Bird brain from dinosaur-age reveals roots of bird intelligence
A unique fossil could transform our understanding of how the bird brain and the intelligence of modern birds evolved. This would solve an enduring mystery of evolution.
Researchers have found a well-preserved fossil bird, around the size of a starling, from the Mesozoic era, the time of the dinosaurs. The complete skull has been preserved almost intact, a rarity for fossils of any kinds, particularly birds, and especially one so ancient.
The three-dimensional preservation of the skull allowed the researchers, led by the University of Cambridge and the Natural History Museum of Los Angeles County, to digitally reconstruct the bird brain, belonging to a creature they named Navaornis hestiae. The bird lived in what is now Brazil, 80 million years ago.
The discovery, reported in the journal Nature, could be a “Rosetta Stone” for understanding some of the evolutionary origins of the modern bird brain. The fossil will fill a 70-million-year gap in our understanding of how they evolved, from the earliest known bird-like dinosaur, the 150-million-year-old Archaeopteryx to today.
Navaornis had a larger cerebrum than Archaeopteryx, suggesting more advanced cognitive capabilities than the earliest bird-like dinosaurs. However, most of its brain were less developed. This suggested it hadn’t evolved the complicated flight control mechanisms we see in birds today.
“The brain structure of Navaornis is almost exactly intermediate between Archaeopteryx and modern birds — it was one of these moments in which the missing piece fits absolutely perfectly,” said co-lead author Dr Guillermo Navalón from Cambridge’s Department of Earth Sciences.
The animal is named after William Nava, director of the Museu de Paleontologia de Marília in Brazil’s São Paolo State, who discovered the fossil in 2016 at a site in the neighbouring Presidente Prudente. Tens of millions of years ago, the area was likely a dry region with slow-flowing creeks. This enabled the fossil’s preservation, allowing the team to use advanced micro-CT scanning to reconstruct the bird brain in remarkable detail.
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