Hylarana caesari or the Maharashtra Golden-backed Frog named after Dr Caesar Sengupta (below) in 2014. Pic Courtsy/SD Biju

Last year, when amphibian biologist SD Biju and his team of students were looking for frogs in the forests of Meghalaya, they heard what sounded like "a musical orchestra playing on the treetops". This led them to rediscover Frankixalus jerdonii, a unique tree frog residing in bark holes, believed to have been extinct more than a century ago. In the past 15 years, the 53-year-old Delhi-based researcher, also dubbed as the frogman of India, and his team have discovered 89 of India's 388 frog species. These include a meowing night frog, dancing frog, pig-nosed Indian purple frog found in the Western Ghats and the smallest Indian frog, which can sit on a five-rupee coin.