A 120-million-year-old fossil hen present in China may provide some new clues about how landbound dinosaurs advanced into right now’s flying birds. The dove-sized Cratonavis zhui sported a dinosaur-like head atop a physique much like these of right now’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 practically 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 advanced the cellular higher jaw present in trendy birds (SN: 5/2/18).
It’s amongst only a handful of specimens that belong to a just lately recognized group of intermediate birds often called the jinguofortisids, says Luis Chiappe, a paleontologist on the Pure Historical past Museum of Los Angeles County who was not concerned within the research. Its dino-bird mishmash “shouldn’t be surprising.” Most birds found from the Age of Dinosaurs exhibited extra primitive, toothed heads than right now’s birds, he says. However the brand new discover “builds on our understanding of this primitive group of birds which are on the base of the tree of birds.”
Cratonavis additionally had an unusually elongated scapula and hallux, or backward-facing toe. Hardly ever seen in Cretaceous birds, enlarged shoulder blades may need compensated for the hen’s in any other case underwhelming flight mechanics, the researchers say. And that hefty large toe? It bucks the development of shrinking metatarsals seen as birds continued to evolve. Cratonavis may need used this spectacular digit to hunt like right now’s birds of prey, Li’s group says.
Filling these footwear might have been too large of a job for Cratonavis, although. Given its dimension, Chiappe says, the dino-headed hen would have most definitely been a petite hunter, taking down the likes of beetles, grasshoppers and the occasional lizard somewhat than terrorizing the skies.