Ancient lineage traced to East, West parts of Africa

Scientists have discovered a new family of limbless amphibians from northeast India with their ancient lineage traced to eastern and western parts of Africa, a relationship preserved from the time the southern continents broke up more than 150 million years ago.

Kerala-born Delhi University scientist S.D. Biju and co-researchers from India and Europe have reported their discovery in the latest issue of the Proceedings of the Royal Society of London B. They have named the new family as Chikilidae and the new genus as Chikila, deriving the name from the Northeast Indian tribal language of Garo.

Until this discovery, there were only nine known families of legless amphibians, also called caecilians, found across the wet tropical regions of Southeast Asia, India, Sri Lanka, parts of East and West Africa, the Seychelles and northern and eastern parts of South America. From morphological and DNA analyses, the researchers show that the new family had evolved independent of other species of caecilians starting from the time of the dinosaurs. Its closest relatives now live in Africa.

‘Discovery of the year’

“This is the amphibian discovery of the year,” said Darrel Frost, Curator-in-charge, American Museum of Natural History, in a message to The Hindu when queried about the significance of the find.

“An Indian amphibian species with ancient African roots makes it clear that India has some very special lessons to teach us… Not just a lucky find, but the product of extremely diligent fieldwork by a team of world-class scientists.”

Don Church, President and Director of Wildlands Conservation, Global Wildlife Conservation, said in another message: “This study underscores the urgent need for increased biological exploration in places that have not been previously thought to hold major clues to the history of life on our planet. I was surprised and fascinated that yet another entirely new family of amphibians that crawled the earth alongside dinosaurs has only just now been discovered by scientists in the 21st century…”

Said Dr. Biju: “We also found that Chikilidae is a radiation of multiple species as yet unknown to science. The discovery comes following soil-digging surveys spread over five years in nearly 250 locations in the northeast States of Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Tripura, Sikkim and West Bengal as part of my student Rachunliu G. Kamei's PhD work.”

The collaborative team that reports the find includes, besides Dr. Biju and Ms. Kamei, Ashish Thomas and Suresh Babu of University of Delhi; David J. Gower, Emma Sherratt and Mark Wilkinson of Natural History Museum, London; and Franky Bossuyt and Ines Van Bocxlaer of Vrije University, Brussels.

Chikilidae is a group of extremely dedicated burrowers. They exhibit an intriguing and highly specialised reproductive behaviour. The mother builds underground nests for her eggs and coils around them. The embryos hatch in about 2-3 months. The eggs undergo direct development, feeding on the yolk reserves and come out as miniature adults without an intervening free-swimming larval stage that is usual of amphibians in general, Dr. Biju said.

Poorly studied region

This discovery puts the spotlight on northeast India as a poorly studied region likely to harbour still more ancient lineages of organisms found nowhere else on Earth, he said.