Western Ghats unveil its amphibian diversity

T. Nandakumar, Thiruvananthapuram
The Hindu, November 17, 2016

Reinforcing the importance of the Western Ghats as a valuable reservoir of amphibian diversity, researchers from the University of Delhi have reported two new species of leaping frogs from Kerala and Karnataka.

The new species - Indirana paramakri and Indirana bhadrai - have been reported in the latest issue of PLOS One, an open access scientific journal published by the Public Library of Science.

The authors, Sonali Garg and S.D. Biju, conducted DNA barcoding of over 200 samples to provide new estimates of the species diversity and distribution of Indirana frogs, an ancient genus endemic to the Western Ghats biodiversity hotspot.

The specimens of Indirana paramakri were collected from wet rocks near streams and under leaf litter in disturbed forest areas in Settukunu and Sugandhagiri, north of the Palakkad Gap in Wayanad district.

The species epithet is derived from the Malayalam words ‘para’ meaning rock and ‘makri’ for frog, referring to the occurrence of the species on rocky terrain. Reddish brown with a black band extending from the nostril to the sides, the species is distinguished by its small snout- vent size and unique toe webbing.

Named after its habitat, Indirana bhadrai is currently known only from the Muthodi forest in the Bhadra Wildlife Sanctuary, located north of the Palakkad Gap in Karnataka. The frogs were found on leaf litter in a secondary forest.

Distinguished by a pointed snout and toe webbing, I. bhadra is light brown with irregular dark brown blotches along the dorsal skin folds and a dark greyish-brown band between the eyes.

According to Dr. Biju, though several studies have been carried out on the Indirana genus, taxonomic ambiguities have remained an impediment for proper identification of species and estimates of diversity and distribution. “Our study provides new distribution records for all the currently known Indirana species.”

The researchers have outlined a distribution trend suggesting genetic isolation between populations of the amphibians found north and south of the Palakad Gap, indicating the role of elevational discontinuities in distribution. They have proposed a reassessment of the IUCN categorisation of all species for effective conservation of these relic frogs.