Shrub frog rediscovered in E Ghats, points to Lanka land link in past

Hyderabad: Scientists have rediscovered the polymorphic Sri Lankan brown-eared shrub frog in the Eastern Ghats of Andhra Pradesh. The finding, published in the international journal ‘Zootaxa,’ highlights the presence of the Sri Lankan ‘Pseudophilautus regius’, commonly known as the brown-eared shrub frog, far from its known range.
The significant rediscovery by researchers from Zoological Survey of India (ZSI), Hyderabad, in collaboration with the Andhra Pradesh Biodiversity Board, raises two major scientific issues: Lack of documentation and understanding of amphibian diversity in the Eastern Ghats and the evolutionary history of the land bridge connection between India and Sri Lanka during the Pleistocene period.

Meanwhile, ZSI announced a new regional centre in Amaravati.
The brown-eared shrub frog, initially described in 2005, is a common species in Sri Lankan forests. After two decades, the species has now been identified in the Eastern Ghats, approximately 700 km from its known range. Previously, three related species were reported from the Western Ghats, but this is the first report of a brown-eared shrub frog from the Eastern Ghats in over 220 years of amphibian research in India.
The rediscovery of the species, confirmed genetically and showing morphological colour variations, suggests a complex biogeographical history. Sri Lanka hosts 75 species of ‘Pseudophilautus’, while the Western Ghats have three, all endemic to their respective landscapes. Notably, both Sri Lanka and the Eastern Ghats are influenced by the northeast monsoon, unlike the Western Ghats, which are primarily affected by the southwest monsoon. This climatic similarity could explain the presence of some Sri Lankan amphibian species in the Eastern Ghats.
‘Pseudophilautus’ frogs, including the brown-eared shrub frog, are ‘direct developers,’ meaning they skip the free-swimming tadpole stage and emerge as miniature adults directly from eggs. This unique life cycle highlights the ecological and evolutionary significance of these amphibians.
The Eastern Ghats currently host 28 amphibian species, significantly fewer than the 253 species in the Western Ghats and 455 species in India. This disparity underscores the need for further exploration and documentation of the amphibian diversity in the Eastern Ghats. Amphibians are crucial ecological indicators, and their presence signifies a healthy ecosystem.
ZSI director Dr Dhriti Banerjee emphasized the importance of biodiversity conservation in unexplored and protected areas, particularly permanent water bodies and grasslands.