Shansisuchus

Shansisuchus Temporal range: Middle Triassic
Skull on display at the Paleozoological Museum of China
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Family:	†Erythrosuchidae
Genus:	†Shansisuchus Young, 1964
Type species
†Shansisuchus shansisuchus Young, 1964

Shansisuchus (meaning "Shansi Province crocodile") is an extinct genus of archosauriform reptile belonging to the family Erythrosuchidae that lived during the Middle Triassic in what is now China. The first fossils of Shansisuchus were discovered from the Ermaying Formation of Shansi Province in 1964 by Chinese paleontologist Yang Zhongjian. Like other erythrosuchids, Shansisuchus was a large-bodied carnivore with a large, deep skull.Shansisuchus is unique among early archosauriforms in having a hole in its skull called a subnarial fenestra.

Shansisuchus is a large erythrosuchid distinguished from other members of the group by two characters: a tongue-and-groove articulation between the premaxilla and nasal bones of the skull and the presence of a subnarial fenestra. In Shansisuchus the premaxilla, a bone that makes up the front of the snout, projects backward and fits into a groove in the nasal, a bone that makes up the top of the snout. The subnarial fenestra is present between the external nares (nasal opening) and the antorbital fenestra, a hole in front of the eye socket. It is separated from the antorbital fenestra by a vertical projection of the maxilla bone. A subnarial fenestra is present in a few other more derived archosauriforms such as some dinosaurs and pseudosuchians, but its morphology in Shansisuchus is unique.

Shansisuchus is known from many fossil skeletons representing more than a dozen individuals, making it one of the best known erythrosuchids. However, all but one specimen discovered in 2010 (a complete skull and 14 vertebrae from Jixian County) are disarticulated, meaning that many aspects of its anatomy had been poorly understood before that specimen was described. Most specimens have been found in a fossil locality in Wuxiang County, and others have been found in localities in Ningwu, Yushe, Jingle, and Xing counties. Three species of Shansisuchus have been named: the type species Shansisuchus shansisuchus, which is known from over ten individuals; S. heiyuekouensis, which is known from five individuals; and S. kuyeheensis, which is known from one individual.

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