Researchers have discovered a tadpole in the Western Ghats of India that eats sand and lives in darkness till the time it turns into a frog. The discovery has been made by scientists from the University of Delhi, the University of Peradeniya, Sri Lanka and Gettysburg College, California.
The tadpole belongs to the Indian dancing frog family, Micrixalidae. They are called dancing frogs because of their nature of waving their legs signalling territorial and sexual display.
''We provide the first confirmed report of the tadpoles of the Indian dancing frog family. These tadpoles probably remained unnoticed all these years because of their fossorial [underground] nature, which in itself is a rare occurrence in the amphibian world,'' S D Biju from the University of Delhi said in a statement.
According to Dr Biju, such displays are well known, but information on these tadpoles was completely missing.
Dr Biju had in January reported in the same journal of a frog species called Frankixalus jerdonii, which was once considered a species lost to science.
The purple dancing frog tadpoles were found in the deep recesses of streambeds. With eel-like bodies and skin-covered eyes, they burrow through gravel beds. They don't have teeth but serrated jaw sheaths, which help them feed and move through sand.
The Micrixalidae tadpoles hang onto the rocks underwater with support of their mouths. According to Madhava Meegaskumbura from the University of Peradeniya, the tadpoles have ribs and whitish globular sacs that store calcium carbonate, known as ''lime sacs''. This is another unusual feature of this tadpole.
''Only four families of frogs are reported to have ribs, but we show that at least some of Micrixalidae also have ribs, even as tadpoles; this adaptation may provide for greater muscle attachment, helping them wriggle through sand,'' he said.
The research has been published in the peer-reviewed open-access journal PLOS One.