MELBOURNE - The fossilised remains of a previously unknown species of prehistoric crocodile that lived 40 million years ago have been unearthed in a lake bed of eastern Australia, researchers said here yesterday.

The almost complete skulls, one lower jaw, and parts of the legs, ribs and claws of two of the crocs have excited scientists studying the evolution of one of Australia's more dangerous killers.

"It's important because it belongs to the earliest known genus of what's called Mekosuchine - a big group of extinct crocodiles that dominated Australia and developed a large degree of diversity," Monash University researcher Lucas Buchanan said.

"He is like the oldest, most primitive brother of Mekosuchine crocodiles, the first kid on the block."

Buchanan, who was the first to identify the fossilised remains found near Gladstone in the southeastern state of Queensland, said the discovery shed light on the "bigger picture" of crocodile evolution.

Not much is known about crocodiles that lived between 30 and 65 million years ago. - Sapa-AFP