A bird with a T. rex head may help reveal how dinosaurs became birds

A 120-million-year-old fossil hen present in China might provide some new clues about how landbound dinosaurs advanced into in the present day’s flying birds. The dove-sized Cratonavis zhui sported a dinosaur-like head atop a body similar to those of today’s birds, researchers report within the January Nature Ecology & Evolution.

The flattened specimen got here from the Jiufotang Formation, an historic physique of rock in northeastern China that may be a hotbed for preserved feathered dinosaurs and archaic birds. CT scans revealed that Cratonavis had a cranium that was almost an identical (albeit smaller) as these of theropod dinosaurs like Tyrannosaurus rex, paleontologist Li Zhiheng of the Chinese language Academy of Sciences in Beijing and colleagues report. Which means Cratonavis nonetheless hadn’t evolved the mobile upper jaw found in modern birds (SN: 5/2/18).

It’s amongst only a handful of specimens that belong to a not too long ago recognized group of intermediate birds generally known as the jinguofortisids, says Luis Chiappe, a paleontologist on the Pure Historical past Museum of Los Angeles County who was not concerned within the examine. Its dino-bird mishmash “isn’t sudden.” Most birds found from the Age of Dinosaurs exhibited extra primitive, toothed heads than in the present day’s birds, he says. However the brand new discover “builds on our understanding of this primitive group of birds which might be on the base of the tree of birds.”

Cratonavis additionally had an unusually elongated scapula and hallux, or backward-facing toe. Not often seen in Cretaceous birds, enlarged shoulder blades might need compensated for the hen’s in any other case underwhelming flight mechanics, the researchers say. And that hefty massive toe? It bucks the pattern of shrinking metatarsals seen as birds continued to evolve. Cratonavis might need used this spectacular digit to hunt like in the present day’s birds of prey, Li’s group says.

Filling these sneakers might have been too massive of a job for Cratonavis, although. Given its dimension, Chiappe says, the dino-headed hen would have almost definitely been a petite hunter, taking down the likes of beetles, grasshoppers and the occasional lizard slightly than terrorizing the skies.