Their fates intertwined: diversification patterns of the Asian gliding vertebrates may have been forged by dipterocarp trees.

The repeated evolution of gliding in diverse Asian vertebrate lineages is hypothesized to have been triggered by the dominance of tall dipterocarp trees in the tropical forests of Southeast Asia. These dipterocarp forests have acted as both centres of diversification and climatic refugia for gliding vertebrates, and support most of their extant diversity. We predict similarities in the diversification patterns of dipterocarp trees and gliding vertebrates, and specifically test whether episodic diversification events such as rate shifts and/or mass extinctions were temporally congruent in these groups. We analysed diversification patterns in reconstructed timetrees of Asian dipterocarps, the most speciose gliding vertebrates from different classes (Draco lizards, gliding frogs and Pteromyini squirrels) and compared them with similar-sized clades of non-gliding relatives (Diploderma lizards, Philautus frogs and Callosciurinae squirrels) from Southeast Asia. We found significant declines in net-diversification rates of dipterocarps and the gliding vertebrates during the Pliocene-Pleistocene, but not in the non-gliding groups. We conclude that the homogeneity and temporal coincidence of these rate declines point to a viable ecological correlation between dipterocarps and the gliding vertebrates. Further, we suggest that while the diversification decay in dipterocarps was precipitated by post-Miocene aridification of Asia, the crises in the gliding vertebrates were induced by both events concomitantly.

Eocene-Oligocene cooling and the diversification of Hemidactylus geckos in Peninsular India.

The Eocene-Oligocene cooling marks a global shift towards a cooler and drier climate, concurrent with significant turnover in biota globally. In Peninsular India, palynological investigations suggest a shift from wet rainforest vegetation to dry and seasonal species during this period. However, the grassland and open habitats that dominate this region at present expanded relatively recently due to Late Miocene intensification of monsoon seasonality. We test the possible role of these climatic shifts in generating the dry habitat diversity of an endemic radiation of Hemidactylus geckos distributed in both wet and dry habitats, by investigating whether (a) the beginning of the diversification of dry habitat lineages overlap with the Eocene-Oligocene cooling or late Miocene aridification and (b) accompanied by an increase in diversification. Molecular data (two nuclear and two mitochondrial gene fragments) were generated for samples collected across Peninsular India, and along with previously published data, a time-calibrated phylogeny was reconstructed. Ancestral state reconstruction of dry and wet habitat states was carried out on the time-calibrated phylogeny and γ-statistics along with a test for diversity-dependent diversification utilized to examine the trend in lineage accumulation. Results show the ancestral node of this radiation to have a dry habitat state, which began diversifying between 39 and 32 million years ago, concurrent with the Eocene-Oligocene cooling. Furthermore, lineage diversification fit a diversity-dependent model of diversification and the γ-statistics revealed an early increase in diversification followed by a slowdown later. The deep divergences of dry habitat lineages concurrent with the Eocene-Oligocene cooling suggest that this could have served as an ecological opportunity facilitating an early increase in lineage diversification of Hemidactylus in this region. These results suggest an ancient origin and long persistence of arid ecosystems in Peninsular India.

Multilocus nuclear markers provide new insights into the origin and evolution of the blackbuck (Antilope cervicapra, Bovidae).

Evolutionary relationships between members of the Antilopina taxon have been much debated in recent years. The 'true antelope' clade is currently comprised of 4 genera viz., Gazella, Nanger, Eudorcas and the monotypic genus Antilope, that includes A. cervicapra. Most studies have focused on the mitochondrial genome or morphological data to study their relationships. However, signals from mitochondrial data can often be misleading when compared with nuclear markers, as has been shown in multiple taxonomic groups. In this study, we revisit the phylogenetic relationships among members of Antilopina, particularly the phylogenetic position of A. cervicapra, using 12 nuclear markers and compare it with the mitochondrial tree. Furthermore, we explore the implications of the results of this study on the taxonomy and biogeography of Indian antelopes. The nuclear phylogenetic trees built using multiple coalescent and concatenated methods all supported a paraphyletic genus Gazella. Antilope was nested within Gazella as opposed to being sister to it, which was suggested by previous studies and our results based on mitochondrial markers. Our fossil-calibrated larger bovid phylogeny, based on nuclear markers, suggested that the Antilope lineage diverged from its sister species more recently in the Pleistocene, rather than in late Miocene as per previous studies. Our biogeographic analyses suggest that the lineage leading to genus Antilope dispersed into India from the Saharo-Arabian realm around 2 mya, post the expansion of grasslands. We speculate that the adaptations of this savanna-grassland specialist did not allow them to extend their range beyond the Indian subcontinent. Whereas, the only other true antelope in India, G. bennetti, extended its range into India more recently, probably after the establishment of the Thar desert in northwest India.

Aridification driven diversification of fan-throated lizards from the Indian subcontinent.

The establishment of monsoon climate and the consequent aridification has been one of the most important climate change episodes in the Indian subcontinent. However, little is known about how these events might have shaped the diversification patterns among the widely distributed taxa. Fan-throated lizards (FTL) (Genus: Sitana, Sarada) are widespread, diurnal and restricted to the semi-arid zones of the Indian subcontinent. We sampled FTL in 107 localities across its range. We used molecular species delimitation method and delineated 15 species including six putative species. Thirteen of them were distinguishable based on morphology but two sister species were indistinguishable and have minor overlaps in distribution. Five fossils were used to calibrate and date the phylogeny. Diversification of fan-throated lizards lineage started ~18 mya and higher lineage diversification was observed after 11 my. The initial diversification corresponds to the time when monsoon climate was established and the latter was a period of intensification of monsoon and initiation of aridification. Thirteen out of the fifteen FTL species delimited are from Peninsular India; this is probably due to the landscape heterogeneity in this region. The species poor sister genus Otocryptis is paraphyletic and probably represents relict lineages which are now confined to forested areas. Thus, the seasonality led changes in habitat, from forests to open habitats appear to have driven diversification of fan-throated lizards.

Lizard Wears Shades. A Spectacled Sphenomorphus (Squamata: Scincidae), from the Sacred Forests of Mawphlang, Meghalaya, North-east India.

A new species of lygosomatine scincid lizard is described from the sacred forests of Mawphlang, in Meghalaya, northeastern India. Sphenomorphus apalpebratus sp. nov. possesses a spectacle or brille, an unusual feature within the Scincidae, and a first for the paraphyletic genus Sphenomorphus. The new species is compared with other members of the genus to which it is here assigned, as well as to members of the lygosomatine genera Lipinia and Scincella from mainland India, the Andaman and Nicobar Islands, and southeast Asia, to which it also bears resemblance. The new taxon is diagnosable in exhibiting the following combination of characters: small body size (SVL to 42.0 mm); moveable eyelids absent; auricular opening scaleless, situated in a shallow depression; dorsal scales show a line of demarcation along posterior edge of ventral pes; midbody scale rows 27-28; longitudinal scale rows between parietals and base of tail 62-64; lamellae under toe IV 8-9; supraoculars five; supralabials 5-6; infralabials 4-5; subcaudals 92; and dorsum golden brown, except at dorsal margin of lateral line, which is lighter, with four faintly spotted lines, two along each side of vertebral row of scales, that extend to tail base. The new species differs from its congeners in the lack of moveable eyelids, a character shared with several distantly related scincid genera.

A long-lost relic from the Eastern Ghats: Morphology, distribution and habitat of Sepsophis punctatus Beddome, 1870 (Squamata: Scincidae).

Sepsophis punctatus Beddome 1870, the only species of a monotypic genus, was described based on a single specimen from the Eastern Ghats of India. We rediscovered the species based on specimens from Odisha and Andhra Pradesh state, India, after a gap of 137 years, including four specimens from close to the type locality. The holotype was studied in detail, and we present additional morphological characters of the species with details on natural history, habitat and diet. The morphological characters of the holotype along with two additional specimens collected by Beddome are compared with the specimens collected by us. We also briefly discuss the distribution of other members of the subfamily Scincinae and their evolutionary affinities.

Geography vs. past climate: the drivers of population genetic structure of the Himalayan langur.

BACKGROUND: Contemporary species distribution, genetic diversity and evolutionary history in many taxa are shaped by both historical and current climate as well as topography. The Himalayas show a huge variation in topography and climatic conditions across its entire range, and have experienced major climatic fluctuations in the past. However, very little is known regarding how this heterogenous landscape has moulded the distribution of Himalayan fauna. A recent study examined the effect of these historical events on the genetic diversity of the Himalayan langurs in Nepal Himalaya. However, this study did not include the samples from the Indian Himalayan region (IHR). Therefore, here we revisit the questions addressed in the previous study with a near complete sampling from the IHR, along with the samples from the Nepal Himalaya. We used the mitochondrial Cytochrome-b (Cyt-b, 746 bp) region combined with multiple phylogeographic analyses and palaeodistribution modelling. RESULTS: Our dataset contained 144 sequences from the IHR as well as the Nepal Himalaya. Phylogenetic analysis showed a low divergent western clade nested within high divergent group of eastern lineages and in the network analysis we identified 22 haplotypes over the entire distribution range of the Himalayan langurs. Samples from the Nepal Himalaya showed geographically structured haplotypes corresponding to different river barriers, whereas samples from IHR showed star-like topology with no structure. Our statistical phylogeography analysis using diyABC supported the model of east to west colonisation of these langurs with founder event during colonisation. Analysis of demographic history showed that the effective population size of the Himalayan langurs decreased at the onset of last glacial maximum (LGM) and started increasing post LGM. The palaeodistribution modelling showed that the extent of suitable habitat shifted from low elevation central Nepal, and adjoining parts of north India, during LGM to the western Himalaya at present. CONCLUSION: The current genetic diversity and distribution of Himalayan langurs in the Nepal Himalaya has been shaped by river barriers, whereas the rivers in the IHR had relatively less time to act as a strong genetic barrier after the recent colonisation event. Further, the post LGM expansion could have had confounding effect on Himalayan langur population structure in both Nepal Himalaya and IHR.

Diversification in the mountains: a generic reappraisal of the Western Ghats endemic gecko genus Dravidogecko Smith, 1933 (Squamata: Gekkonidae) with descriptions of six new species.

The monotypic genus Dravidogecko, represented by its type-species D. anamallensis, is singular amongst peninsular Indian gekkonid lineages in its endemism to the Western Ghats. Molecular species delimitation approaches reveal at least seven species-level lineages within the genus from its distribution range across the mid-high elevations of the southern Western Ghats of India. These lineages, albeit superficially cryptic, are patently diagnosable from each other by employing a limited but precise set of morphological characters. Six of these lineages that were obscured under the nomen D. anamallensis are herein recognized as distinct species. A reappraisal of the genus Dravidogecko is provided based on external morphology and osteological characters, along with a detailed redescription of the holotype of D. anamallensis. A key to the species based on diagnostic characters is presented. Gene-trees based on mitochondrial and nuclear DNA data recovered marginally disparate topologies and were consequently coalesced into a species-tree for phylogenetic inference. Timetree analysis reveals late Miocene cladogenesis in this group and establishes late Palaeocene divergence from its sister genus, Hemidactylus, making Dravidogecko one of the earliest, extant lizard lineages to have colonized peninsular India.

On the systematic status of the genus Oriocalotes Günther, 1864 (Squamata: Agamidae: Draconinae) with the description of a new species from Mizoram state, Northeast India.

The montane agamid lizard genus Oriocalotes is currently considered monotypic, represented by the species, O. paulus. The systematic status of this taxon has remained questionable since its initial descriptions in the mid-1800s. A detailed molecular and morphological study was carried out to assess the validity of this genus, and its systematic position within the Asian agamid subfamily, Draconinae. Freshly collected and historical museum specimens from the type locality of O. paulus were examined morphologically, along with additional samples collected from localities in Mizoram state, Northeast India. Utilising newly generated molecular sequences (two mitochondrial and three nuclear genes), combined with those previously published for representative genera from the subfamilies Draconinae and Agaminae, Maximum Likelihood and Bayesian phylogenetic trees were constructed. Phylogenetic results suggest that Oriocalotes is part of the widespread South and Southeast Asian radiation of Calotes. Comparative morphological studies (including external morphology, hemipenis and osteology) between Oriocalotes and related genera further support this systematic placement. Oriocalotes is herein regarded as a junior subjective synonym of Calotes. Calotes paulus comb. nov. is also assigned a lectotype and given a detailed redescription based on the lectotype, paralectotypes and additional topotypic material. Furthermore, the specimens collected from Mizoram populations are found to be morphologically and genetically distinct from Calotes paulus comb. nov., and are described herein as a new species, Calotes zolaiking sp. nov.

Descriptions of two new endemic and cryptic species of Sitana Cuvier, 1829 from peninsular India.

Two new cryptic species of the agamid genus Sitana Cuvier, 1829 from Peninsular India are described herein. Sitana gokakensis sp. nov. from Gokak, Karnataka closely resembles Sitana thondalu sp. nov. from Nagarjuna Sagar, Andhra Pradesh. The two species can be distinguished based on their subtle morphological differences, genetic difference and geographic distribution. Sitana gokakensis sp. nov. have a relatively depressed head compared to Sitana thondalu sp. nov. Additionally, the vertebral scale counts differ in females of the two new species (Sitana gokakensis sp. nov. 45-47 vs Sitana thondalu sp. nov. 49-53). Genetic divergence between them is comparable to those between previously described Sitana species. Furthermore, the two new species are distributed ca. 500 km apart and are endemic to their respective landscapes that lie in similar latitudes of peninsular India. We urge the use of large sample size in new species descriptions especially those dealing with cryptic species like Sitana. The discovery of the two new cryptic species from these rocky terrains in peninsular India highlights need for more herpetological exploration in this region.

The curious case of Hemidactylus gujaratensis (Squamata: Gekkonidae).

Hemidactylus Oken, 1817 is one of the most speciose genera of the family Gekkonidae with more than 140 described species (Uetz et al. 2016). While this genus naturally occurs across the tropics and subtropics, a substantial part of its distribution also results from human-mediated dispersal. Carranza Arnold (2006) retrieved five broad clades in a global phylogeny of Hemidactylus, one of which has species distributed in tropical Asia. Subsequent work by Bauer et al. (2010) and Bansal Karanth (2010) revealed that the species from tropical Asia fell into two deeply divergent and potentially non-sister sub-clades-one comprising a large radiation confined to peninsular India and Sri Lanka (the Indian radiation, IR), and the other comprising species largely distributed in Southeast (SE) Asia.

Flying between sky islands: the effect of naturally fragmented habitat on butterfly population structure.

High elevation montane areas are called "sky islands" when they occur as a series of high mountains separated by lowland valleys. Different climatic conditions at high elevations makes sky islands a specialized type of habitat, rendering them naturally fragmented compared to more continuous habitat at lower elevations. Species in sky islands face unsuitable climate in the intervening valleys when moving from one montane area to another. The high elevation shola-grassland mosaic in the Western Ghats of southern India form one such sky island complex. The fragmented patches make this area ideal to study the effect of the spatial orientation of suitable habitat patches on population genetic structure of species found in these areas. Past studies have suggested that sky islands tend to have genetically structured populations, possibly due to reduced gene flow between montane areas. To test this hypothesis, we adopted the comparative approach. Using Amplified Fragment Length Polymorphisms, we compared population genetic structures of two closely related, similar sized butterfly species: Heteropsis oculus, a high elevation shola-grassland specialist restricted to the southern Western Ghats, and Mycalesis patnia, found more continuously distributed in lower elevations. In all analyses, as per expectation the sky island specialist H. oculus exhibited a greater degree of population genetic structure than M. patnia, implying a difference in geneflow. This difference in geneflow in turn appears to be due to the natural fragmentation of the sky island complexes. Detailed analysis of a subset of H. oculus samples from one sky island complex (the Anamalais) showed a surprising genetic break. A possible reason for this break could be unsuitable conditions of higher temperature and lower rainfall in the intervening valley region. Thus, sky island species are not only restricted by lack of habitat continuity between montane areas, but also by the nature of the intervening habitat.

Did southern Western Ghats of peninsular India serve as refugia for its endemic biota during the Cretaceous volcanism?

The Western Ghats (WG) of south India, a global biodiversity hotspot, has experienced complex geological history being part of Gondwana landmass and encountered extensive volcanic activity at the end of Cretaceous epoch. It also has a climatically and topographically heterogeneous landscape. Thus, the WG offer a unique setting to explore the influence of ecological and geological processes on the current diversity and distribution of its biota. To this end, three explicit biogeographical scenarios were hypothesized to evaluate the distribution and diversification of wet evergreen species of the WG - (1) southern WG was a refuge for the wet evergreen species during the Cretaceous volcanism, (2) phylogenetic breaks in the species phylogeny would correspond to geographic breaks (i.e., the Palghat gap) in the WG, and (3) species from each of the biogeographic subdivisions within the WG would form distinct clades. These hypotheses were tested on the centipede genus Digitipes from the WG which is known to be an ancient, endemic, and monophyletic group. The Digitipes molecular phylogeny was subjected to divergence date estimation using Bayesian approach, and ancestral areas were reconstructed using parsimony approach for each node in the phylogeny. Ancestral-area reconstruction suggested 13 independent dispersal events to explain the current distribution of the Digitipes species in the WG. Among these 13 dispersals, two dispersal events were at higher level in the Digitipes phylogeny and were from the southern WG to the central and northern WG independently in the Early Paleocene, after the Cretaceous Volcanism. The remaining 11 dispersal events explained the species' range expansions of which nine dispersals were from the southern WG to other biogeographic subdivisions in the Eocene-Miocene in the post-volcanic periods where species-level diversifications occurred. Taken together, these results suggest that southern WG might have served as a refuge for Digitipes species during Cretaceous volcanism.