Zhongyuanus xichuanensis

Provided that Brontornis is actually a phorusrhacid, and not a descendant of some basal Cretaceous gastornid that got lost in Gondwana, Zhongyuanus xichuanensis, of Early Eocene Zhongyuan, Sichuan province, China, is the last and youngest of the gastornids.

Granted, it is known only from a fragment of the tibiotarsus, but, the fragment is similar enough to Gastornis tibiotarsus to assume (if not safely) that the two are closely related.

Here, Z. xichuanensis is compared to the hippopotamus-like pantodont Coryphodon, which was found literally everywhere in Eurasia and North America during the late Paleocene and early Eocene. The genus lasted until the Middle Eocene, in its final strongholds in China and Mongolia.