2016-12-23T18:52:10

Caenophidian snakes include the file snake genus Acrochordus and advanced colubroidean snakes that radiated mainly during the Neogene. Although caenophidian snakes are a well-supported clade, their inferred affinities, based either on molecular or morphological data, remain poorly known or controversial. Here, we provide an expanded molecular phylogenetic analysis of Caenophidia and use three non-parametric measures of support–Shimodaira-Hasegawa-Like test (SHL), Felsentein (FBP) and transfer (TBE) bootstrap measures–to evaluate the robustness of each clade in the molecular tree. That very different alternative support values are common suggests that results based on only one support value should be viewed with caution. Using a scheme to combine support values, we find 20.9% of the 1265 clades comprising the inferred caenophidian tree are unambiguously supported by both SHL and FBP values, while almost 37% are unsupported or ambiguously supported, revealing the substantial extent of phylogenetic problems within Caenophidia. Combined FBP/TBE support values show similar results, while SHL/TBE result in slightly higher combined values. We consider key morphological attributes of colubroidean cranial, vertebral and hemipenial anatomy and provide additional morphological evidence supporting the clades Colubroides, Colubriformes, and Endoglyptodonta. We review and revise the relevant caenophidian fossil record and provide a time-calibrated tree derived from our molecular data to discuss the main cladogenetic events that resulted in present-day patterns of caenophidian diversification. Our results suggest that all extant families of Colubroidea and Elapoidea composing the present-day endoglyptodont fauna originated rapidly within the early Oligocene–between approximately 33 and 28 Mya–following the major terrestrial faunal turnover known as the “Grande Coupure” and associated with the overall climate shift at the Eocene-Oligocene boundary. Our results further suggest that the caenophidian radiation originated within the Caenozoic, with the divergence between Colubroides and Acrochordidae occurring in the early Eocene, at ~ 56 Mya.

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We describe two new species of the Cyrtodactylus irregularis complex both based on phylogenetic analysis of 654 bp of COImtDNA gene and morphological analyses of voucher specimens from Binh Phuoc and Lam Dong provinces, southern Vietnam.Cyrtodactylus bugiamapensis sp. nov. is described from the monsoon tropical forests of Bu Gia Map National Park, BinhPhuoc Province, and is distinguished from the remaining representatives of the C. irregularis complex by a combination of thefollowing characters: (1) size medium, with a maximum SVL of 76.8 mm; (2) original tail relatively thin, longer than body; (3)presence of enlarged femoral scales without femoral pores; (4) preclocal groove lacking; (5) 36–46 longitudinal rows of ventralscales at midbody; (6) males with 7–11 precloacal pores in an angular continuous series; (7) absence of enlarged subcaudals;(8) dorsal pattern consisting of a dark neck band which can be medially divided, and irregular dark brown spots with brightwhite edges. Cyrtodactylus bidoupimontis sp. nov. is described from mountainous evergreen tropical forests of Bidoup – NuiBa National Park, Lam Dong Province, and is most similar to C. irregularis sensu stricto from which it is distinguished by acombination of the following characters: (1) absence of enlarged, strongly keeled conical tubercles on the dorsal tail-base; (2)presence of flat rounded smooth to weakly keeled dorsal tubercles; (3) pallid dorsal head surface pattern lacking distinct darkbrown irregular spots with light edges; and (4) elongated limbs. Phylogenetic analyses revealed the presence of a number ofcryptic allopatric species within the C. irregularis complex. Long geological history and complicated relief of the Lang Bianplateau and surrounding areas might have shaped the present diversity within the C. irregularis complex. COI DNA-barcoding appears to be a useful tool to reveal cryptic diversity within the genus Cyrtodactylus.

Southeast Asia and southern China (SEA-SC) harbor a highly diverse and endemic flora and fauna that is under increasing threat. An understanding of the biogeographical history and drivers of this diversity is lacking, especially in some of the most diverse and threatened groups. The Asian leaf-litter frog genus Leptolalax Dubois 1980 is a forest-dependent genus distributed throughout SEA-SC, making it an ideal study group to examine specific biogeographic hypotheses. In addition, the diversity of this genus remains poorly understood, and the phylogenetic relationships among species of Leptolalax and closely related Leptobrachella Smith 1928 remain unclear. Herein, we evaluate species-level diversity based on 48 of the 53 described species from throughout the distribution of Leptolalax. Molecular analyses reveal many undescribed species, mostly in southern China and Indochina. Our well-resolved phylogeny based on multiple nuclear DNA markers shows that Leptolalax is not monophyletic with respect to Leptobrachella and, thus, we assign the former to being a junior synonym of the latter. Similarly, analyses reject monophyly of the two subgenera of Leptolalax. The diversification pattern of the group is complex, involving a high degree of sympatry and prevalence of microendemic species. Northern Sundaland (Borneo) and eastern Indochina (Vietnam) appear to have played pivotal roles as geographical centers of diversification, and paleoclimatic changes and tectonic movements seem to have driven the major divergence of clades. Analyses fail to reject an "upstream" colonization hypothesis, and, thus, the genus appears to have originated in Sundaland and then colonized mainland Asia. Our results reveal that both vicariance and dispersal are responsible for current distribution patterns in the genus.

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