Unraveling a Mystery: Bird Brains Left Other Dinosaurs Behind - SciTechDaily

A transparent 3D model of the fossil bird skull and brain (in pink).

Credit: Christopher Torres / The University of Texas at Austin.

Research on a newly discovered bird fossil led by The University of Texas at Austin found that a unique brain shape may be why the ancestors of living birds survived the mass extinction that claimed all other known dinosaurs.

The fossil is about 70 million years old and has a nearly complete skull, a rare occurrence in the fossil record that allowed the scientists to compare the ancient bird to birds living today.

A fossil skull of Ichthyornis, a bird that lived 70 million years ago during the late Cretaceous Period.

Credit: Christopher Torres / The University of Texas at Austin.

The fossil is a new specimen of a bird named Ichthyornis, which went extinct at the same time as other nonavian dinosaurs and lived in what is now Kansas during the late Cretaceous Period.

The intact skull let Torres and his collaborators get a closer look at the brain.

With CT-imaging data, the researchers used the skull of Ichthyornis like a mold to create a 3D replica of its brain called an endocast.

The ancestors of living birds had a brain shape that was much different from other dinosaurs (including other early birds).

This suggests that brain differences may have affected survival during the mass extinction that wiped out all nonavian dinosaurs.

Credit: Christopher Torres / The University of Texas at Austin.

The researchers found that the brain of Ichthyornis had more in common with nonavian dinosaurs than living birds.

In particular, the cerebral hemispheres – where higher cognitive functions such as speech, thought and emotion occur in humans – are much bigger in living birds than in Ichthyornis.

“This fossil helps bring us much closer to answering some persistent questions concerning living birds and their survivorship among dinosaurs.”.