London, Feb 21 (IANS): A detailed investigation of all Chinese specimens of Pareiasaurs -- the "ugliest fossil reptiles" -- shows that there are similarities between Chinese fossils and those found in other parts of the world.

Pareiasaurs have been reported from South Africa, Europe (Russia, Scotland, Germany), Asia (China), and South America, but it is not known whether there were distinct groups on each of these continents.

In a new study published in the Zoological Journal of the Linnean Society, professor Mike Benton of Bristol's School of Earth Sciences said the similarities indicated that the huge herbivores were able to travel around the world despite their lumbering movement.

"Up to now, six species of pareiasaurs had been described from China, mainly from Permian rocks along the banks of the Yellow River between Shaanxi and Shanxi provinces," Professor Benton said.

"I was able to study all of these specimens in museums in Beijing, and then visit the original localities. It seems clear there were three species and these lived over a span of one to two million years," he added.

Pareiasaurs were hefty animals, two to three metres long, with massive, barrel-shaped bodies, short, stocky arms and legs, and tiny head with small teeth. Their faces and bodies were covered with bony knobs.

They lived in damp, lowland areas, feeding on huge amounts of low-nutrition vegetation.

The new study confirms that the three Chinese pareiasaur species differed from each other in body size and in the shapes of their teeth.