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Unearthing the Fossorial Tadpoles of the Indian Dancing Frog Family Micrixalidae.

Senevirathne G, Garg S, Kerney R, Meegaskumbura M, Biju SD - PLoS ONE (2016)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology & Biotechnology, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka.

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.

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Double-stained specimens of Micrixalus herrei life history stages.(A) Chondrocranium, dorsal view at stage 36; (B) vertebral column, ventral view at stage 36; (C) vertebral column, lateral view at stage 36; (D, E) stage 42 and (F, G) stage 46 metamorphs with lime sacs extending along the extradural space of the vertebral column.
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pone.0151781.g005: Double-stained specimens of Micrixalus herrei life history stages.(A) Chondrocranium, dorsal view at stage 36; (B) vertebral column, ventral view at stage 36; (C) vertebral column, lateral view at stage 36; (D, E) stage 42 and (F, G) stage 46 metamorphs with lime sacs extending along the extradural space of the vertebral column.

Mentions: Description of the larval chondrocranium is based on stained-specimens of stage 36 (N = 2). The chondrocranium is narrow and oblong-shaped (Fig 5A). The maximum width is 67.34% of its total length and its widest part is at the posterior end of subocular bar of the palatoquadrate (Fig 5A). The jaw suspension creates an angle of 30° with the floor of the neurocranium resulting in a relatively flattened skull.


Unearthing the Fossorial Tadpoles of the Indian Dancing Frog Family Micrixalidae.

Senevirathne G, Garg S, Kerney R, Meegaskumbura M, Biju SD - PLoS ONE (2016)

Double-stained specimens of Micrixalus herrei life history stages.(A) Chondrocranium, dorsal view at stage 36; (B) vertebral column, ventral view at stage 36; (C) vertebral column, lateral view at stage 36; (D, E) stage 42 and (F, G) stage 46 metamorphs with lime sacs extending along the extradural space of the vertebral column.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814069&req=5

pone.0151781.g005: Double-stained specimens of Micrixalus herrei life history stages.(A) Chondrocranium, dorsal view at stage 36; (B) vertebral column, ventral view at stage 36; (C) vertebral column, lateral view at stage 36; (D, E) stage 42 and (F, G) stage 46 metamorphs with lime sacs extending along the extradural space of the vertebral column.
Mentions: Description of the larval chondrocranium is based on stained-specimens of stage 36 (N = 2). The chondrocranium is narrow and oblong-shaped (Fig 5A). The maximum width is 67.34% of its total length and its widest part is at the posterior end of subocular bar of the palatoquadrate (Fig 5A). The jaw suspension creates an angle of 30° with the floor of the neurocranium resulting in a relatively flattened skull.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology & Biotechnology, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka.

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.

Show MeSH
Related in: MedlinePlus