Photograph of the Ichthyornis new fossil (top) and a transparent, 3D model (bottom), of the skull (bottom in pink). Credit: Christopher Torres/The University of Texas at AustinBirdbrained today means that you forget where your keys and wallet are. It may have been life-saving for millions of years. This may explain why birds are still the only dinosaurs on Earth.The University of Texas at Austin conducted research on a new bird fossil and discovered that it had a unique brain shape. This may explain why living birds' ancestors survived the mass extinction of all other dinosaurs.Christopher Torres, the lead investigator of the study, said that living birds have brains that are more complex than any other animal except for mammals. He conducted the research while completing a Ph.D. at the UT College of Natural Sciences. Torres is now a National Science Foundation postdoctoral fellow in Ohio University and a research associate at UT Jackson School of Geosciences. "This fossil lets us finally test the hypothesis that their brains played an important role in their survival."This fossil is approximately 70 million years old. It has a nearly complete skull. Scientists were able to use this rare fossil to compare it to birds that are still alive today.These findings were published in Science Advances on July 30, 2012.This fossil is a new example of Ichthyornis, a bird that lived in Kansas during the late Cretaceous Period. Ichthyornis has a blend of avian and nonavian dinosaur-like characteristicsincluding jaws full of teeth but tipped with a beak. Torres and his colleagues were able to examine the skull with greater detail thanks to its intact state.Brain shapes were different in the ancestors living birds than those of dinosaurs, including early birds. This suggests that brain differences could have contributed to survival in the mass extinction of all non-avian dinosaurs. Credit: Christopher Torres/The University of Texas at AustinBird skulls are tightly wrapped around their brains. Researchers used CT-imaging data to create an endocast, a 3D model of Ichthyornis' brain. The endocast was compared to ones made for living birds or distant dinosaurian relatives.Researchers found that Ichthyornis' brain had more similarities to nonavian dinosaurs than with living birds. The cerebral hemispheres, which are responsible for higher cognitive functions, such as speech, thought, and emotion, in living birds, were larger than those in Ichthyornis. This suggests that these functions may be linked to the survival of mass extinction.Torres stated, "If a brain feature affected survivorship, then we would expect it be present in survivors but absent from casualties, such as Ichthyornis." "That's exactly the case here."For centuries, paleontologists have struggled to find skulls from early birds or closely related dinosaurs. Bird skeletons can be fragile and are rarely preserved in three dimensions in the fossil record. It is rare to find well-preserved skulls, but that's what scientists need to know how their brains worked in real life.Julia Clarke, a coauthor of the study and a professor at UT Jackson School of Geosciences, said that Ichthyornis was key to unlocking this mystery. "This fossil will help us get closer to answering some of the persistent questions about living birds and their survival among dinosaurs."Continue reading Tiny ancient bird from China shares skull characteristics with Tyrannosaurus RexInformation: Christopher R. Torres and colleagues, Bird neurocranial evolution and body mass development across the end-Cretaceous Mass Extinction: The avian brain form left other dinosaurs behind Science Advances (2021). Information from Science Advances Christopher R. Torres and colleagues, Bird neurocranial evolution and body mass development across the end-Cretaceous Mass Extinction: The avian brain form left other dinosaurs behind (2021). DOI: 10.1126/sciadv.abg7099
