Krzyzanowskisaurus, a New Name for a Probable Ornithischian Dinosaur from the Upper Triassic Chinle Group, Arizona and New Mexico, Usa

Recent discoveries have demonstrated that Revueltosaurus callenderi Hunt is not an ornithischian dinosaur, so it is probably not congeneric with the putative ornithischian Revueltosaurus hunti Heckert. Revueltosaurus Hunt, 1989 is the senior generic name, so I propose here the generic name Krzyzanowskisaurus for “Revueltosaurus” hunti. Because the teeth of K. hunti appear more derived than R. callenderi, and are in fact more “typically” ornithischian than those of R. callenderi, I tentatively suggest that it does in fact represent an ornithischian dinosaur. Both R. callenderi and K. hunti have biostratigraphic significance. The former is an index taxon of the Revueltian land-vertebrate faunachron (lvf), and the latter is an index taxon of the Adamanian lvf. Indeed, the stratigraphic range of R. callenderi discriminates a discrete interval of Revueltian time (Barrancan) and that of K. hunt a subset of Adamanian time (St. Johnsian).