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A mother with her egg clutch and hatchlings; (top) Rachunliu Kamei (in cap) and Sathyabhama Das Biju (with spectacles) with two assistants in Meghalaya. Picture by S.D. Biju |
New Delhi, Feb. 21: Biologists have discovered a new family of legless amphibians in northeastern India, adding a clan to the nine families hitherto known to science.
The amphibians, called caecilians, were found in farms and backyards across Arunachal Pradesh, Assam, Meghalaya, Mizoram and Nagaland. A study on them revealed ancient genetic links to Africa, researchers said. Till now, there were nine families of amphibians known to science.
Scientists from the University of Delhi and their colleagues from Belgium and the UK announced their discovery in a paper that appeared today in the journal Proceedings of the Royal Society B.
The new family of caecilians, given the name Chikilidae, is genetically closer to the African caecilians than to other legless amphibians found so far across peninsular India, the scientists said.
“They appear to have moved into the Northeast millions of years ago when India was still connected to Africa, and then evolved independently, isolated from amphibians in peninsular India,” said Sathyabhama Das Biju, a senior zoologist in the University of Delhi. He said the name Chikilidae was derived from Garo, a northeastern tribal language.
Biju, India’s leading amphibian researcher, and his PhD student Rachunliu Kamei, originally from Manipur, discovered the new family during a search for amphibians in the Northeast between 2006 and 2010. The search yielded over 500 caecilians at 58 sites among the 238 localities surveyed.
The scientists classified the Chikilidae as a new family after studies revealed that these creatures had distinctive morphology — physical features — and a unique position on the genetic tree of amphibians.
The Chikilidae, which have a snake-like appearance, maintain a secret, hidden life beneath the soil, Biju said. He said the amphibians displayed an “intriguing and highly specialised reproductive behaviour”.
The mother built underground nests for eggs and guarded her clutch by coiling around them until the embryos hatched, which took two to three months. The eggs underwent direct development — the creatures fed on the yolk reserves and emerged as miniature adults. An adult could be about 10 inches long, Biju said in a statement describing the new family.
Indirect evidence suggests the creatures feed on earthworms.
“Unfortunately, because of their snake-like appearance, they are sometimes killed. But caecilians are neither venomous nor are they snakes,” Biju said. “They never bite, and they open their mouth only for feeding.”
Biju told The Telegraph: “The take-home lesson from this find is that the Northeast is not merely a gateway to the biodiversity of southeast Asia as it is often portrayed to be. This discovery is a signal that the Northeast itself is enormously rich in biodiversity. India needs to invest more energy and resources into exploring and conserving the biodiversity there.”
Genetic studies on the new family suggested that the animal had an ancient lineage and its closest relatives were in Africa. The finding also suggested that the Chikilidae had branched out from species yet unknown to science.
The scientists said the genetic tree of caecilians suggested that the two families — Chikilidae and Herpelidae — diverged about 140 million years ago, around the time the Indian landmass separated from the African continent.
The discovery of a new family of vertebrates, the first from Northeast India, suggested that this region “has a potentially rich but still hidden biodiversity in need of improved inventories”, the researchers wrote in their paper.
They have called for further exploration and conservation initiatives because the region’s biodiversity is under “high threat from the growing resident human population and rapid deforestation”.
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