A new genus of tree hole breeding frogs has been described and named by a group of scientists led by University of Delhi researcher S. D. Biju.
An adult male of Frankixalus jerdonii is emerging out of a tree hole. Image credit: S.D. Biju.
During fieldwork in four northeastern Indian states, Dr. Biju and his colleagues discovered several populations of tree frogs with unusual characteristics, including tadpoles that feed on the mother’s eggs.
To investigate the phylogenetic relationship of these new frogs, they compared molecular data with known tree frog genera.
“To clarify the evolutionary position of the Northeast Indian tree hole breeding frogs, we performed phylogenetic analyses of nuclear and mitochondrial gene fragments totaling 3,800 characters for 86 taxa representing all major rhacophorid lineages,” the scientists explained in a paper published in the journal PLoS ONE.
Through their analyses, they identified a previously overlooked, yet distinct evolutionary lineage of frogs that the scientists recognize as a new genus.
“We demonstrate that these frogs form a distinct evolutionary lineage that warrants recognition as a new genus, and provide a detailed account of their breeding ecology, larval behavior, morphology, and osteology,” they explained.
They decided to name this new genus Frankixalus. The proposed English name is ‘Franky’s tree frog.’
“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,” Dr. Biju and co-authors said.
“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.”
Geographic distribution of Frankixalus in Northeast India and China: circle – Frankixalus jerdonii; square – Frankixalus sp. Image credit: Biju S.D. et al.
The genus currently contains two species, Frankixalus jerdonii and a currently unidentified species.
“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.”
Frankixalus frogs differ from other tree frogs in breeding, egg laying, and development. This includes having gel-encapsulated eggs, breeding in water accumulated in tree holes, egg laying on walls of tree holes, and tadpoles that devour their mother’s eggs.
“Since the new genus shows remarkable parental care behavior with specific microhabitat requirements for their survival, populations discovered from highly disturbed forests are already facing extinction threats,” Dr. Biju said.
“The distinctiveness of this evolutionary lineage is also corroborated by the external appearance, skeletal shape and life history features.”
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Biju S.D. et al. 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
