We carried out a taxonomic revision of Ahaetulla species inhabiting Peninsular India, using a multiple criteria approach (including genetics, morphology, and geography). Our work included populations of the A. nasuta complex (widespread across the entire region, including the Western Ghats), the A. pulverulenta complex (in the Western Ghats, within Peninsular India) and the A. dispar complex (endemic to the Southern Western Ghats) which all revealed undocumented cryptic diversity. Here, we describe five new species and effect nomenclatural changes to some recognised taxa. In the A. nasuta complex, we describe four species from several latitudinal blocks of the Western Ghats and make nomenclatural emendations to the plains populations in the Indian peninsula. We effect nomenclatural change in the A. pulverulenta population of the Western Ghats and describe a new species from the A. dispar group. Our study highlights the use of a multi-criteria approach in unraveling cryptic diversity. This study also reveals a striking case of discordance between morphological and genetic divergence, and the way this is reflected in previous taxonomic and nomenclatural treatments of these populations.
Asian pit vipers belonging to the genus Craspedocephalus are a complex group of vipers, distributed in South and Southeast Asia. Their taxonomy is unresolved in many lineages across their distributional range. Here, we reassess the taxonomy and systematics of pit vipers of the genus Craspedocephalus in Peninsular India based on extensive field sampling, in particular in the Western Ghats. We build and expand on the previous findings of genetic relatedness between the peninsular Indian lineages with the Sundaic clade (C. puniceus complex) with greater evidence, based on additional taxa sequenced herein. We reconstruct the phylogeny of the group using three mitochondrial genes and delineated lineages using coalescent species delimitation methods. We then used multiple criteria including genetic divergence and separation in morphological and geographic space to designate taxonomic units. Our work revealed the presence of a South Asian radiation of the clade Craspedocephalus, with a few Sundaic members. Our study reveals the systematic relationships of four Peninsular Indian species of Craspedocephalus, including Peltopelor macrolepis and C. strigatus, sequenced here for the first time, that are classified or confirmed as members of Craspedocephalus. Hence, we place the genus Peltopelor in the synonymy of Craspedocephalus. Using our multi-criteria approach, we delimit four new cryptic evolutionary lineages within the Western Ghats escarpment of Peninsular India. These cryptic lineages belong to the C. malabaricus, C. gramineus and C. macrolepis complexes and are geographically and/or ecologically (in terms of habitat association) distinct from their sister lineages across their distributional range, while others are separated in morphological space. Our new phylogenetic tree and delimitation analysis thus reveals the presence of multiple clades with several cryptic lineages separated by geographical barriers or habitat association.
We conducted a molecular phylogenetic study on the Boiga ceylonensis group from the Western Ghats of India, building on a recent morphology-based study. Our analysis supports previous work in elucidating the phylogenetic position of B. nuchalis and B. beddomei s. str. (of Matheran, Western Ghats) as clustering closely with B. ceylonensis, while B. flaviviridis clustered with the Sri Lankan taxon close to B. ranawanei. Additionally, our phylogenetic study revealed the presence of an undescribed taxon in the Southern Western Ghats, more closely related to B. ceylonensis than to any other sampled taxon, including sympatric congeners. This new taxon is described here as a new species Boiga whitakeri sp. nov. from the Devar Malai–Anaimalai hill complex. Based on molecular and morphometric studies, we expand the description of the recently described B. thackerayi as inhabiting almost the entire stretch of the Western Ghats. We also complement the diagnoses of B. nuchalis and B. flaviviridis, and determine the phylogenetic position of B. thackerayi with molecular data.
The Western Ghats are well known as a biodiversity hotspot, but the full extent of its snake diversity is yet to be uncovered. Here, we describe a new genus and species of vine snake
Proahaetulla antiqua
gen. et sp. nov
., from the Agasthyamalai hills in the southern Western Ghats. It was found to be a member of the Ahaetuliinae clade, which currently comprises the arboreal snake genera
Ahaetulla
,
Dryophiops
,
Dendrelaphis
and
Chrysopelea
, distributed in South and Southeast Asia.
Proahaetulla
shows a sister relationship with all currently known taxa belonging to the genus
Ahaetulla
, and shares ancestry with
Dryophiops
. In addition to its phylogenetic position and significant genetic divergence, this new taxon is also different in morphology from members of Ahaetuliinae in a combination of characters, having 12–13 partially serrated keels on the dorsal scale rows, 20 maxillary teeth and 3 postocular scales. Divergence dating reveals that the new genus is ancient, dating back to the Mid-Oligocene, and is one of the oldest persisting monotypic lineages of snakes in the Western Ghats. This discovery adds to the growing list of ancient lineages endemic to the Agasthyamalai hills and underscores the biogeographic significance of this isolated massif in the southern Western Ghats.
We revisit the identities of ‘Trimeresurus albolabris’ records from India and Nepal, based on a re-examination of historically mentioned specimens. Based on morphological congruence, we identify an old specimen originally labeled as T. albolabris from ‘Nagpur, Central Province’ as Trimeresurus salazar. We also provide new records of T. salazar based on molecular data from newly collected specimens in Central India. As the range of T. salazar is now known to approach that of its sister species Trimeresurus septentrionalis, we also redescribe T. septentrionalis based on the holotype and referred material. Finally, we examined two historical specimens from “Madras” collected during the Novara Expedition, which we identify as T. davidi, leading to a reassessment of their origin. Consequently, we remove T. albolabris from the list of Indian snake fauna.
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