Unearthing the Fossorial Tadpoles of the Indian Dancing Frog Family Micrixalidae

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.

A unique mating strategy without physical contact during fertilization in Bombay Night Frogs (Nyctibatrachus humayuni) with the description of a new form of amplexus and female call

“…As the reproduction of many species in this genus has not yet been studied, the extent of variation is likely to be even greater. Our limited understanding of this diversity is evidenced by the high number of recent publications reporting new modes of breeding and associated reproductive behaviours ( Zhang et al, 2012 ; Gururaja et al, 2014 ; Iskandar, Evans & McGuire, 2014 ; Crump, 2015 ; Seshadri, Gururaja & Bickford, 2015 ; Senevirathne et al, 2016 ). Within Nyctibatrachus , variation in the types of amplexus is especially remarkable, ranging from a normal axillary amplexus to a complete lack of physical contact between the sexes ( Kunte, 2004 ; Gururaja et al, 2014 ).…”

‘On the rocks’: reproductive biology of the endemic toadXanthophryne(Anura: Bufonidae) from the Western Ghats, India

“…After more than a century of research on the breeding biology of amphibians, we continue to discover diverse novel strategies that they exhibit to overcome various environmental challenges to successfully reproduce (Crump 2015). The underappreciated anuran diversity in the Western Ghats biodiversity hotspot has recently received much deserved attention with reports of several new species, novel reproductive behaviours and modes (Kunte 2004;Abraham et al 2013;Gaitonde and Giri 2014;Gururaja et al 2014;Seshadri et al 2015;Senevirathne et al 2016). The reproductive ecology of most Western Ghats endemics is unknown and many novel strategies and patterns are yet to be discovered.…”

“…The tropical semi-evergreen forests of the Western Ghats biodiversity hotspot have a rich assemblage of herpetofauna, especially amphibians (Daniels 1992;Bossuyt et al 2004;Gunawardene et al 2007). Although the ecology and behaviour of most anurans from the Western Ghats is largely unknown, many unique and extraordinary behaviours and adaptations in amphibians parallel this high amphibian diversity (Kunte 2004;Preininger et al 2013;Gaitonde and Giri 2014;Crump 2015;Seshadri et al 2015;Senevirathne et al 2016). The Western Ghats region is tremendously diverse across its length in climate, rainfall pattern, elevation, geology, topography, biota and landscape features (Prasad et al 2009;Watve 2013).…”

An Ecological Study of the Anurans in Tea Plantations in a Biodiversity Hotspot

“…The behavior of foot flagging is reported from individuals of Micrixalus saxicola and the behavior was observed in individuals of the genus Micrixalus, on occasion during my study (Preininger et al 2013). There was no information on the morphology of the tadpoles from the genus Micrixalus, until Senevirathne et al (2016) described the tadpoles of Micrixalus herrei. The tadpoles of the genus are fossorial until the late stages before metamorphosis (Senevirathne et al 2016).…”

“…There was no information on the morphology of the tadpoles from the genus Micrixalus, until Senevirathne et al (2016) described the tadpoles of Micrixalus herrei. The tadpoles of the genus are fossorial until the late stages before metamorphosis (Senevirathne et al 2016). On one occasion, I encountered a tadpole from the genus Micrixalus, in a stream from the Madupetty Estate.…”