A family of limbless amphibians has been discovered in the soils of northeastern India.

Credit: S. D. BIJU

Sathyabhama Das Biju at the University of Delhi and his colleagues unearthed more than 500 examples encompassing seven new species of the caecilian order of amphibians. An analysis of the animals' genomes and cranial anatomy showed that these Chikilidae (pictured with a clutch of eggs) — which measure up to 25 centimetres in length — probably first appeared during the early Cretaceous period, about 140 million years ago.

The animals' closest known relatives are in Africa. The authors suggest that, historically, caecilians are likely to have been geographically restricted, with low rates of speciation. They also warn that these and other creatures in this region of India are threatened by deforestation and rapid population growth.

Proc. R. Soc. B http://dx.doi.org/10.1098/rspb.2012.0150 (2012)