Discovered in 2016 near the Brazilian municipality of Presidente Prudente, in the state of São Paulo, a bird skeleton belonging to a new species, named Navaorn’s hestia fills a major missing link in bird brain evolution. 80 million years old, it is located “halfway between Archaeopteryx, the oldest bird-like dinosaur that lived on earth 150 million years ago, and modern birds,” marvels New Scientist.
Its exceptional preservation made it possible to reconstruct its brain and thus understand how this organ had evolved. Its description is detailed in the review Nature. The small skull, less than 3 centimeters long, including beak, “was in such good condition that scientists were able to reconstruct a three-dimensional model of the brain” from high-resolution scanner images, explains the British weekly.
Quoted by the Australian site Cosmos, one of the co-authors, Guillermo Navalón, of the University of Cambridge, United Kingdom, says:
“It was one of those moments where all the missing pieces fit perfectly.”
Between the dinosaur and today’s bird
Because if the primitive bird is exactly halfway on the time scale between the avian dinosaurs and the birds of today, “he also represents a perfect intermediary” morphologically, explains the specialist.
More precisely, “Navaornis hestiae had a larger brain than that of Archaeopteryx, suggesting more developed cognitive abilities,” summarizes the site of the BBC.
But its brain did not yet resemble that of a modern bird. “Most brain areas are less developed, suggesting that this bird had not yet acquired the complex mechanisms of flight control,” continues the public media across the Channel. His spatial orientation abilities were also certainly less, given the small size of his cerebellum. Difficulties probably compensated by a vestibular device, located in the inner ear, which is particularly bulky, the researchers imagine.
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