Kawingasaurus is a very ancient therapsid with a very developed brain

Kawingasaurus Skull (Image courtesy Michael Laaß / Verlag Wiley-VCH)
Kawingasaurus Skull (Image courtesy Michael Laaß / Verlag Wiley-VCH)

An article published in the “Journal of Morphology” describes a research on the skull anatomy of Kawingasaurus fossilis, a therapsid that lived just over 250 million years ago. Paleontologist Michael Laaß of the Institute of General Zoology at the University of Duisburg-Essen (UDE) and Dr. Anders Kaestner of the Paul Scherrer Institute in Switzerland examined a skull of this animal noting a structure similar to the neocortex, the most recent part of mammals’ brain.

Kawingasaurus is a part of the dicynodont (Dicynodontia) grup, a infraorder of therapsids (Therapsida), a superorder which includes those considered the ancestors of mammals, included in the infraorder of cynodonts (Cynodontia). Therapsids appeared in the Middle Permian and got extinct during the Mesozoic era and had a mix of reptile and mammalian features.

Kawingasaurus is a species discovered in Tanzania in 1936 and initially its fossils were mistaken for specimens of Cistecephalus, another dicynodont. Only in 1972 new fossil studies led to their new classification with the creation of the Kawingasaurus genus. They were herbivores with a length that could probably reach 50 centimeters. However, the most interesting part of their anatomy was their skull and in this new research the skull of a specimen that lived just over 250 million years ago, during the Upper Permian period, was reproduced through a tomographic technique.

The 3D reconstruction allowed a virtual examination to understand what kind of shape a Kawingasaurus could have and how it was structured. The first result was that its volume was about twice, if not triple, than that of other non-mammalian therapsids. The researchers also found that this animal had a big forebrain with two distinct hemispheres and a structure similar to mammals’ neocortex.

This brain so developed can be explained by thinking that Kawingasaurus was a burrower that needed senses with special adaptations to thrive in its underground life. Its sight had to be good to see in dim light and its sense of touch had to be developed as well. Its large inner ear vestibules indicate that its ears were suitable to perceive the vibrations in the ground.

The development of Kawingasaurus’ senses required a proper brain and probably it evolved to get adapted to them with a neocortex-like structure. This is a scenario similar to that suggested for the origin of neocortex in mammals. This is also very interesting because Kawingasaurus isn’t among mammalian ancestors and this means that such a structure developed more than once independently.

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