‘Bunostegos’: Cow-Sized Reptile with a Knobby Skull Roamed Prehistoric Desert 260 Million Years Ago

A new study highlights the existence of a distinctive reptilian creature that roamed an isolated desert some 260 million years ago.

A new fossil unearthed from northern Niger, Africa, reveals the existence of a bizarre cow sized, plant eating reptile that roamed a vast, isolated desert some 260 million years ago. Based on its structure the cow sized reptile has been named as Bunostegos, which means 'knobby roof'.

The reptile belongs to the group of pareiasaur- large, herbivorous reptile that were common across Pangea during the Permian period.

Prior to this finding, it was known that during the Permian era our Earth was dominated by a single supercontinent Pangea. Based on identical fossils retrieved from multiple continents it is believed that various animal and plant species dispersed broadly across the land. But the new finding highlights an interesting fact that the isolated dessert in Pangea was dominated by these distinctive animals.

Pareiasaurs were known to have bony knobs on their skulls but what was different in bunostegos was that they had the largest most bulging lumpy knob on the skull. The researchers assume that they were skin covered horns found on modern day giraffes.

"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," Dr 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. The most probable use was for inter-specific (between species) or intra-specific (within species) recognition."

Initially, the researchers believed that bunostegos was an evolutionary advanced pareiasaur but on careful analysis they concluded that the bunostegos was closely related to older and more primitive pareuasaurs-this led them to believe that either the knobby noggin was due to convergent evolution or its genealogical lineage had been isolated for millions of years.

"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. 

Climatic conditions kept the bunostegos along with other reptiles, amphibians and plants constrained to the supercontinent.

Based on the geological data, researchers learnt that central Pangea was extremely dry and this prevented the animals from venturing out of the region or others crossing into it.

The study was represented in the Jorunal of Vertebrate Paleontology