Protoalligator

Protoalligator is an extinct genus of alligatoroid from the Paleocene Wanghudun Formation of China. It was first described as a species of Eoalligator in 1982 before being placed in its own genus in 2016. The name, which translates to "first alligator", was meant to carry on the same meaning as that of Eoalligator ("dawn alligator") as the latter was thought to be synonymous with another crocodilian by the team describing it. Recent studies have suggested that Protoalligator was part of an early radiation of alligatoroids endemic to Asia known as orientalosuchins, though not all studies agree with it being placed within this group nor with orientalosuchins being alligatoroids in the first place. Protoalligator is a monotypic genus, containing only the type species: Protoalligator huiningensis.

==History and naming== The remains of Protoalligator huiningensis were first discovered in 1966 by a geological survey team in Huaining County of the Anhui Province, China, specifically in sediments regarded as part of the Upper Wanghudun Formation. They were subsequently described as a species of Eoalligator by Yang Zhongjian (also known as C.C. Young) in 1982 based on the single partial skull found. Young had erected Eoalligator in 1964, though as noted by later researchers was not especially thorough, assigning a plethora of material to the type species Eoalligator chunyii without proper preparation or comparison with the chosen holotype. Similar problems affected Eoalligator huiningensis, who Young had established without explicitly comparing it to E. chunyii of the genus in the diagnosis. This would come to create some issues later, when Yan-Yin Wang, Corwin Sullivan and Jun Liu noted that certain specimen of Eoalligator chunyii shared several features with Asiatosuchus nanlingensis, which Young had named in the same 1964 study. Wang, Sullivan and Liu addressed this issue by publishing a comprehensive revision of the three crocodilians in 2016, concluding that Eoalligator chunyii was a junior synonym of A. nanlingensis. However, the team still found Eoalligator huiningensis to be sufficiently distinct from Young's other taxa and, as a consequence, placed it in a newly formed genus which they named Protoalligator. In 2018 however, further analysis of the bones of A. nanlingensis and Eoalligator did show that the two were separate taxa after all, though Protoalligator nonetheless remained a distinct genus in its own right, supported in part due to the continued hypothesis of one being an alligatoroid and the other being a crocodyloid. Not long after, in 2019, several Asian crocodilians were placed in the newly named clade Orientalosuchina, among them both Protoalligator and Eoalligator. Orientalosuchina, as initially defined, aligned more closely with the placement of Protoalligator among early alligatoroids. Even though this meant that Protoalligator and Eoalligator were once again close relatives rather than falling into entirely different groups of crocodilians, subsequent authors continued following Wang and colleagues in retaining them as two separate taxa distinguished in their anatomy.