Knobby Bunostegos Lived Isolated in Pangea Desert

A previously unknown genus of bulbous-faced reptile that roamed the Earth about 260 million years ago has been described in the latest edition of the Journal of Vertebrate Paleontology.

The newly unearthed fossils from the desert of what is now northern Niger describe a previously undocumented pareiasaur -- a plant-eating creature that lived in the Permian period, about 250 million to 300 million years ago when earth was dominated by a single supercontinent known as Pangea.

Bunostegos, as the new creature is called, was about the size of a cow. It gets its name (which means "knobby roof") from the boney knots covering its head. Such bony knobs are found on most pareiasaurs, but they likely did not function as armor.

"We can't say for sure, but it is most likely that the bony knobs on the skull of pareiasaurs did not serve a protective function," Linda Tsuji from the University of Washington in Seattle told BBC News.

"They vary quite markedly in size and shape between different species, with some species lacking prominent knobs entirely, so I think that they were purely ornamental," Tsuji said, adding that the most probable use for the knobs was as interspecies identifying markers.

Researchers' analysis determined that the Bunostegos was genetically a closer relative of the more primitive pareiasaurs, leading them to believe the creatures lived in isolation for millions of years, corralled in a desert in the middle of Pangea with its own unique fauna

"Our work supports the theory that central Pangea was climatically isolated, allowing a unique relict fauna to persist into the Late Permian," said Christian Sidor, another author of the paper on Bunostegos.

The researchers believe Bunostegos was isolated with other species of reptiles, amphibian and plants in a central, extremely dry area of the supercontinent. The conditions of ancient central Pangea were enough to keep the creatures living within it from going out and also kept other creatures from coming in. The long period of isolation allowed the Bunostegos to evolve its unique features.

"Research in these lesser-known basins is critically important for meaningful interpretation of the Permian fossil record," Gabe Bever, a paleontologist who was not involved with the study, said in a statement. "Our understanding of the Permian and the mass extinction that ended it depends on discovery of more fossils like the beautifully bizarre Bunostegos."