Shansisuchus

thumb|left|RestorationShansisuchus (meaning "Shanxi 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 Shanxi (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.

==Description== left|thumb|Skull at the Baoding Natural History Museum 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. The vertebrae are very short (with centra that are taller than long), and remarkably, one articulated specimen shows the presence of pretty developed intercentra throughout the entire vertebral column; which, instead of being in-between each vertebra as usual, these were positioned ventrally and wrapped around each articulation of the centra. These adaptations would have reduced flexibility, and made the neck very stiff and strong, likely in support of its relatively large head.