro-Asian elapine species, including Hemibungarus. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 151, 809–831. [ABSTRACT FROM AUTHOR]