Eoalligator

Eoalligator Temporal range: Early Paleocene, 65.5–59 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	Archosauriformes
Order:	Crocodilia
Superfamily:	Alligatoroidea
Clade:	Globidonta
Clade:	†Orientalosuchina
Genus:	†Eoalligator Young, 1964
Type species
†Eoalligator chunyii Young, 1964

Eoalligator is an extinct genus of alligatoroid crocodilian from Paleocene deposits in China.

Systematics

Eoalligator was originally classified as an extinct relative of alligators. The holotype of E. chunyii, IVPP V2716, is a partial skeleton.^[1] A second nominal species, E. huiningensis, was described in 1982 from Anhui.^[2] A 2016 study of Chinese alligators by Wang et al. found Eoalligator chunyii to be a junior synonym of Asiatosuchus nanlingensis and a basal member of Crocodylidae.^[3] However, a subsequent study by Wu et al. disagreed with the synonymy of "Asiatosuchus" nanlingensis and Eoalligator chunyii, finding them to be distinct based on first-hand studies of the holotypes and cladistic analysis, although they agreed in classifying E. chunyii as a crocodyloid.^[4] In 2016, Wang et al. also found Eoalligator huiningensis to be an alligatoroid distinct from E. chunyii, and thus moved Eoalligator huiningensis to the new genus Protoalligator.^[3]

A 2019 study by Massonne et al. included additional taxa from Southeast Asia and found Eoalligator and Protoalligator to be related and as basal members of Alligatoroidea, as shown in the cladogram below:^[5]

Alligatoroidea	Diplocynodontinae† Globidonta Leidyosuchus† Deinosuchus† Navajosuchus† Ceratosuchus† Stangerochampsa† Brachychampsa sealeyi† Brachychampsa montana† Orientalosuchina† Eoalligator† Jiangxisuchus† Protoalligator† Orientalosuchus† Krabisuchus† Alligatoridae Alligatorinae Caimaninae

References

1. Young, C.-C. (1964). "New fossil crocodiles from China" (PDF). Vertebrata PalAsiatica (in Chinese (China) and English). 8 (2): 189–208.
2. Young CC. 1982. A Cenozoic crocodile from Huaining, Anhui. Selected Works of Yang Zhongjian. China: Academia Sinica. 47-48.
3. Yan-Yin Wang; Corwin Sullivan; Jun Liu (2016). "Taxonomic revision of Eoalligator (Crocodylia, Brevirostres) and the paleogeographic origins of the Chinese alligatoroids". PeerJ. 4: e2356. doi:10.7717/peerj.2356. PMC 5012266. PMID 27635329.
4. Xiao-Chun Wu; Chun Li; Yan-Yin Wang (2017). "Taxonomic reassessment and phylogenetic test of Asiatosuchus nanlingensis Young, 1964 and Eoalligator chunyii Young, 1964". Vertebrata PalAsiatica. 56 (2): 137–146.
5. Tobias Massonne; Davit Vasilyan; Márton Rabi; Madelaine Böhme (2019). "A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis". PeerJ. 7: e7562. doi:10.7717/peerj.7562. PMC 6839522. PMID 31720094.