Possible osteosarcoma reported from a new world elapid snake and review of reptilian bony tumors.

Cancer chiefly occurs in vertebrates. Rare in amphibians, and perhaps common in reptiles, various neoplasms and malignant cancers have been reported with erratic frequency by museums, paleontologists, veterinarians, and pet hobbyists. Unsurprisingly, most herpetofaunal diversity has never been systematically surveyed for the presence of neoplasms owing to the extreme rarity or obscurity of many species. Museum collections can fill these gaps in knowledge, especially when researchers use non-destructive techniques. In this study, we used X-ray computed tomography (CT) to discover and characterize a possible osteosarcoma of the spine in a rare South American coralsnake, Micrurus ancoralis. Two spinal vertebrae were completely fused and adjacent vertebrae showed evidence of corruption. The fused vertebrae contained a hollow inner network thought to be vascular tissue. We also review previous reports of neoplasms in the Elapidae and all bony neoplasms in non-avian reptiles. The rarely reported technique of X-ray CT for tumor discovery could greatly improve our understanding of the species diversity and perhaps underlying causes of neoplasia.

A new species of Pseudocalotes (Squamata: Agamidae) from the Bukit Barisan Range of Sumatra with an Estimation of its phylogeny.

We describe a new species of Pseudocalotes from montane forests of the central, western coast of Sumatra. The combination of 3 or 4 interoculabials, slightly enlarged and heavily keeled scales on the lower flanks, a white scapular spot, a relatively long fifth toe, bicarinate lamellae at the base of Toe III, absence of a postrictal modified scale, and three rows of paravertebrals directed dorsally and posteriorly distinguishes the new species from its congeners on Sumatra and Java. Among the new characters defined in this study, counts of subdigital lamellae within the "span of Toe V" proved particularly useful for diagnosing species of Pseudocalotes. Phylogenetic analysis of DNA sequences identified a monophyletic group containing the Sumatran and Javan Pseudocalotes. Based on the phylogeny, we define a P. cybelidermus Group containing P. cybelidermus and P. guttalineatus and a P. tympanistriga Group containing P. tympanistriga, P. rhammanotus, and the new species. Combinations of five morphological characters define each of these two clades. As currently defined, Pseudocalotes is polyphyletic; Javan and Sumatran species are more closely related to other draconines such as Dendragama boulengeri than they are to some mainland species.

Isolation, characterization, cloning and expression of an alpha-neurotoxin from the venom of the Mexican coral snake Micrurus laticollaris (Squamata: Elapidae).

A new member of short chain α-neurotoxic protein family from venom of the Mexican coral snake, Micrurus laticollaris, was characterized. This protein, named MlatA1, possesses 61 amino acids with 8 conserved cysteine residues, sharing 30-91% sequence identity with other fully sequenced Micrurus toxins. MlatA1 (LD50i.v. = 0.064 mg/kg) antagonizes with both fetal and adult nicotinic acetylcholine receptor (nAChR) as well as α-7 neuronal nAChR in a dose-dependent way. Specific rabbit anti-Mlat serum (titer higher than 18,000) does not show any protective ability against this toxin, nevertheless it was able to recognize protein bands in six out of twelve Micrurus venoms showing the existence of two distinct antigenic groups for α-neurotoxins in North American coral snakes species. The MlatA1 gene was cloned and used to produce recombinant toxin (rMlatA1) that was recognized by rabbit anti-native toxin but was depleted of toxic activity.

Rampant horizontal transfer of SPIN transposons in squamate reptiles.

Transposable elements (TEs) are highly abundant in the genome and capable of mobility, two properties that make them particularly prone to transfer horizontally between organisms. Although the impact of horizontal transfer (HT) of TEs is well recognized in prokaryotes, the frequency of this phenomenon and its contribution to genome evolution in eukaryotes remain poorly appreciated. Here, we provide evidence that a DNA transposon called SPIN has colonized the genome of 17 species of reptiles representing nearly every major lineage of squamates, including 14 families of lizards, snakes, and amphisbaenians. Slot blot analyses indicate that SPIN has amplified to high copy numbers in most of these species, ranging from 2,000-28,000 copies per haploid genome. In contrast, we could not detect the presence of SPIN in any of the turtles (seven species from seven families) and crocodiles (four species) examined. Genetic distances between SPIN sequences from species belonging to different squamate families are consistently very low (average = 0.1), considering the deep evolutionary divergence of the families investigated (most are >100 My diverged). Furthermore, these distances fall below interfamilial distances calculated for two genes known to have evolved under strong functional constraint in vertebrates (RAG1, average = 0.24 and C-mos, average = 0.27). These data, combined with phylogenetic analyses, indicate that the widespread distribution of SPIN among squamates is the result of at least 13 independent events of HTs. Molecular dating and paleobiogeographical data suggest that these transfers took place during the last 50 My on at least three different continents (North America, South America and, Africa). Together, these results triple the number of known SPIN transfer events among tetrapods, provide evidence for a previously hypothesized transoceanic movement of SPIN transposons during the Cenozoic, and further underscore the role of HT in the evolution of vertebrate genomes.

Complex evolution in the Neotropics: the origin and diversification of the widespread genus Leptodeira (Serpentes: Colubridae).

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.

Cenozoic biogeography and evolution in direct-developing frogs of Central America (Leptodactylidae: Eleutherodactylus) as inferred from a phylogenetic analysis of nuclear and mitochondrial genes.

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.

A new species of Osteocephalus (Anura: Hylidae) from Guyana

A new member of the genus Osteocephalus is described from the Pakaraima mountains of western Guyana. This species is the smallest known member of the genus and is probably closely related to O. subtilis. Both share a small size (less than 40 mm snout-vent length), large and bulgy eyes directed somewhat rostrally, green bones, smooth and brownish dorsal skin, relatively short and truncate snout, small tympanum, subgular and laterally expanded vocal sac, poorly developed subarticular and supernumerary tubercles, a supra-anal glandular ridge, and cream-white venter and subocular region. The new species can be distinguished from O. subtilis by the Buff iris (vs black), smaller overall size (32.7 vs 35.8-38.8 mm snout-vent length), relatively larger toe disks, and less developed foot webbing. The cranium of the new species is well ossified, relatively reduced in width between the orbits, without an exposed frontoparietal fontanelle and with the anterior arm of the squamosal extending to about half the distance to the maxillary. The vocal sac is subgularly poorly developed and possess lateral extensions to the area behind the jaw angles. Well developed supraocular and suprasquamosal cartilages give support to the enlarged eyes of this species.

A new species of arboreal pitviper from the Atlantic versant of northern Central America

A new species of green, prehensile-tailed pitviper of the genus Bothriechis is described from the Atlantic slopes of eastern Guatemala and western Honduras. This species appears to be most closely related to B. bicolor of the Pacific versant of Chiapas (Mexico) and Guatemala. Several other species of Bothriechis occur on the Atlantic versant of northern Central America, including two montane species, B. aurifer and B. marchi but, with one possible exception, these are not known to be sympatric with the new species and occur in different mountain ranges. The widespread B. schlegelii occurs up to at least 900 m on the Sierra de Caral, where the lowest elevation recorded for the new species is 885 m.