Yuanjiawaornis

Yuanjiawaornis is known from a nearly complete skeleton without a skull, found in 2005 by a paleontologist near the village of Yuanjiawa.1

Most enantiornithine birds were as small as sparrows or starlings, but Yuanjiawaornis was much larger, about the size of Zhouornis.12

The fossil of Yuanjiawaornis has no preserved feathers, which is unusual for bird fossils from Liaoning.1

Yuanjiawaornis lived during the Early Cretaceous period, about 120 million years ago, in the Jiufotang Formation.13

The holotype specimen was probably a young adult, because its wrist bones were not fully fused.2

Yuanjiawaornis had a uniquely shaped synsacrum (a fused part of the backbone) that may be special to enantiornithine birds.2