A groundbreaking discovery is shedding light on how modern birds developed their unique brains and intelligence.
Researchers have found an exceptionally well-preserved fossil of a small bird from the Mesozoic Era, offering valuable insights into a 70-million-year gap in bird evolution.
Named Navaornis hestiae, this ancient bird lived around 80 million years ago in what is now Brazil, long before the asteroid impact that ended the reign of dinosaurs.
The fossil, about the size of a starling, includes a complete skull—an extremely rare find for such an ancient bird.
This remarkable preservation allowed scientists to digitally reconstruct the bird’s brain using advanced micro-CT scanning technology.
The research, led by the University of Cambridge and the Natural History Museum of Los Angeles County, was published in the journal Nature.
Navaornis provides a crucial link between the early bird-like dinosaur Archaeopteryx, which lived 150 million years ago, and today’s birds.
Unlike Archaeopteryx, Navaornis had a larger cerebrum, the part of the brain associated with higher cognitive functions, hinting at more advanced thinking abilities.
However, its cerebellum, which controls flight coordination, was not as developed as in modern birds, suggesting it lacked the precision flying skills of today’s species.
“This fossil is like a missing puzzle piece,” said Dr. Guillermo Navalón from Cambridge’s Department of Earth Sciences. “Navaornis sits right in the middle of a crucial period in bird evolution and helps us understand how their brains developed over millions of years.”
Navaornis was discovered in 2016 by William Nava, director of the Museu de Paleontologia de Marília in São Paulo State, Brazil.
The fossil was preserved in incredible detail thanks to the unique conditions of its ancient habitat, which likely included slow-moving creeks. This preservation has allowed researchers to examine the bird’s skull and brain anatomy in extraordinary detail.
Interestingly, Navaornis belonged to a group of early birds called enantiornithines, or “opposite birds,” which were distinct from modern birds but had complex feathers and could likely fly.
However, their brain anatomy raises questions about how they managed flight without the advanced cerebellum seen in living birds.
“This shows that some early birds were already developing complex brain features while retaining primitive traits,” said Dr. Navalón.
The fossil also suggests Navaornis may have used its advanced cognitive abilities for tasks like finding food, seeking shelter, or engaging in social behaviors like mating displays. “It’s fascinating to think about how these birds were navigating their environment during the age of dinosaurs,” said Professor Daniel Field, senior author of the study.
Navaornis is part of a growing collection of significant fossil bird discoveries made by Field’s research team, including Ichthyornis, Asteriornis (nicknamed the “Wonderchicken”), and Janavis. Each of these fossils contributes to our understanding of how birds evolved from dinosaur ancestors into the intelligent, diverse species we see today.
While this discovery is a major breakthrough, the researchers believe there is much more to learn. Future studies may explore how Navaornis interacted with its environment and how its brain evolved over time. The site in Brazil where it was found is likely to yield more important fossils, offering further insights into the evolutionary journey of birds.
“This discovery is just the beginning,” said Professor Field. “With Navaornis, we’ve taken a big step toward solving one of the great mysteries of evolution: how modern birds developed their remarkable intelligence.”
Source: University of Cambridge.
