Meet India's starry dwarf frog, lone member of newly discovered ancient lineage

March 12, 2019 by Natalie Van Hoose, Florida Museum of Natural History

The starry dwarf frog is an expert hider. Plunging into leaf litter at the slightest disturbance, it has successfully evaded attention for millions of years—until now.

The thumbnail-sized species was discovered in India's Western Ghats, one of the world's "hottest" biodiversity hotspots. Scientists have named the frog Astrobatrachus kurichiyana for its constellation-like markings and the indigenous people of Kurichiyarmala, the hill range where it was found.

But A. kurichiyana is not only a new species to science. It's the sole member of an ancient lineage, a long branch on the frog tree of life that researchers have classified as a new subfamily, Astrobatrachinae.

"This is an oddball frog—it has no close sister species for maybe tens of millions of years," said David Blackburn, the associate curator of herpetology at the Florida Museum of Natural History. "With frogs, there are still ancient lineages out there awaiting discovery. This gives us one more puzzle piece to think about deep time."

Dark brown with a bright orange underbelly and speckled with pale blue dots, the frog camouflages well in wet leaf litter, and only a few individuals have been found.

"The coloration was the first thing that stood out to me, these starry patterns with a blue tinge," said Seenapuram Palaniswamy Vijayakumar, lead author of the species description and now a postdoctoral fellow at George Washington University. "We hadn't seen anything like this before."

But the starry dwarf frog nearly got overlooked in the crush of new species that Vijayakumar and his then-doctoral supervisor Kartik Shanker were finding on a series of expeditions to the Western Ghats, a 1,000-mile-long mountain range along India's southwestern coast.

Vijayakumar and Shanker, associate professor at the Indian Institute of Science, had designed a meticulous study, covering multiple elevations, habitats and hill ranges to record and map the region's frogs, lizards and snakes.

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