The fossilized skull of an ancient pygmy sea cow recently discovered in Madagascar could shed some light on a prehistoric period that remains mysterious to scientists. 

Estimated to be about 40 million years old, the nearly complete skull comes from an ancient “dugong”. 

Thought to be among the world’s first fully aquatic sea cows, these creatures are a stepping stone between primitive land-dwelling mammals and the sea cows of today, which include both manatees and dugongs.

"The fossils of this ancient sea cow are unique in that it has a full set of relatively unspecialized teeth whereas modern sea cows have a reduced dentition specialized for eating sea grass, and most fossil species already show some degree of reduction,” says professor Karen Samonds of McGill University in Quebec.

This prehistoric pygmy sea cow, which at about 7 feet long was significantly smaller than its modern-day descendants, may be the key to unlocking the secrets of an 80-million-year gap in the fossil record of Madagascar.

The newly discovered species, named Eotheroides lambondrano, is unusual in another way: its closest relatives would have lived in what is now India and Egypt.

"My hope with the discovery of these fossils is that they will illuminate how, when and from where Madagascar's modern animals arrived, helping us understand how Madagascar accumulated such a bizarre and unique set of modern animals,” Samonds told Science Daily.