New York: The world's oldest species of herbivorous marine reptile, that lived 242 million years ago in what today is southern China, is like crocodile-sized sea reptile.

"Bizarre" fossil of the animal have been discovered by scientists in 2014. Its head was poorly preserved, but it seemed to have a flamingo-like beak.

According to researchers, it is the earliest known example of a herbivorous marine reptile.

The latest research has found that the "beak" was actually part of a hammerhead-shaped jaw apparatus, which it used to feed on plants on the ocean floor.

Study co-author Olivier Rieppel from The Field Museum in Chicago said, "It's a very strange animal". "It's got a hammerhead, which is unique, it's the first time we've seen a reptile like this," Mr Rieppel noted.

The reptile is named Atopodentatus unicus -- Latin for "unique strangely toothed". But newly discovered fossils made it clearer how its "strange teeth" were actually configured.

Mr Rieppel noted, "It has similarities to other marine animals that ate plants with a filter-feeding system, but Atopodentatus is older than them by about eight million years".