India’s newest frog evolved 60 million years ago
The discovery of the starry dwarf frog, a nocturnal amphibian that lives under leaf litter on a mountain top in Kerala’s Wayanad Sanctuary.
It is just 2 cm long and sports pale blue spots and brilliant orange thighs. Its physical, skeletal and genetic characteristics were compared with specimens of similar species in museum collections across the world. While scans of its skeletons showed it to be completely different from any other similar-sized frog seen in Wayanad, some of its physical characteristics (such as its triangular finger- and toe tips) closely resembled frogs in South America and Africa.
Genetic studies, however, revealed a different story: its closest relatives are the Nycibatrachinae group of frogs that dwell in the streams of Western Ghats, and the Lankanectinae frogs of Sri Lanka.
The new species was named as the starry dwarf frog Astrobatrachus kurichiyana (genus Astrobatrachus after its starry spots and kurichiyana in honour of the Kurichiya tribal community who live in the area). It is not only a new species but different enough to be assigned to a new ‘subfamily’.
Genetic analysis reveal that the species is at least 60 million years old.
The presence of Astrobatrachus and other ancient lineages in the southern Western Ghats highlights the mountain range’s role as a historical refugium and as an important centre of diversification.
Though additional surveys would be necessary, the starry dwarf frog is currently known only from Wayanad’s Kurichiyarmala peak, outside legally protected areas.