Mizoram adds two new frog species to science, one from a university campus

Mizoram has yielded two amphibian species new to science, one of them a toad found on the state's highest peak and the other a frog that had been living on a university campus for more than twenty years under a mistaken identity.

The two species, Duttaphrynus phawngpui and Ingerana aizawl, have been named after Phawngpui, also called the Blue Mountain, and the state capital Aizawl respectively. The findings appear in two studies published in the journals Taprobanica and Zootaxa.

The toad was recorded at elevations above 2,000 metres inside Phawngpui National Park. It is a medium-sized animal, reaching up to 56 mm in body length, with yellowish-brown to earthy-brown skin marked by irregular dark blotches. A pale stripe runs down its back, and its legs carry crossbars. It can be told apart from close relatives such as Duttaphrynus stuarti, Duttaphrynus chandai and Duttaphrynus dhara by the absence of a clearly visible eardrum and of most of the bony ridges usually seen on the skull.

Three independent lines of evidence — sequencing of a mitochondrial gene, statistical analysis of body measurements, and visual comparison with museum specimens of its nearest relatives — converged to confirm that the population is genetically distinct rather than a variant of a known species.

The discovery strengthens the idea that isolated mountain peaks function as "sky islands", where populations evolve separately over long periods. The toad is so far known from a single mountaintop, a limited range that worries conservationists as the climate warms, since species confined to high ground have no higher habitat to move to. The find also points to how much amphibian diversity may remain undocumented in the under-surveyed uplands of Mizoram and the wider Indo-Burma region, among the world's most biodiverse and most threatened areas.

The second species had a quieter history. For over two decades, a short, stocky frog measuring 22–26 mm and frequently seen on the Mizoram University campus was assumed to be Ingerana borealis, a widespread species. When a later taxonomic reassessment cast doubt on that identity, researchers re-examined the campus population using genetic sequencing along with body shape, size, skin texture and mating calls.

The frog, which has a distinctly bumpy and wrinkled back, a clearly visible domed eardrum and small toe pads, was found to differ from its closest relatives by up to 6.6%. It was named Ingerana aizawl. The species lives along small forest streams and calls at night, each call a rhythmic series of twelve short notes. Mating takes place during the monsoon, with pairs clasped together, though no eggs have yet been found in the wild or produced by captive pairs.