Wannia

Wannia is an extinct genus of basal phytosaur reptile known from the Late Triassic (late Carnian or early Norian stage) of Texas, southern United States. It contains a single species, Wannia scurriensis, which is known from a single specimen. This species was originally named as a species referred to Paleorhinus and later was considered as a possible junior synonym of Paleorhinus bransoni. However its re-description revealed five autapomorphies, and a phylogenetic position as the most basal known phytosaur, justifying the erection of a new generic name for the species.

Wannia was first described and named by the late Dr. Wann Langston, Jr. in 1949 as a species referable to Paleorhinus, P. scurriensis. An alternative generic name, Wannia, was proposed by Michelle R. Stocker in 2013 creating the new combination Wannia scurriensis. The generic name honors Langston for his extensive work on archosaur palaeontology, and the specific name refers to the Scurry County where the holotype was found. Wannia is known solely from the holotype TTU P-00539, a partial skull preserved in two parts housed at Texas Tech University. TTU P-11422, a partial juvenile skull, had also been referred to "P." scurriensis, however Stocker (2013) found no basis for this referral as the specimens do not share any synapomorphies. The holotype was collected near Lake Alan Henry, 4 km northeast of the town of Camp Springs, from the Camp Springs Formation of the Dockum Group. Previously known as the Camp Springs Conglomerate, this unit probably correlates with the lower member of the Santa Rosa Sandstone in Texas and the Tecololito Member of the Santa Rosa Formation in New Mexico. The age of this unit is not precisely known, it was originally considered to be late Carnian based on correlations with the Opponitzer Limestone of Austria, using the presence of Dolerosaurus, which was previously considered to be a member of Paleorhinus. However, recent zircon radiometric dating suggests that the Santa Rosa Sandstone is equivalent to the Norian-aged Shinarump Member. Furthermore, the Post Quarry which is within the stratigraphically higher Cooper Canyon Formation of the Dockum Group was recently demonstrated to be mid Norian (220–215 Ma). Thus the most probable age for the Camp Springs Formation and the lower member of the Santa Rosa Sandstone is latest Carnian or early Norian.