Multiple Independent Recruitment of Sodefrin Precursor-Like Factors in Anuran Sexually Dimorphic Glands.

Chemical signaling in animals often plays a central role in eliciting a variety of responses during reproductive interactions between males and females. One of the best-known vertebrate courtship pheromone systems is sodefrin precursor-like factors (SPFs), a family of two-domain three-finger proteins with a female-receptivity enhancing function, currently only known from salamanders. The oldest divergence between active components in a single salamander species dates back to the Late Paleozoic, indicating that these proteins potentially gained a pheromone function earlier in amphibian evolution. Here, we combined whole transcriptome sequencing, proteomics, histology, and molecular phylogenetics in a comparative approach to investigate SPF occurrence in male breeding glands across the evolutionary tree of anurans (frogs and toads). Our study shows that multiple families of both terrestrially and aquatically reproducing frogs have substantially increased expression levels of SPFs in male breeding glands. This suggests that multiple anuran lineages make use of SPFs to complement acoustic and visual sexual signaling during courtship. Comparative analyses show that anurans independently recruited these proteins each time the gland location on the male's body allowed efficient transmission of the secretion to the female's nares.

Evolutionary History of the Asian Horned Frogs (Megophryinae): Integrative Approaches to Timetree Dating in the Absence of a Fossil Record.

Molecular dating studies typically need fossils to calibrate the analyses. Unfortunately, the fossil record is extremely poor or presently nonexistent for many species groups, rendering such dating analysis difficult. One such group is the Asian horned frogs (Megophryinae). Sampling all generic nomina, we combined a novel ∼5 kb dataset composed of four nuclear and three mitochondrial gene fragments to produce a robust phylogeny, with an extensive external morphological study to produce a working taxonomy for the group. Expanding the molecular dataset to include out-groups of fossil-represented ancestral anuran families, we compared the priorless RelTime dating method with the widely used prior-based Bayesian timetree method, MCMCtree, utilizing a novel combination of fossil priors for anuran phylogenetic dating. The phylogeny was then subjected to ancestral phylogeographic analyses, and dating estimates were compared with likely biogeographic vicariant events. Phylogenetic analyses demonstrated that previously proposed systematic hypotheses were incorrect due to the paraphyly of genera. Molecular phylogenetic, morphological, and timetree results support the recognition of Megophryinae as a single genus, Megophrys, with a subgenus level classification. Timetree results using RelTime better corresponded with the known fossil record for the out-group anuran tree. For the priorless in-group, it also outperformed MCMCtree when node date estimates were compared with likely influential historical biogeographic events, providing novel insights into the evolutionary history of this pan-Asian anuran group. Given a relatively small molecular dataset, and limited prior knowledge, this study demonstrates that the computationally rapid RelTime dating tool may outperform more popular and complex prior reliant timetree methodologies.

The impact of anchored phylogenomics and taxon sampling on phylogenetic inference in narrow-mouthed frogs (Anura, Microhylidae).

Despite considerable progress in unravelling the phylogenetic relationships of microhylid frogs, relationships among subfamilies remain largely unstable and many genera are not demonstrably monophyletic. Here, we used five alternative combinations of DNA sequence data (ranging from seven loci for 48 taxa to up to 73 loci for as many as 142 taxa) generated using the anchored phylogenomics sequencing method (66 loci, derived from conserved genome regions, for 48 taxa) and Sanger sequencing (seven loci for up to 142 taxa) to tackle this problem. We assess the effects of character sampling, taxon sampling, analytical methods and assumptions in phylogenetic inference of microhylid frogs. The phylogeny of microhylids shows high susceptibility to different analytical methods and datasets used for the analyses. Clades inferred from maximum-likelihood are generally more stable across datasets than those inferred from parsimony. Parsimony trees inferred within a tree-alignment framework are generally better resolved and better supported than those inferred within a similarity-alignment framework, even under the same cost matrix (equally weighted) and same treatment of gaps (as a fifth nucleotide state). We discuss potential causes for these differences in resolution and clade stability among discovery operations. We also highlight the problem that commonly used algorithms for model-based analyses do not explicitly model insertion and deletion events (i.e. gaps are treated as missing data). Our results corroborate the monophyly of Microhylidae and most currently recognized subfamilies but fail to provide support for relationships among subfamilies. Several taxonomic updates are provided, including naming of two new subfamilies, both monotypic.

Three new species of horned frogs, Megophrys (Amphibia: Megophryidae), from northeast India, with a resolution to the identity of Megophrys boettgeri populations reported from the region.

Northeast India is a well-established region of biological importance but remains poorly understood with regards to the species level identifications of many of its extant amphibians. In this study we examined small sized frogs from the genus Megophrys recently collected from remote and suburban forests in the northeast Indian states of Meghalaya and Arunachal Pradesh, from which we have identified three new species. Megophrys vegrandis sp. nov., Megophrys ancrae sp. nov. and Megophrys oropedion sp. nov. are compared with all known congeners from India and surrounding regions from which they differ based primarily on a combination of morphological characters. Megophrys boettgeri is removed, and Megophrys minor added to the Indian amphibian checklist, through critical review of all literature pertaining to the former species, and the discovery of an overlooked historical report of the latter species. Two of the new species, Megophrys ancrae sp. nov. and Megophrys vegrandis sp. nov. are known from low and mid elevations within two large protected forests in Arunachal Pradesh, both with poorly studied amphibian fauna. Contrastingly, Megophrys oropedion sp. nov. is currently known only from small forested areas on the upper reaches of the Shillong Plateau. The importance of the Shillong Plateau as an area of known high amphibian endemicity is highlighted in the light of the miniscule proportion of its land area afforded government protection, raising concerns about the future conservation of its still poorly known species.

Systematics of the caecilian family Chikilidae (Amphibia: Gymnophiona) with the description of three new species of Chikila from northeast India.

A taxonomic review of the monogeneric northeast Indian caecilian family Chikilidae is presented based on 64 specimens. Chikila fuilleri (Alcock, 1904), known previously only from a single specimen collected more than 100 years ago, is rediagnosed and characterised based on recent collections. We describe three additional species new to science, Chikila alcocki sp. nov., Chikila darlong sp. nov., and Chikila gaiduwani sp. nov. This species-level taxonomy is consistent with mitochondrial DNA sequence data. A key to the species of Chikila is presented.

Taxonomic review of the tree frog genus Rhacophorus from the Western Ghats, India (Anura: Rhacophoridae), with description of ontogenetic colour changes and reproductive behavior.

A taxonomic revision of the Western Ghats species from the genus Rhacophorus is presented. Based on museum studies and new collections from localities spanning the known range of Western Ghats Rhacophorus, we review the four known species of this genus, their type specimens, current taxonomic status and their geographic distribution on the basis of morphological and molecular data. The holotypes of Rhacophorus calcadensis, R. lateralis and R. nialabaricus are redescribed. The previously unidentified holotype of Rhacophorus inalabaricus is herein fixed. Descriptions of ontogenetic colour change (OCC) in the Western Ghats Rhacophorus are provided and we conjecture the taxonomic utility of OCC. Additionally we provide observations on nesting behaviour of each species, and report multiple male participation during amplexus, oviposition and foam nest construction in R. lateralis and R. malabaricus.

Larval morphology and natural history in two Minervarya species from Andaman Islands, with comments on a new phytotelmonous larval morphotype for the genus.

We studied the larval morphology and natural history of two species of Minervarya from the Andaman Islands of India. A recent assignment of Charles Darwins frog to the genus Minervarya opened up new questions on the systematic affinities and natural history of its enigmatic tadpoles. Originally described as Rana charlesdarwini Das, 1998, and long considered as Ingerana charlesdarwini, the tadpoles of this species were poorly understood and incomparable to those of other presumed close relatives based on an original brief description of its phytotelmonous tadpoles. Here we present a detailed redescription of the larval morphology of M. charlesdarwini based on genetically confirmed tadpoles. At the same time, we compared the external morphology of M. charlesdarwini tadpoles to that of its closest phylogenetic and sympatric congener, M. andamanensis, consequently reporting the first-ever larval description for M. andamanensis. For the first time also for minervaryan frogs, we record that M. charlesdarwini lays eggs on the inner walls of tree holes, and the tadpoles possess morphological adaptations for a phytotelmonous life. Their unique features, such as tail-to-body ratio >2.2, reduced labial tooth rows (LTRF 1/1), acutely pointed serrations in the jaw sheath, and the medial portion of the upper sheath broadly arched and that of the lower sheath U-shaped, justify adding a new larval morphotype to the genus Minervarya. In contrast, M. andamanensis breeds and undergoes development in ground water puddles and ponds, a common trait for other known minervaryan species. Furthermore, our study generates new knowledge on the amplexus, oviposition site, and early embryonic development in these species. The deeper understanding of the biology and habitat requirements contributes additional traits for future systematic and evolutionary studies, and helps guide conservation assessments for these two species endemic to a handful of islands in the Andaman Archipelago.

Discovery of a new family of amphibians from northeast India with ancient links to Africa.

The limbless, primarily soil-dwelling and tropical caecilian amphibians (Gymnophiona) comprise the least known order of tetrapods. On the basis of unprecedented extensive fieldwork, we report the discovery of a previously overlooked, ancient lineage and radiation of caecilians from threatened habitats in the underexplored states of northeast India. Molecular phylogenetic analyses of mitogenomic and nuclear DNA sequences, and comparative cranial anatomy indicate an unexpected sister-group relationship with the exclusively African family Herpelidae. Relaxed molecular clock analyses indicate that these lineages diverged in the Early Cretaceous, about 140 Ma. The discovery adds a major branch to the amphibian tree of life and sheds light on both the evolution and biogeography of caecilians and the biotic history of northeast India-an area generally interpreted as a gateway between biodiversity hotspots rather than a distinct biogeographic unit with its own ancient endemics. Because of its distinctive morphology, inferred age and phylogenetic relationships, we recognize the newly discovered caecilian radiation as a new family of modern amphibians.

Mountain-associated clade endemism in an ancient frog family (Nyctibatrachidae) on the Indian subcontinent.

Night frogs (Nyctibatrachidae) form a family endemic to the Western Ghats, a hill chain along the west coast of southern India. Extant members of this family are descendants of a lineage that originated on the subcontinent during its longtime isolation in the Late Cretaceous. Because the evolutionary history of Nyctibatrachidae has always been tightly connected to the subcontinent, these tropically-adapted frogs are an ideal group for studying how patterns of endemism originated and evolved during the Cenozoic in the Western Ghats. We used a combined set of mitochondrial and nuclear DNA fragments to investigate the phylogenetic relationships of 120 ingroup specimens of all known species of Nyctibatrachidae. Our analyses indicate that, although this family had an early origin on the Indian subcontinent, the early diversification of extant nyctibatrachids happened only in the Eocene. Biogeographic analyses show that dispersal across the Palghat gap and Shencottah gap was limited, which led to clade endemism within mountain ranges of the Western Ghats. It is likely that multiple biota have been affected simultaneously by these prominent geographical barriers. Our study therefore further highlights the importance of considering the Western Ghats-Sri Lanka biodiversity hotspot as an assemblage of distinct mountain regions, each containing endemism and deserving attention in future conservation planning.

Hiding in Plain Sight: Rain Water Puddles in Nicobar Islands of India Reveal Abundance of a New Frog Species of the Genus Microhyla Tschudi, 1838 (Anura: Microhylidae).

Recent studies on frogs of the Microhyla heymonsi species complex have demonstrated that high genetic variation exists among its various known populations from regions across Asia. We assessed the taxonomic identity of the Nicobar population of Microhyla cf. heymonsi and compared it to the typical Microhyla heymonsi from Taiwan and the two recently described species in this complex from Vietnam. Our study demonstrates that the Nicobar population is both genetically and morphologically divergent and warrants recognition as a new species, which we formally describe here as Microhyla nakkavaram sp. nov. The new species is closely related to M. daklakensis, M. heymonsi, and M. ninhthuanensis, but diagnosable from all three species by a suite of morphological characters, such as the presence of two small tubercles at mid-dorsum along with ( )-shaped markings, length of finger I longer than half the length of finger II, presence of three distinct metacarpal tubercles on hand, rudimentary foot webbing, as well as its slender body shape, granular dorsal skin texture, and other colour characters and body markings. Statistical analyses based on multiple morphometric characters also clearly separate our new taxon from M. heymonsi, with which it was previously confused. Our phylogenetic analyses based on the mitochondrial 16S rRNA locus find Microhyla nakkavaram sp. nov. to be nested in the Microhyla achatina species group, where it is delimited as a distinct species. This lineage shows genetic distances of ≥ 3.5% from all the other known congeners. Currently, the known distribution of the new taxon is restricted to the southernmost group of Nicobar Islands-Great Nicobar, Kondul, and Little Nicobar-where it is found in abundance across a wide range of habitats during the monsoon season. Our study underlines the need to reassess the identity of all the known populations of M. 'heymonsi' from other regions in Southeast and East Asia. To facilitate future taxonomic work in the light of our and other recent findings, we also provide a detailed redescription and revised diagnosis for M. heymonsi based on morphological examination of its century-old type material originating from Taiwan.

Molecular systematics of caeciliid caecilians (Amphibia: Gymnophiona) of the Western Ghats, India.

Together, Indian plus Seychelles caeciliid caecilian amphibians (Gymnophiona) constitute approximately 10% of the extant species of this order. A molecular phylogenetic analysis of all but one (or two) nominal species (16, in five genera) is presented based on mitochondrial (12S, 16S, cytb, cox1) and nuclear (RAG1) sequence data. Results strongly support monophyly of both Seychelles and peninsular Indian caeciliids, and their sister-group status. Within the Indian caeciliids, Indotyphlus and Gegeneophis are monophyletic sister genera. The phylogenetic position of Gegeneophis ramaswamii, Gegeneophis seshachari, and Gegeneophis carnosus are not well resolved, but all lie outside a well-supported clade of most northern Western Ghats Gegeneophis (madhavai, mhadeiensis, goaensis, danieli/nadkarnii). Most nominal species of Indian caeciliid are diagnosed by robust haplotype clades, though the systematics of G. carnosus-like forms in northern Kerala and southern Karnataka requires substantial further investigation. For the most part, Indian caeciliid species comprise narrowly distributed, allopatric taxa with low genetic diversity. Much greater geographic genetic diversity exists among populations referred to G. seshachari, such that some populations likely represent undescribed species. This, the first phylogenetic analysis of Indian caeciliids, generally provides additional support for recent increases in described species (eight since 1999), and a framework for ongoing taxonomic revision.

An integrative approach to infer systematic relationships and define species groups in the shrub frog genus Raorchestes, with description of five new species from the Western Ghats, India.

The genus Raorchestes is a large radiation of Old World tree frogs for which the Western Ghats in Peninsular India is the major center for origin and diversification. Extensive studies on this group during the past two decades have resolved long-standing taxonomic confusions and uncovered several new species, resulting in a four-fold increase in the number of known Raorchestes frogs from this region. Our ongoing research has revealed another five new species in the genus, formally described as Raorchestes drutaahu sp. nov., Raorchestes kakkayamensis sp. nov., Raorchestes keirasabinae sp. nov., Raorchestes sanjappai sp. nov., and Raorchestes vellikkannan sp. nov., all from the State of Kerala in southern Western Ghats. Based on new collections, we also provide insights on the taxonomic identity of three previously known taxa. Furthermore, since attempts for an up-to-date comprehensive study of this taxonomically challenging genus using multiple integrative taxonomic approaches have been lacking, here we review the systematic affinities of all known Raorchestes species and define 16 species groups based on evidence from multi-gene (2,327 bp) phylogenetic analyses, several morphological characters (including eye colouration and pattern), and acoustic parameters (temporal and spectral properties, as well as calling height). The results of our study present novel insights to facilitate a better working taxonomy for this rather speciose and morphologically conserved radiation of shrub frogs. This will further enable proper field identification, provide momentum for multi-disciplinary studies, as well as assist conservation of one of the most colourful and acoustically diverse frog groups of the Western Ghats biodiversity hotspot.

A tiny new species of Microhyla Tschudi, 1838 (Amphibia: Anura: Microhylidae) from Belitung Island and Southeastern Sumatra, Indonesia.

A tiny new species of narrow-mouthed frog of the genus Microhyla is described from the island of Belitung and southeastern Sumatra, Indonesia. The most distinctive feature of the new frog is its diminutive adult size, snout-vent length ranging only from 12.3 to 15.8 mm in adult males. Phylogenetic analyses based a fragment of the mitochondrial 16S rRNA gene, along with detailed morphological and acoustic comparison differentiate the new taxon from all known congeners. The new species, formally described as Microhyla sriwijaya sp. nov., is a member of the M. achatina species group and the sister taxon to M. orientalis. It is diagnosable from other congeners by a combination of characters: (1) smaller male snout-vent size 16 mm; (2) snout obtusely rounded in dorsal view; (3) absence of mid-dorsal line and skin fold; (4) first finger reduced (finger I length less than half of finger II length); (5) dorsum with a prominent dark median mark extending posteriorly, narrow anteriorly near the level of the shoulder and expanding dorsolaterally up to the vent; margins of the dorsal marking concave with broad reddish-brown or orange colouration on either side; (6) foot webbing rudimentary, reaching just up to the first subarticular tubercle on all toes; (7) dorsal skin with prominent tubercles, especially in life; (8) tibiotarsal articulation of adpressed limb reaching beyond the snout tip; and (9) males produce a single type of call with pulsatile temporal structure, calls of relatively short duration ranging between 31.862.8 s, with two to three pulses delivered at a rate ranging between 32.236.0 pulses per second, and the mean overall dominant frequency of 4.3 kHz. The uncorrected pairwise genetic distances between Microhyla sriwijaya sp. nov. and all other known congeners are > 3.8% for the studied 16S gene fragment. The new species was discovered from wayside rural areas with oil palm plantations at four localities in the small island of Belitung (type locality), and from coffee plantation and secondary forest at Lampung in southeastern Sumatra. It is not known from any protected area and appears to be threatened due to tin mining activity, intensive logging, oil palm, and other commonly practiced agriculture activities.

New frog family from India reveals an ancient biogeographical link with the Seychelles.

About 96% of the more than 4,800 living anuran species belong to the Neobatrachia or advanced frogs. Because of the extremely poor representation of these animals in the Mesozoic fossil record, hypotheses on their early evolution have to rely largely on extant taxa. Here we report the discovery of a burrowing frog from India that is noticeably distinct from known taxa in all anuran families. Phylogenetic analyses of 2.8 kilobases of mitochondrial and nuclear DNA unambiguously designate this frog as the sister taxon of Sooglossidae, a family exclusively occurring on two granitic islands of the Seychelles archipelago. Furthermore, molecular clock analyses uncover the branch leading to both taxa as an ancient split in the crown-group Neobatrachia. Our discovery discloses a lineage that may have been more diverse on Indo-Madagascar in the Cretaceous period, but now only comprises four species on the Seychelles and a sole survivor in India. Because of its very distinct morphology and an inferred origin that is earlier than several neobatrachian families, we recognize this frog as a new family.

New insights on the systematics and reproductive behaviour in tree frogs of the genus Feihyla, with description of a new related genus from Asia (Anura, Rhacophoridae).

The taxonomy of the Asian tree frog genus Feihyla has been in a state of flux ever since its proposal in 2006. Allocation of species to Feihyla remains confusing, particularly with respect to the closely related genus Chirixalus (formerly Chiromantis sensu lato). At the same time, several Chirixalus species are known only from cursory descriptions and remain poorly studied. In this study, we review the systematics of the genus Feihyla and clarify the generic placement of its members along with all other species currently assigned to Chirixalus. Based on integrative evidence gathered from new collections, examination of types and original descriptions, morphological comparisons, phylogenetic relationships inferred from a multi-gene (three mitochondrial + two nuclear) 1,937 bp dataset, as well as reproductive modes including egg-laying, nesting behaviour, and clutch morphology, our results show that the six species formerly attributed to Feihyla represent three morphologically and phylogenetically distinct groups: (1) the type species of the genus, F. palpebralis, along with F. fuhua constitute the Feihyla palpebralis group or Feihyla sensu stricto; (2) F. inexpectata and F. kajau represent the Feihyla vittiger group and are closely related to the Feihyla palpebralis group; (3) 'F. hansenae' and 'F. vittata' constitute another distinct and reciprocally monophyletic lineage, more closely related to Chirixalus + Chiromantis. In light of long-standing taxonomic confusions and unresolved phylogenetic relationships, we propose recognition of a new genus to accommodate 'F. hansenae' and 'F. vittata' in order to stabilise the classification of several Asian rhacophorid species that have been frequently confused and transferred within the Chirixalus-Chiromantis-Feihyla complex. Based on integrative evidence, eight species previously attributed to the genus Chirixalus or Feihyla are formally transferred to Rohanixalus gen. nov., two Chirixalus members are allocated to Feihyla, and one synonymised with Rhacophorus bipunctatus. In addition, we report the first member of the tree frog family Rhacophoridae from the Andaman Islands of India-Rohanixalus vittatus, along with description of its male advertisement call, reproductive behaviour including parental care by the female, and larval morphology. Extended distributions are also provided for Rohanixalus species across Northeast India. The study further reveals the presence of potentially undescribed diversity in the new genus. Altogether, the revised classification and novel insights presented herein will facilitate a better working taxonomy for four phylogenetically distinct but morphologically related groups of Old World tree frogs.

Toad radiation reveals into-India dispersal as a source of endemism in the Western Ghats-Sri Lanka biodiversity hotspot.

BACKGROUND: High taxonomic level endemism in the Western Ghats-Sri Lanka biodiversity hotspot has been typically attributed to the subcontinent's geological history of long-term isolation. Subsequent out of -- and into India dispersal of species after accretion to the Eurasian mainland is therefore often seen as a biogeographic factor that 'diluted' the composition of previously isolated Indian biota. However, few molecular studies have focussed on into-India dispersal as a possible source of endemism on the subcontinent. Using c. 6000 base pairs of mitochondrial and nuclear DNA, we investigated the evolutionary history and biogeography of true toads (Bufonidae), a group that colonized the Indian Subcontinent after the Indo-Asia collision. RESULTS: Contrary to previous studies, Old World toads were recovered as a nested clade within New World Bufonidae, indicating a single colonization event. Species currently classified as Ansonia and Pedostibes were both recovered as being non-monophyletic, providing evidence for the independent origin of torrential and arboreal ecomorphs on the Indian subcontinent and in South-East Asia. Our analyses also revealed a previously unrecognized adaptive radiation of toads containing a variety of larval and adult ecomorphs. Molecular dating estimates and biogeographic analyses indicate that the early diversification of this clade happened in the Western Ghats and Sri Lanka during the Late Oligocene to Early Miocene. CONCLUSION: Paleoclimate reconstructions have shown that the Early Neogene of India was marked by major environmental changes, with the transition from a zonal- to the current monsoon-dominated climate. After arrival in the Western Ghats-Sri Lanka hotspot, toads diversified in situ, with only one lineage able to successfully disperse out of these mountains. Consequently, higher taxonomic level endemism on the Indian Subcontinent is not only the result of Cretaceous isolation, but also of invasion, isolation and radiation of new elements after accretion to the Eurasian mainland.

Author Correction: New microhylid frog genus from Peninsular India with Southeast Asian affinity suggests multiple Cenozoic biotic exchanges between India and Eurasia.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

New microhylid frog genus from Peninsular India with Southeast Asian affinity suggests multiple Cenozoic biotic exchanges between India and Eurasia.

Anurans in Peninsular India exhibit close biogeographical links with Gondwana as well as Laurasia, often explainable by the geological history of the Indian subcontinent; its breakup from Gondwanan landmasses followed by long isolation that resulted in diversification of endemic lineages, and subsequent land connections with Asia that enabled dispersal of widespread groups. Although widely distributed, the frog subfamily Microhylinae mostly comprises of geographically restricted genera found either in Southeast and East Asia or Peninsular India and Sri Lanka. Here we report a previously unknown microhylid from the Western Ghats in Peninsular India with closest relatives found over 2,000 km away in Southeast Asia. Based on integrated evidence from mitochondrial and nuclear DNA, adult and tadpole morphology, hand musculature, male advertisement call, and geographical distance, we recognize this enigmatic frog as a distinct new species and genus endemic to the Western Ghats. The discovery of Mysticellus franki gen. et sp. nov. and its close evolutionary relationship with the Southeast Asian genus Micryletta also provide insights on the biogeography of Microhylinae. Genus-level divergences within the subfamily suggest multiple Cenozoic biotic exchange events between India and Eurasia, particularly through postulated Eocene land bridges via Southeast Asia prior to accretion of the two landmasses.

A new Microhyla species (Anura: Microhylidae) from riparian evergreen forest in the eastern Himalayan state of Arunachal Pradesh, India.

A new frog species of the genus Microhyla (Anura, Microhylidae) is described from riparian mid-elevation (860 m asl) evergreen forest in Namdapha National Park, located in the eastern Himalayan state of Arunachal Pradesh, India. The new species can be morphologically distinguished from other congeners by a suite of characters such as adult size, dorsal and lateral colouration and markings, snout shape, foot webbing, and digit tip morphology. Phylogenetically, the new species is more closely related to some of the smallest known members of the genus. It forms a deeply divergent sister lineage to the clade containing members of the Microhyla zeylanica species group that are restricted to Peninsular India and Sri Lanka, and shows sequential relationship with Southeast Asian species M. superciliaris, followed by clade containing M. aurantiventris + M. butleri. The discovery indicates that novel taxa representing distinct evolutionary lineages still remain to be formally described in the genus Microhyla, especially from less explored regions such as the eastern Himalayan forests in Northeast India.

A new species of Micryletta frog (Microhylidae) from Northeast India.

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.