[Ichthyology • 2025] Sinocyclocheilus wanlanensis • Description of A New Eyeless Cavefish (Cypriniformes: Cyprinidae) Using Integrative Taxonomic Methods, from Guizhou, China

 

 Sinocyclocheilus wanlanensis  Liu, Mao & Yang,

in Liu, Mao, Sudasinghe, Chen, Yang et Meegaskumbura, 2025

  DOI: doi.org/10.3390/ani15152216 

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Simple Summary

The karst caves of southwest China are home to an extraordinary diversity of cavefish, especially those in the Sinocyclocheilus group, the largest cavefish genus in the world. Using a combination of morphology and genetic analyses, we describe a new species, Sinocyclocheilus wanlanensis, found in an underground river in Guizhou Province. This fish is eyeless or degenerate-eyed, has no horn-like structures on its head (unlike some of its relatives), and features a large hump behind the head and a snout shaped like a duck’s bill. Measurement and comparison with similar species show that it is distinct morphologically. DNA analysis of two mitochondrial genes places it close to S. bicornutus, a related species; the genetic differences, while small, are consistent with what we observe between known sister species. Sinocyclocheilus wanlanensis is also distinct in appearance: it has degenerated eyes (dark spot) or no eyes (compared to the normal eyes of S. bicornutus); it also lacks the split horn found in S. bicornutus. It can be distinguished from the similar-looking S. zhenfengensis by its eyeless/degenerate-eye condition, shorter facial barbels, and longer pelvic fins. Identifying and describing new species is important for protecting cave life and understanding how species evolve in extreme environments.

Abstract

China’s southwestern karst landscapes support remarkable cavefish diversity, especially within Sinocyclocheilus, the world’s largest cavefish genus. Using integrative taxonomic methods, we describe Sinocyclocheilus wanlanensis sp. nov., found in a subterranean river in Guizhou Province. This species lacks horn-like cranial structures; its eyes are either reduced to a dark spot or absent. It possesses a pronounced nuchal hump and a forward-protruding, duckbill-shaped head. Morphometric analysis of 28 individuals from six species shows clear separation from related taxa. Nano-CT imaging reveals distinct vertebral and cranial features. Phylogenetic analyses of mitochondrial cytb and ND4 genes place S. wanlanensis within the S. angularis group as sister to S. bicornutus, with p-distances of 1.7% (cytb) and 0.7% (ND4), consistent with sister-species patterns within the genus. Sinocyclocheilus wanlanensis is differentiated from S. bicornutus by its eyeless or degenerate-eye condition and lack of bifurcated horns. It differs from S. zhenfengensis, its morphologically closest species, in having degenerate or absent eyes, shorter maxillary barbels, and pelvic fins that reach the anus. The combination of morphological and molecular evidence supports its recognition as a distinct species. Accurate documentation of such endemic and narrowly distributed taxa is important for conservation and for understanding speciation in cave habitats.

Keywords: Sinocyclocheilus; new species; Beipanjiang River; cytochrome b; NADH dehydrogenase subunit 4; integrative taxonomy; cavefish; molecular systematics; mtDNA; China

 Sinocyclocheilus wanlanensis sp. nov., GXU2020000062, holotype, 86.74 mm SL.
(A) Live specimen (not holotype); (B) lateral view of head in preserved specimen; (C) dorsal view of preserved specimen.

Sinocyclocheilus wanlanensis Liu, Mao & Yang, sp. nov.

Diagnosis. Sinocyclocheilus wanlanensis is distinguished from all its congeners by the following combination of characters: absence of horn-like structure; eyes absent or degenerated into dark spots; a distinct nuchal hump; predorsal profile distinctly arched; the tip of the adpressed rostral barbel extending posteriorly not reaching vertical through the anterior margin of the sunken eye or dark spot; tip of the pelvic-fin rays reaching the anus when pelvic-fin rays extended backward; a distinct head shape protruding forward, resembling a duck’s beak; body scaleless; in life, body light golden brown; lateral line pores 41–45; gill rakers well developed, 9 on first gill arch.

Distribution and habitat. Known only from a subterranean river within a cave in the town of Wanlan, Zhenfeng County, Guizhou Province, China. This underground river serves as an important source of drinking and irrigation water for local villagers. They have established large and small pumps to extract water from the cave. The water from this underground river eventually flows into the Beipanjiang River. Sinycyclocheilus wanlanensis occurs in sympatry with several other fish species: Longanalus macrochirous, Pterocryptis anomala, Carassius auratus, and Opsariicthys bidens.

Etymology. The new species’ name, wanlanensis, derives from Wanlan Town, Zhenfeng County, where the type specimens were collected.

  

Yewei Liu, Tingru Mao, Hiranya Sudasinghe, Rongjiao Chen, Jian Yang and Madhava Meegaskumbura. 2025. Description of A New Eyeless Cavefish Using Integrative Taxonomic Methods—Sinocyclocheilus wanlanensis (Cypriniformes, Cyprinidae), from Guizhou, China. Animals. 15(15), 2216. DOI: doi.org/10.3390/ani15152216 [28 July 2025] 

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[Ichthyology • 2018] Rasboroides vaterifloris & P. pallidus • Undocumented Translocations Spawn Taxonomic Inflation in Sri Lankan Fire Rasboras (Actinopterygii, Cyprinidae)

(A–D) Rasboroides vaterifloris Deraniyagala, 1930
(E–J) Rasboroides pallidus Deraniyagala, 1958

in Sudasinghe, Herath, Pethiyagoda & Meegaskumbura, 2018. 

DOI: 10.7717/peerj.6084

Abstract

A recent (2013) taxonomic review of the freshwater-fish genus Rasboroides, which is endemic to Sri Lanka, showed it to comprise four species: R. vaterifloris, R. nigromarginatus, R. pallidus and R. rohani. Here, using an integrative-taxonomic analysis of morphometry, meristics and mitochondrial DNA sequences of cytochrome b (cytb) and cytochrome oxidase subunit 1 (coi), we show that R. nigromarginatus is a synonym of R. vaterifloris, and that R. rohani is a synonym of R. pallidus. The creation and recognition of unnecessary taxa (‘taxonomic inflation’) was in this case a result of selective sampling confounded by a disregard of allometry. The population referred to R. rohani in the Walawe river basin represents an undocumented trans-basin translocation of R. pallidus, and a translocation into the Mahaweli river of R. vaterifloris, documented to have occurred ca 1980, in fact involves R. pallidus. A shared haplotype suggests the latter introduction was likely made from the Bentara river basin and not from the Kelani, as claimed. To stabilize the taxonomy of these fishes, the two valid species, R. vaterifloris and R. pallidus, are diagnosed and redescribed, and their distributions delineated. We draw attention to the wasteful diversion of conservation resources to populations resulting from undocumented translocations and to taxa resulting from taxonomic inflation. We argue against translocations except where mandated by a conservation emergency, and even then, only when supported by accurate documentation.

Figure 4: Live color pattern variation in A–D, Rasboroides vaterifloris; E–J, R. pallidus.
(A) topotypes of R. vaterifloris, Kalu basin, Gilimale; (B–D) topotypes of population identified as R. nigromarginatus by Batuwita, De Silva & Edirisinghe (2013), Kalu basin, Athwelthota; (E) Bentara basin, Pitigala; (F) topotypes of population identified as R. rohani by Batuwita, De Silva & Edirisinghe (2013), Walawe basin, Suriyakanda; (G) Bentara basin, Yagirala; (H) Gin basin, Udugama; (I) Bentara basin, Yagirala; (J) Bentara basin, Pitigala. (A, B, D, E, F, G, H) males; (C, I, J) females. Specimens not collected.

 Live color pattern variation in Rasboroides vaterifloris.
(A) topotypes of R. vaterifloris, Kalu basin, Gilimale; (B–D) topotypes of population identified as R. nigromarginatus by Batuwita, De Silva & Edirisinghe (2013), Kalu basin, Athwelthota.

 (A, B, D) males; (C) females. Specimens not collected.

Rasboroides vaterifloris Deraniyagala, 1930

Rasbora vaterifloris Deraniyagala, 1930: 129

Rasbora nigromarginata Meinken, 1957: 65–68

Rasbora vaterifloris var. nigromarginatus Deraniyagala, 1958: 137

Rasboroides nigromarginatus (Meinken, 1957): Batuwita, De Silva & Edirisinghe, 2013

Diagnosis. Males of Rasboroides vaterifloris can be distinguished from males of R. pallidus by having the unbranched rays of dorsal, anal, pectoral and pelvic fins black along their entire length, more distinctly evident in the last unbranched ray of the dorsal fin (vs. the mentioned rays being the same color as other rays; in preserved specimens, interradial membranes of dorsal, anal, pelvic and pectoral fins with distinct, scattered melanophores (vs. absent or vaguely present only around the beginning). Females of R. vaterifloris have a lesser body depth (27.2–31.9% SL vs. 31.7–35.5) than those of R. pallidus.

Live color pattern variation in Rasboroides  pallidus. (E) Bentara basin, Pitigala; (F) topotypes of population identified as R. rohani by Batuwita, De Silva & Edirisinghe (2013), Walawe basin, Suriyakanda; (G) Bentara basin, Yagirala; (H) Gin basin, Udugama; (I) Bentara basin, Yagirala; (J) Bentara basin, Pitigala.

 (E, F, G, H) males; (I, J) females. Specimens not collected.

Rasboroides pallidus Deraniyagala, 1958

Rasbora vaterifloris pallida Deraniyagala, 1958: 136.

Rasbora vaterifloris ruber Deraniyagala, 1958: 136.

Rasbora vaterifloris rubioculis Deraniyagala, 1958: 136.

Rasboroides rohani Batuwita, De Silva & Edirisinghe, 2013

Diagnosis. The males of Rasboroides pallidus can be distinguished from the males of R.  vaterifloris by having the unbranched rays of dorsal, anal, pectoral and pelvic fins the same color as other branched rays (vs. black along their entire length); in preserved specimens, interradial membranes of dorsal, anal, pelvic and pectoral fins without distinct scattered melanophores throughout or with only minute, vague melanophores only around the beginning (vs. melanophores distinctly present). The females of R. pallidus have greater body depth (31.7–35.5% SL vs. 27.2–31.9) than females of R. vaterifloris.

Conclusion: 

As a freshwater-fish genus endemic to Sri Lanka and restricted largely to streams draining the island’s dwindling rainforest estate, Rasboroides attracts considerable conservation attention. The National Red List (MOE, 2012) treats ‘R. nigromarginatus’ as Critically Endangered and R. vaterifloris as Endangered. The synonymy of these two nominal species demonstrated here allows their ranges to be combined, widening their extent of occurrence and area of occupancy and hence potentially lowering the threat-status of R. vaterifloris. Although ‘R. rohani’ has not as yet been assessed for conservation purposes, its restriction to a small population at a single locality would almost certainly have caused it to be ranked as Critically Endangered. Given that we show here that it represents only an undocumented translocation of R. pallidus, its population is now only of marginal conservation concern. Indeed, of the two valid species of Rasboroides, R. pallidus enjoys the wider range and hence warrants less conservation concern, especially given its successful translocation to two river basins (Mahaweli and Walawe) in which it did not previously occur.

In describing ‘R. rohani’ as a new species, Batuwita, De Silva & Edirisinghe (2013) were misled by apparently collecting only the largest specimens for their sample while neglecting to account for allometric growth. It is additionally regrettable that the type series of ‘R. rohani’ designated by these authors cannot be identified in the collection of the National Museum of Sri Lanka, in which it was stated to be deposited.

Both translocations referred to in this paper were made by well-meaning citizens but without the safeguards that should apply in such cases. Perhaps most egregiously, no records were published of the rationale for translocation or the precise identity and origin of the source population. We urge that any future attempts to introduce species to novel habitats be guided by IUCN/SSC (2013) and that the intentional release or introduction of species without legal sanction be prohibited in Sri Lanka.

Hiranya Sudasinghe, Jayampathi Herath, Rohan Pethiyagoda and Madhava Meegaskumbura. 2018. Undocumented Translocations Spawn Taxonomic Inflation in Sri Lankan Fire Rasboras (Actinopterygii, Cyprinidae). PeerJ. 6:e6084.  DOI: 10.7717/peerj.6084

[Herpetology • 2019] Diversification of Shrub Frogs (Rhacophoridae, Pseudophilautus) in Sri Lanka – Timing and Geographic Context

in Meegaskumbura, Senevirathne, Manamendra-Arachchi, et al., 2019. 

  DOI: 10.1016/j.ympev.2018.11.004 

Highlights

• Pseudophilautus diversification, begins during Oligocene (31 MYA)

• A stately pace of lineage accumulation despite orogeny and climate change.

• Assemblages in most regions comprise of species arising from diverse clades.

• MRCA of a back-migrating clade to India (8.8 MYA), reconstructs as a lowland form.

 • Island’s mountains serve as species pumps and refuges for Pseudophilautus evolution.

Abstract

Pseudophilautus comprises an endemic diversification predominantly associated with the wet tropical regions of Sri Lanka that provides an opportunity to examine the effects of geography and historical climate change on diversification. Using a time-calibrated multi-gene phylogeny, we analyze the tempo of diversification in the context of past climate and geography to identify historical drivers of current patterns of diversity and distribution. Molecular dating suggests that the diversification was seeded by migration across a land-bridge connection from India during a period of climatic cooling and drying, the Oi-1 glacial maximum around the Eocene-Oligocene boundary. Lineage-through-time plots suggest a gradual and constant rate of diversification, beginning in the Oligocene and extending through the late Miocene and early Pliocene with a slight burst in the Pleistocene. There is no indication of an early-burst phase of diversification characteristic of many adaptive radiations, nor were there bursts of diversification associated with favorable climate shifts such as the intensification of monsoons. However, a late Miocene (8.8 MYA) back-migration to India occurred following the establishment of the monsoon. The back migration, however, did not trigger a diversification in India similar to that manifest in Sri Lanka, likely due to occupation of available habitat, and consequent lack of ecological opportunity, by the earlier radiation of a sister lineage of frogs (Raorchestes) with similar ecology. Phylogenetic area reconstructions show a pattern of sister species distributed across adjacent mountain ranges or from different parts of large montane regions, highlighting the importance of isolation and allopatric speciation. Hence, local species communities are composed of species from disparate clades that, in most cases, have been assembled through migration rather than in situ speciation. Lowland lineages are derived from montane lineages. Thus, the hills of Sri Lanka acted as species pumps as well as refuges throughout the 31 million years of evolution, highlighting the importance of tropical montane regions for both the generation and maintenance of biodiversity.

Keywords: Ancestral-area reconstruction, Biogeography, Ecological opportunity, Diversification, Molecular dating, Speciation

 Madhava Meegaskumbura, Gayani Senevirathne, Kelum Manamendra-Arachchi, Rohan Pethiyagoda, James Hanken and Christopher J. Schneider. 2019. Diversification of Shrub Frogs (Rhacophoridae, Pseudophilautus) in Sri Lanka – Timing and Geographic context. Molecular Phylogenetics and Evolution. In Press. DOI: 10.1016/j.ympev.2018.11.004

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[Herpetology • 2015] Realities of Rarity: Climatically and Ecologically Restricted, Critically Endangered Kandian Torrent Toads (Adenomus kandianus) Breed en masse

Figure 1: Amplexus and mating aggregations in Adenomus kandianus.
(a) An amplexed pair out of water, showing axillary amplexus. (b–c) A large mating aggregation in slow water, sandy-bottomed refuge in a stream bordering the Peak Wilderness sanctuary. 

MeegaskumburaLab.blogspot.com  DOI: 10.7287/peerj.preprints.1575v1

Abstract

Endemic to Sri Lanka, genus Adenomus contains two torrent-associated toad species whose ecology and natural history in the wild is virtually unknown. Adenomus kelaartii is relatively common, with a wide geographic distribution. Its sister species, A. kandianus, however, is restricted to two isolated populations in fast-disappearing montane and sub-montane forests. Formally declared extinct after not being recorded for over a century, a few A. kandianus were rediscovered in 2012 and redescribed as "the world's rarest toad". Here we report the results of a two-year study of the occurrence, habits and habitat associations of adult and larval A. kandianus using both general surveys and quadrat sampling. We show this to be a secretive species with a patchy distribution. Non-breeding female toads dwell in primary-forest habitats, but after heavy and sudden downpours they form large mating congregations in large streams. Amplexed pairs swim synchronously, enabling them to traverse fast currents. Egg-laying sites remain unknown, but the ability to dive and vocalize underwater, and characteristics of the eggs, suggest that they lay eggs in dark recesses of the stream. Tadpoles show microhabitat partitioning within the stream, with the greatest diversity of stages in slow-flowing rocky areas. The more robust stages possessing sucker discs exploit rocky-rapids, while metamorphic stages inhabit stream margins. We use DNA-barcoding to show the existence of two disparate toad populations. Distribution modeling with forest-cover layers added, predict a very small remaining area of suitable habitats. Conservation of this climatically and ecologically restricted species hinge largely on the preservation of high-elevation primary and riparian forests and unpolluted torrents.

Figure 1: Amplexus and mating aggregations in Adenomus kandianus.
(a) An amplexed pair out of water, showing axillary amplexus. (b–d) A large mating aggregation in slow water, sandy-bottomed refuge in a stream bordering the Peak Wilderness sanctuary.

DOI: 10.7287/peerj.preprints.1575v1

  Madhava Meegaskumbura, Nayana Wijayathilaka, Nirodha Abayalath and Gayani Senevirathne. 2015.  Realities of Rarity: Climatically and Ecologically Restricted, Critically Endangered Kandian Torrent Toads (Adenomus kandianus) Breed en masse.
PeerJ PrePrints 3:e1964. DOI: 10.7287/peerj.preprints.1575v1

ResearchGate.net/publication/287260395_Realities_of_rarity_climatically_and_ecologically_restricted_critically_endangered_Kandian_Torrent_Toads_Adenomus_kandianus_breed_en_masse

meegaskumburalab.blogspot.com/2015/12/a-lost-torrent-toad-forms-large.html

[Ichthyology • 2016] Ompok argestes • A New Species of Silurid Catfish (Teleostei: Siluridae) Endemic to Sri Lanka

Ompok argestes 

 Sudasinghe & Meegaskumbura, 2016  
 DOI: 10.11646/zootaxa.4158.2.7 

Abstract

Ompok argestes, a new species of silurid catfish, is described from the southwestern lowlands of Sri Lanka. The new species is distinguished from all other species of Ompok in the Indian subcontinent by a combination of the following characters: body color pattern mottled; predorsal profile uniformly convex; maxillary barbels reach or extend slightly beyond base of dorsal fin; eye diameter 14.2–17.1% head length (HL); body depth at anus 19.8–22.3% standard length (SL); head width 14.3–16.8% SL; caudal peduncle depth 5.6–6.5% SL. Callichrous ceylonensis Günther is shown to be a valid species that is apparently restricted to Sri Lanka, distinguished by a combination of the following characters: distinct concavity in predorsal profile; origin of pelvic fin beneath or slightly posterior to the origin of the dorsal fin; maxillary barbels 108–166 % HL; mandibular barbels 16.1–33.7 % HL; and 58–66 anal-fin rays.

Keywords: Pisces, Ostariophysi, Ompok bimaculatus, Callichrous ceylonensis, India, Tranquebar

H. Sudasinghe and M. Meegaskumbura. 2016. Ompok argestes, A New Species of Silurid Catfish Endemic to Sri Lanka (Teleostei: Siluridae). Zootaxa. 4158(2); 261-271.  DOI: 10.11646/zootaxa.4158.2.7

ResearchGate.net/publication/307181329_Ompok_argestes_a_new_species_of_silurid_catfish_endemic_to_Sri_Lanka_Teleostei_Siluridae

 

[Herpetology • 2016] From Clinging to Digging: The Postembryonic Skeletal Ontogeny of the Indian Purple Frog, Nasikabatrachus sahyadrensis (Anura: Nasikabatrachidae)

Young metamorphs of the Indian Purple frog Nasikabatrachus sahyadrensis, ready to dig and follow their parents underground. 

DOI: 10.1371/journal.pone.0151114 

Abstract

The Indian Purple frog, Nasikabatrachus sahyadrensis, occupies a basal phylogenetic position among neobatrachian anurans and has a very unusual life history. Tadpoles have a large ventral oral sucker, which they use to cling to rocks in torrents, whereas metamorphs possess adaptations for life underground. The developmental changes that underlie these shifts in habits and habitats, and especially the internal remodeling of the cranial and postcranial skeleton, are unknown. Using a nearly complete metamorphic series from free-living larva to metamorph, we describe the postembryonic skeletal ontogeny of this ancient and unique monotypic lineage. The torrent-dwelling larva possesses a dorsoventrally flattened body and a head with tiny dorsal eyes, robust lower and upper jaw cartilages, well-developed trabecular horns, and a definable gap between the trabecular horns and the tip of the snout. Unlike tadpoles of many other frogs, those of Nasikabatrachus retain larval mouthparts into late metamorphic stages. This unusual feature enables the larvae to maintain their clinging habit until near the end of metamorphosis. The subsequent ontogenetic shift from clinging to digging is correlated with rapid morphological changes and behavioral modifications. Metamorphs are equipped with a shortened tibiafibula and ossified prehallical elements, which likely facilitate initial digging using the hind limbs. Subsequently, the frogs may shift to headfirst burrowing by using the wedge-shaped skull, anteriorly positioned pectoral girdle, well-developed humeral crests and spatula-shaped forelimbs. The transition from an aquatic life in torrents to a terrestrial life underground entails dramatic changes in skeletal morphology and function that represent an extreme in metamorphic remodeling. Our analysis enhances the scope for detailed comparative studies across anurans, a group renowned for the diversity of its life history strategies.

Rapid metamorphic remodeling associated with the development of Indian Purple frog Nasikabatrachus sahyadrensis tadpoles.

DOI: 10.1371/journal.pone.0151114

Gayani Senevirathne, Ashish Thomas, Ryan Kerney, James Hanken, S. D. Biju and Madhava Meegaskumbura. 2016. From Clinging to Digging: The Postembryonic Skeletal Ontogeny of the Indian Purple Frog, Nasikabatrachus sahyadrensis (Anura: Nasikabatrachidae).  PLoS ONE. DOI: 10.1371/journal.pone.0151114

Rapid transformation turns clinging tadpoles into digging adult frogs
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[Herpetology • 2016] Unearthing the Fossorial Tadpoles of the Indian Dancing Frog Family Micrixalidae, Micrixalus herrei

Fig 1. Habitat preference and characteristic features of various life history stages of Micrixalus herrei.
 (A) Adult male (SDBDU 2012.2452, SVL 17.40 mm), found on the surface of emergent wet rocks along the stream; (B) metamorphosed larva, near shallow water, closer to the stream bank (stage 44, SVL 17.20 mm); (C) stream margin habitat of metamorphs (stages 43–44); (D) anguilliform bodied tadpoles on the gravel bed (stages 30–35), after being exposed from depths of about 30 cm; (E) egg clutch (N = 20) buried under sand in shallow water; (F) fossorial tadpoles after being exposed, at stages 26 (1), 28 (2), and 29 (3), having eel-like, dorsoventrally flattened bodies, dorsal eyes, and well-developed muscular tails with reduced fins; (G) lateral profile of a tadpole, observed amongst exposed gravel (stage 27).

DOI: 10.1371/journal.pone.0151781

Abstract

Tadpoles of the monotypic Indian dancing frog family Micrixalidae have remained obscure for over 125 years. Here we report the discovery of the elusive tadpoles of Micrixalus herrei from the sand beds of a forested stream in southern Western Ghats, and confirm their identity through DNA barcoding. These actively burrowing tadpoles lead an entirely fossorial life from eggs to late metamorphic stages. We describe their internal and external morphological characters while highlighting the following features: eel-like appearance, extensively muscularized body and tail, reduced tail fins, skin-covered eyes, delayed development of eye pigmentation in early pre-metamorphic stages (Gosner stages 25–29), prominent tubular sinistral spiracle, large transverse processes on vertebrae II and III, ankylosed ribs on transverse processes of vertebra II, notochord terminating before the atlantal cotyle-occipital condyle junction, absence of keratodonts, serrated well-formed jaw sheaths, and extensive calcified endolymphatic sacs reaching sacrum posteriorly. The tadpole gut contains mostly fine sediments and sand. We discuss the eel-like morphology and feeding habits of M. herrei in the context of convergence with other well-known fossorial tadpoles. This discovery builds the knowledge base for further comparative analyses and conservation of Micrixalus, an ancient and endemic lineage of Indian frogs.

Discussion

This description of the external morphology, osteology and ecological adaptations, of Micrixalus herrei provides the first confirmed report of a tadpole from the ancient anuran family, Micrixalidae. The present study also bridges a significant gap by documenting the life history of at least one representative species from each of the world’s 54 anuran families, which facilitates comparative studies across many disciplines, including development, evolution, and ecology.

There is a single report of Micrixalus tadpoles by Smith[14] based on “two poorly preserved specimens said to belong to M. opisthorhodus” (currently M. phyllophilus). According to the basic description provided by Smith[14], these tadpoles bear a single row of keratodonts, which subsequently were considered “characteristic” of micrixalid tadpoles without further investigation[15–17]. This observation is contrary to our finding that M. herrei tadpoles, along with three other micrixalid species (currently being studied in detail), lack keratodonts (tooth rows). Given that many features of the tadpoles described by Smith are synapomorphies with larvae of many other groups, we presume that this description is erroneous. Furthermore, Smith does not mention the fossorial habitat of the two tadpoles, which is their most conspicuous feature. Unfortunately, Smith’s description could not be validated due to the loss of his specimens. We have failed to recover them from any potential museum collections (Natural History Museum, London and Zoological Survey of India, Kolkata).

The unusual morphological characters of Micrixalus herrei show convergence with the fossorial forms that are currently known globally. Here we discuss some of the unique features and morphological adaptations of Micrixalus herrei tadpoles that correlate with a fossorial habit.

Gayani Senevirathne, Sonali Garg, Ryan Kerney, Madhava Meegaskumbura and S. D. Biju. 2016. Unearthing the Fossorial Tadpoles of the Indian Dancing Frog Family Micrixalidae. PLoS ONE. DOI: 10.1371/journal.pone.0151781

Indian dancing frog's secretive tadpoles unearthed from sand beds
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[Herpetology • 2016] Frankixalus, A New Rhacophorid Genus of Tree Hole Breeding Frogs with Oophagous Tadpoles

Frankixalus jerdonii (Günther, 1876) 

Genus Frankixalus [gen. nov.] Biju, Senevirathne, Garg, Mahony, Kamei, Thomas, Shouche, Raxworthy, Meegaskumbura & Van Bocxlaer, 2016

 A male Frankixalus jerdonii emerges from a tree hole about 5 meters high. 

PHOTOGRAPH BY S.D. Biju || DOI: 10.1371/journal.pone.0145727

Abstract

Despite renewed interest in the biogeography and evolutionary history of Old World tree frogs (Rhacophoridae), this family still includes enigmatic frogs with ambiguous phylogenetic placement. During fieldwork in four northeastern states of India, we discovered several populations of tree hole breeding frogs with oophagous tadpoles. We used molecular data, consisting of two nuclear and three mitochondrial gene fragments for all known rhacophorid genera, to investigate the phylogenetic position of these new frogs. Our analyses identify a previously overlooked, yet distinct evolutionary lineage of frogs that warrants recognition as a new genus and is here described as Frankixalus gen. nov. This genus, which contains the enigmatic ‘Polypedates’ jerdonii described by Günther in 1876, forms the sister group of a clade containing Kurixalus, Pseudophilautus, Raorchestes, Mercurana and Beddomixalus. The distinctiveness of this evolutionary lineage is also corroborated by the external morphology of adults and tadpoles, adult osteology, breeding ecology, and life history features.

Fig 1. Bayesian consensus phylogram showing phylogenetic relationships among 86 taxa representing all known rhacophorid genera and one outgroup species.
Numbers above the branches represent Bayesian Posterior Probabilities, numbers below the branches represent Maximum Likelihood bootstrap values. Clade representing Frankixalus gen. nov. is shown in red. The specimen that was assigned to “Theloderma moloch” by Li et al. [2009] is indicated by an asterisk. Colors of taxa labels represent the reproductive modes: blue, terrestrial foam-nesting, exotrophic tadpoles; orange, terrestrial gel-nesting, exotrophic tadpoles; green, terrestrial direct-developing, endotrophic tadpoles; cyan, aquatic gel-nesting, exotrophic tadpoles. The new genus Frankixalus is also a terrestrial gel-nesting form.

DOI: 10.1371/journal.pone.0145727

Fig 2. A–C, Frankixalus jerdonii in life.
(A) dorsolateral view of an adult male (BNHS 5976), (B) an adult male (SDBDU 2009.271) emerging from a tree hole, (C) frontal view of an adult male (BNHS 5977). D–H, A composite showing the breeding habitat of Frankixalus jerdonii. (D) Evergreen forest at Mawphlang in East Khasi Hills district of Meghalaya state, (E) close-up of a tree hole opening located 3.4 meters above the ground, (F) oviposition site with eggs adhered to the inner vertical walls of the tree hole above the water level, and arrow pointing towards an adult female found submerged about 1 cm below the water surface, (G) unpigmented gel-encapsulated eggs, (H) premetamorphic larva inside the water-filled tree hole.

DOI: 10.1371/journal.pone.0145727 

Taxonomic treatment

Amphibia Linnaeus, 1758
Anura Fischer von Waldheim, 1813

Rhacophoridae Hoffman, 1932
Rhacophorinae Hoffman, 1932

Frankixalus gen. nov.

Etymology: The genus is named after Prof. Franky Bossuyt of the Vrije Universiteit Brussel (Belgium), as a token of appreciation for his contribution to amphibian research and herpetology education, and in particular for the valuable role he played in the scientific career of SDB and IVB. The generic epithet is derived from the name ‘Franky’ (used as a noun in the nominative singular) in conjugation with the genus name ‘Ixalus’ Duméril & Bibron, 1841, often used as a suffix in rhacophorid generic names. For the purposes of nomenclature, the gender of this genus is male.

Suggested common name: Franky’s tree frogs

Type species: Polypedates jerdonii Günther, 1876

'Polypedates' jerdonii =  Frankixalus jerdonii (Günther, 1876)

Boulenger, G. A. 1882. Catalogue of the Batrachia Salientia s. Ecaudata in the collection of the British Museum. 2d ed.  archive.org/stream/catalogueofbatra00brituof

Diagnosis: We consider Frankixalus to consist of the most inclusive clade that contains Frankixalus jerdonii comb. nov. but not Kurixalus eiffingeri. Frankixalus currently contains two species, F. jerdonii (Günther, 1876) and a currently unidentified species.

Frankixalus can be distinguished from the other rhacophorid genera by the combination of the following characters: medium-sized adults (male SVL 37.1–42.1 mm, N = 11; female SVL 46.8 mm, N = 1), webbing medium (foot webbing: I2––2+II1+–21/4III1+–11/2IV11/2−1+V; hand webbing: I1–1+II1+–2+III2––1+IV); creamy-white, gel-encapsulated eggs without pigmentation are laid in tree holes (phytotelm-breeding) where they also undergo development. The tadpole is oophagous and lacks keratinized tooth rows. The two currently included species are geographically restricted to high altitudes (approximately 1100–1600 m asl) in Northeast India and adjoining regions in China.

Fig 5. Geographic distribution of Frankixalus in Northeast India and China.
 Circle = Frankixalus jerdonii, square = Frankixalus sp.

DOI: 10.1371/journal.pone.0145727

Fig 2. A–C, Frankixalus jerdonii in life. (A) dorsolateral view of an adult male (BNHS 5976), (B) an adult male (SDBDU 2009.271) emerging from a tree hole, (C) frontal view of an adult male (BNHS 5977). D–H, A composite showing the breeding habitat of Frankixalus jerdonii. (D) Evergreen forest at Mawphlang in East Khasi Hills district of Meghalaya state, (E) close-up of a tree hole opening located 3.4 meters above the ground, (F) oviposition site with eggs adhered to the inner vertical walls of the tree hole above the water level, and arrow pointing towards an adult female found submerged about 1 cm below the water surface, (G) unpigmented gel-encapsulated eggs, (H) premetamorphic larva inside the water-filled tree hole.

DOI: 10.1371/journal.pone.0145727 

Description of the name-bearing type

Frankixalus jerdonii (Günther, 1876) comb. nov.

Common name: Jerdon’s tree frog

Name-bearing type: Lectotype, NHM 1947.2.7.84 (ex BMNH 72.4.17.189), an adult female.

Type locality: “Darjeeling”, West Bengal, India.

Geographic distribution: Frankixalus jerdonii is widely distributed in three Northeast Indian states (Meghalaya, Manipur and Nagaland), and in the “Darjeeling” region of West Bengal. Meghalaya: East Khasi Hills district, Wahlynkien (Marai Kaphon), Cherrapunjee (1337 m asl), and Mawphlang forest (1577 m asl); Manipur: Churachandarpur district, Zaraengtung, Raenghzaeng village (1392 m asl); Nagaland: Kohima district, Sechüma village, Zubza (1470 m asl), Meriema village (1425 m asl), Seukwehii, Tseminyu village (1340 m asl); West Bengal: Darjeeling district, “Darjeeling” (1600 m asl) (Fig 5).

Natural history and breeding ecology

All males in our study were found on arboreal vegetation in montane evergreen forest (Mawphlang, Meghalaya), or secondary forests (Zaraengtung, Manipur and Zubza, Nagaland); males from Zubza were collected from inside bamboo poles with slits. Breeding activities of Frankixalus jerdonii take place between May–August. Males of F. jerdonii were heard calling at night (between 18:00–22:00 hours) from tree holes located at heights ranging from 0.8–5.5 m at Mawphlang forest, Meghalaya (in June 2009) soon after sporadic rain showers. The habitat at this locality is composed of an evergreen forest with sparse undergrowth, consisting of scattered shrubs and herbs (Fig 2D). The trunks of hardwood trees in these montane evergreen forests usually have large growths of bryophytes (Fig 2E). Amplexus was not observed. Freshly laid egg clutches (unpigmented, gel-encapsulated) were found adhering on the inner walls of a tree hole about 5 m above the ground (Fig 2F and 2G). In total, nine nest sites were observed in tree hollows, with tree diameters of about 10–30 cm (measured at the height of the hole). Occupied tree holes had openings oriented both horizontally (N = 5) and vertically (N = 4), usually with narrow openings, and contained water that ranged in depth from about 5–50 cm (volume of water contained ranging from 30–160 ml, N = 3). A deep layer of organic debris was observed at the bottom of some tree holes, and at two nest sites a dormant male was found submerged under water (Fig 2F). When disturbed, one male tightly wedged itself into a crevice in the bottom of the hollow. At another nest site, a female (not collected) was observed submerged in water. Eggs were observed between 0.3–10 cm above the water surface, were round, diameter measuring 2.0 ± 0.1 mm, N = 18, with a thick jelly layer of about 0.2–0.4 mm. Clutch size varied from 16–30 eggs per mass (2.5–5.6 cm, N = 7). During repeated surveys at the same site between 27–29 June 2009, we also observed tadpoles of various sizes (stages 10–44) inside the water-filled tree holes

Tadepole of Frankixalus jerdonii, oral disc with papillae demarcating its margins, shown in frontal view of a stage 36 tadpole

DOI: 10.1371/journal.pone.0145727

Fig 3. Various life history stages of Frankixalus jerdonii.
 (A) lateral, (B) dorsal, (C) ventral views of a preserved stage 36 tadpole, (D) unfertilised “nutritive” eggs found inside the dissected larval gut (mean diameter = 1.0 mm), (E) oral disc with papillae demarcating its margins, shown in frontal view of a stage 36 tadpole, (F) dextral vent tube, in ventral view of a stage 26 tadpole, (G) sinistral spiracular tube, in ventral view of a stage 36 tadpole, (H) gel-encapsulated eggs (mean diameter = 2.0 mm) found on the inside wall of a tree hole, (I) dorsolateral view of a stage 44 tadpole, (J) oral disc of a live stage 36 tadpole having a bifurcated muscular tongue, shown in frontal view, (K) dorsal, (L) ventral views of a live stage 35 tadpole, (M) serrated, inverted upper jaw of a stage 37 tadpole in ventral view, (N) serrated, V-shaped lower jaw of a stage 37 tadpole in ventral view.

DOI: 10.1371/journal.pone.0145727

dorsal, ventral views of a preserved stage 36 tadpole of Frankixalus jerdonii,
unfertilised “nutritive” eggs found inside the dissected larval gut (mean diameter = 1.0 mm)

DOI: 10.1371/journal.pone.0145727

Conservation: 

The major threat for amphibians in Northeast India is disturbance of primary and secondary forests by ‘jhumming’ (slash and burn) with the purpose of cultivating crops. Several localities where Frankixalus jerdonii is reported to occur are highly disturbed and fragmented habitats. The population at Cheerapunjee in Meghalaya state was recorded from a secondary forest adjacent to a highly polluted Wahlynkien stream, individuals from Manipur were from tree stumps within a jhum field, and those from Nagaland were from a secondary forest. These threats are alarming, especially for species that have very specialized habitat requirements, such as availability of small water collections in tree holes that are crucial for their survival and reproductive success.

A male Frankixalus jerdonii emerges from a tree hole about 5 meters high. 

 PHOTOGRAPH BY S.D. Biju || DOI: 10.1371/journal.pone.0145727

Conclusion

Multiple lines of evidence from our study highlight the unique evolutionary position and life history features of Frankixalus. The description of this enigmatic lineage from the relatively unexplored northeast region of India not only emphasizes that part of this region’s biodiversity still remains poorly studied, but also underscores the need to replicate similar studies in other animal groups within this globally recognized biodiversity hotspot.

The description of this new rhacophorid genus adds to our knowledge on reproductive diversification in one of the most specious groups of neobatrachian amphibians. Such information is essential in understanding the evolution of reproductive strategies that allowed amphibians to occupy a broad variety of ecological niches. 

S. D. Biju, Gayani Senevirathne, Sonali Garg, Stephen Mahony, Rachunliu G. Kamei, Ashish Thomas, Yogesh Shouche, Christopher J. Raxworthy, Madhava Meegaskumbura and Ines Van Bocxlaer. 2016. Frankixalus, A New Rhacophorid Genus of Tree Hole Breeding Frogs with Oophagous Tadpoles. PLoS ONE. 11(1): e0145727. DOI: 10.1371/journal.pone.0145727

'Extinct' Frog Rediscovered After 150 Years, Eats Mom's Eggs 

http://on.natgeo.com/1ZMUPEV via  @NatGeo

[Herpetology • 2016] Microhyla mihintalei • A New Species of Microhyla (Anura: Microhylidae) from Sri Lanka

Microhyla mihintalei 

Wijayathilaka, Garg, Senevirathne, Karunarathna, Biju & Meegaskumbura, 2016

FIGURE 3. A, F, G. Microhyla mihintalei sp. nov. in life. A. Holotype (DZ 1553, an adult male) in dorsolateral view with a light-grey band extending from behind the eye to the groin; F. Paratype (DZ 1127, an adult male) in dorsal view; G. Paratype (DZ 1457, an adult male);
H. Microhyla rubra in life (SDBDU 2559, an adult male), from Shivanahalli, Karnataka.

DOI:  10.11646/zootaxa.4066.3.9

Abstract

Species boundaries of Microhyla rubra of India and Sri Lanka were assessed using the following criteria: genetic barcoding, morphology, and vocalization. We use a ca. 500 bp fragment of the 16S rRNA mitochondrial gene and show that there is an uncorrected pairwise distance of 2.7−3.2% between the Indian and Sri Lankan populations of M. rubra. We show that they are different in several call characteristics such as, dominant frequency, call duration, call rise time and pulse rate. Morphologically, the Sri Lankan population can be distinguished from the typical M. rubra described from southern India, by a combination of characters: body size, skin texture, and feet dimensions. We recognize the population from Sri Lanka as a new species, Microhyla mihintalei sp. nov., a widely distributed lowland species with an elevational distribution of up to 500 m a.s.l.

Keywords: Amphibia, taxonomy, barcoding, bioacoustics, multiple criteria, Sri Lanka

Microhyla mihintalei sp. nov. (Figures 1–4; Table 1)

Suggested common name. Mihintale Red Narrow-mouthed Frog.

Etymology. The species is named after Mihintale, the point of unison for two ancient cultures when Mahinda Thero (Son of Indian Emperor, Asoka) met Dewanampiya Tissa (the king of Anuradhapura, Sri Lanka) in 246 BC. Mihintale is also considered to be one of the world’s earliest sanctuaries. The species epithet mihintalei is a noun in apposition to the generic name.

Microhyla mihintalei 

Wijayathilaka, Garg, Senevirathne, Karunarathna, Biju & Meegaskumbura, 2016

FIGURE 3. A–G. Microhyla mihintalei sp. nov. in life. A–E. Holotype (DZ 1553, an adult male). A. dorsolateral view with a light-grey band extending from behind the eye to the groin; B. dorsal view showing the light reddish-brown dorsum; C. ventral view highlighting the dark blackish-brown calling patch; D. lateral view of thigh and groin; E. posterior view of thighs with irregular black markings; F. Paratype (DZ 1127, an adult male) in dorsal view; G. Paratype (DZ 1457, an adult male);
H. Microhyla rubra in life (SDBDU 2559, an adult male), from Shivanahalli, Karnataka.

DOI:  10.11646/zootaxa.4066.3.9

Holotype. Adult male (DZ 1553), Anuradhapura (8.3541°N, 80.3967°E, 90 m a.s.l) Anuradhapura Sri Lanka, collected by NW and team, 22 December 2014. 

Distribution and Natural History. Microhyla mihintalei sp. nov. is found in the lowland dry zone (Fig. 4), mostly in shaded areas, often close to stream and river banks or regions that become fairly stable ephemeral pools during the rainy season. They were observed emerging from borrows in ground to call by around 7.30 PM, slightly after the initiation of calling of M. ornata, a smaller sympatric species. Compared to M. ornata, the abundance of M. mihintalei sp. nov.is much lower, and so are the corresponding numbers of tadpoles in pools. In captivity, M. mihintalei  was  observed  digging  rapidly  into  soil  using  their  hind  feet.  This  indicates  that  they  are  active  borrowers, and not only ground-burrow utilizers. They lay eggs as loosely arranged sheets on the water surface, mainly in ephemeral pools and their tadpoles also form loose shoals. The tadpole of M. mihintalei was described by Bowatte and Meegaskumbura (2011), however, as M. rubra from Sri Lanka. 

 Nayana Wijayathilaka, Sonali Garg, Gayani Senevirathne, Nuwan Karunarathna, S. D. Biju and Madhava Meegaskumbura. 2016. A New Species of Microhyla (Anura: Microhylidae) from Sri Lanka: An Integrative Taxonomic Approach.
 Zootaxa. 4066(3): 331–342. DOI:  10.11646/zootaxa.4066.3.9

ResearchGate.net/publication/290437746_A_new_species_of_Microhyla_Anura_Microhylidae_from_Sri_Lanka_an_integrative_taxonomic_approach