Cow-Sized Pre-Reptile May Have Been First To Walk On 4 Legs 260 M Years Ago

It was a first of its kind. One "ancient pre-reptile" was probably one of the first animals to stand on four legs---like any cow, lion or hippo, according to hngn.

So this Bunostegos akokanensis, as he is called today, was quite a cool number in the supercontinent of Pangea 260 million years ago, Brown University  reported.

His contemporaries at the time were pareiasaurs with limbs that "jutted out from the sides of their bodies and slanted down from the elbow downwards."

However, Bunostegos seemed to be pretty unique, reveals the study.

"A lot of the animals that lived around the time had a similar upright or semi-upright hind limb posture, but what's interesting and special about Bunostegos is the forelimb, in that it's anatomy is sprawling----precluding and seemingly directed underneath its body---unlike anything else at the time," said Morgan Turner, who was the main author of the study. "The elements and features within the forelimb bones won't allow a sprawling posture. That is unique."

This fellow even seemed to have an interesting humerus that was not twisted like other sprawlers. It seems to suggest that alignment of the elbow and shoulders beneath the body can enable to get the foot reach the ground.

While sprawling pareiasaurs showed mobility from the elbow, Bunostegos seemed to exhibit limited mobility in his elbows. Even as the animals' forearm bones seemed to make a hinge-like joint that could swing both ways, somewhat like a human knee, but not from side to side.

There is hope that more animals with the same kinds of posture who lived during the early period of the earth will someday come to light.

"Posture, from sprawling to upright, is not black or white, but instead is a gradient of forms," Turner said. "There are many complexities about the evolution of posture and locomotion we are working to better understand every day. The anatomy of Bunostegos is unexpected, illuminating, and tells us we still have much to learn."

The study was published in a recent edition of the Journal of Vertebrate Paleontology.