The fossilised remains of a squirrel-sized animal recently unearthed in Inner Mongolia is believed to be an example of a proto-mammal, providing scientists insights into how mammals first evolved, the Guardian reports.
Named Megaconus, or “large cusp”, after its distinctive teeth, the animal was unearthed in Inner Mongolia where it had been preserved in volcanic ash that settled in a freshwater lake. It is thought to be an early relative of mammals, and has some mammalian features, while others are more commonly seen in reptiles.
Megaconus is believed to have been a furry animal with a keratinous spur on its hind ankle that was likely used to poison prospective predators. The creature is not a true mammal, still having primitive middle ear bones attached to the jaw as in reptiles.
The animal belongs to a group called the haramiyids, whose existence was previously based on the scant fossil evidence of isolated teeth. Megaconus had long, rodent-like teeth able to chew plants and munch on insects and worms.
“The teeth have been studied since the 19th century, but nobody had an idea what these animals looked like,” said Thomas Martin, a scientist on the team at the University of Bonn.
Another team of scientists, also writing in Nature, described another haramiyid, named Arboroharamiya, which possessed long toes and fingers. The team claim Aboroharamiya as a true mammal, dating the origin of the class of animals to over 200 million years ago.
[Image credit: April Isch]