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Brain differences may have affected survival during the mass extinction that wiped out all non-avian dinosaurs.
(Christopher Torres / University of Texas at Austin)
US researchers have discovered a new bird fossil that has shown that a unique brain shape could be the reason the ancestors of living birds survived the mass extinction that claimed the lives of all other dinosaurs known 66 million years ago.
A team from the University of Texas at Austin, USA, discovered the fossil, which is nearly 70 million years old and has a nearly complete skull, a rare event in the fossil record that allowed the scientists compare ancient birds to birds living today. . The team published the results in the journal Scientists progress.
The fossil is a new specimen of a bird named Ichthyornis, who became extinct along with other non-avian dinosaurs and lived in what is now Kansas during the late Cretaceous Period. Ichthyornis has a mix of avian and non-avian dinosaur characteristics, including jaws full of teeth but with a beak.
“Living birds have more complex brains than any known animal except mammals,” said lead researcher Christopher Torres, who led the research at UT College of Natural Sciences.
The intact skull allowed Torres and his collaborators to take a closer look at the brain. “This new fossil finally allows us to test the idea that these brains played a major role in their survival,” added Torres, who is now an associate researcher at UT Jackson School of Geosciences.
Bird skulls wrap tightly around their brains. With CT imaging data, the researchers used the skull of Ichthyornis like a mold to create a 3D replica of his brain called an endocast. They compared this endocast with those created for living birds and more distant dinosaur relatives.
The researchers found that the brain of Ichthyornis had more in common with non-avian dinosaurs than living birds. In particular, the cerebral hemispheres, where higher cognitive functions such as speech, thought, and emotions occur in humans, are much larger in living birds than in Ichthyornis. This diagram suggests that these functions could be linked to survival to mass extinction.
“If a feature of the brain affected survival, we would expect it to be present in survivors but absent in victims like Ichthyornis“Torres said.” That’s exactly what we see here. “
“Ichthyornis is the key to unraveling this mystery, ”said Julia Clarke, professor at UT Jackson School of Geosciences and co-author of the study. This fossil helps us get much closer to answering some lingering questions about living birds and their survival among dinosaurs.
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The above article was posted from a wireframe source with minimal title and text edits.
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