On the other hand, its shoulder girdle was apparently ill-adapted to flapping flight and its furcula was unusual, with a hypocleidum similar to more advanced avialans but a general anatomy even more basal than in Archaeopteryx.

While the tarsometatarsi were more fused than in Archaeopteryx, the fibula was long and reached the distal point of the tarsal joint, not reduced as in more modern birds (and some non-avian theropods like Avimimus).

Not being well-adapted to flapping flight, Sapeornis probably was a glider and/or soarer that preferred more open country compared to the Enantiornithes and predominantly woodland birds, although it was able to perch on branches.

The small gastroliths, overall large size, and the inferred habitat indicate that Sapeornis was most likely a herbivore, possibly eating plant seeds and fruits.

These rocks formed during the late Aptian through early Albian epochs of the Cretaceous period, and are about 125-120 million years old.

It was discovered by a team from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), and was reported in 2002 by the scientists Zhonghe Zhou and Fucheng Zhang.

[8] They chose the name in honor of SAPE, the Society of Avian Paleontology and Evolution, which they combined with the Ancient Greek word όρνις (ornis), meaning "bird".

None of these first three specimens preserved traces of feathers, but based on the size of their skeletons alone, they were recognized as the largest early Cretaceous avialans known at the time.