At just two centimetres long, the Starry Dwarf Frog (Astrobatrachus kurichiyana) is a midget of the amphibian world. It was discovered in the tropical rainforests of the Western Ghats, a mountain range running along the western coast of peninsular India. Secretive, nocturnal, difficult to spot, and partial to the forest’s leaf litter, it is no bigger than a human thumbnail. Indian biologists Seenapuram Palaniswamy Vijayakumar and Kartik Shanker, of the Indian Institute of Science, stumbled upon this elusive species during an expedition into the heart of the Western Ghats in 2010.

They were part of a team undertaking a large-scale survey of the amphibians and reptiles of the region. The mountains of the region are a global biodiversity hotspot, supporting a surprisingly rich and diverse collection of plants and animals, including those which are found nowhere else. The Starry Dwarf Frog has a brown back peppered with bluish dots (mostly along its sides), and a bright orange belly. The specimens captured by the team were discovered in the vicinity of Kuruchiyarmala, a mountain in the state of Kerala. It was almost a decade later that the identity of the tiny frog was revealed.

A team of researchers including Alex Pyron (of the George Washington University), and David Blackburn and Edward Stanley (of the Florida Museum of Natural History) used the CT scans of the frog to pin down its location on the amphibian family tree. The genus Astrobatrachus is monotypic, with the Starry Dwarf Frog as the sole member. It is a relic, the sole survivor of an ancient lineage of frogs that lived in South India several millions years ago. Its nearest relatives include the 30 species of night frogs of the genus Nyctibatrachus of the Western Ghats and the 2 species of the genus Lankanectes of Sri Lanka’s Knuckles Mountains. Together the three genera – Astrobatrachus, Nyctibatrachus and Lankanectes form the family Nyctibatrachidae, endemic to southwestern India and Sri Lanka.

Image Attribution: The image above, sourced from Wikimedia Commons, shows a Starry Dwarf Frog (of the genus Astrobatrachus).