Paleontologists from a leading Chinese research consortium have identified the remains of an extinct bird with a skull that resembles dinosaur anatomy. The findings are reported in Nature Ecology and Evolution.
Fossil specimens of Cratonavis zhui were uncovered during excavations in China. Researchers analyzed the fossils with high-resolution computed tomography to reconstruct the skull and overall anatomy. The cranial features show considerable similarity to the skulls of certain dinosaurs, suggesting a unique transitional stage in early avian evolution. Digital modeling revealed that Cratonavis could not move the upper beak independently from the lower part, a trait that sets it apart from modern birds and hints at a distinct feeding and beak function strategy.
The study also notes an unusually long scapula and a pronounced first metatarsal bone in Cratonavis. In contemporary birds the metatarsus is typically shorter, reflecting different locomotive and flight adaptations. The presence of a longer blade in Cratonavis may have helped compensate for other structural limitations during the early evolution of flight.
Placed on the evolutionary timeline, Cratonavis zhui sits between Archeopteryx, which retains more reptilian features, and the crown group Ornithurae, which exhibits many hallmark avian characteristics. The rock layer in which Cratonavis was found is dated to about 120 million years ago, placing this species in a pivotal period of avian diversification.
These discoveries provide new insight into how dinosaurs began to acquire flight-related adaptations and how these changes culminated in the emergence of modern birds. The research highlights the gradual shifts in skeletal design that enabled powered flight and the complex pathway from theropod dinosaurs to avian lineages.