Reidentification of the holotype specimen of Trilophosaurus buettneri Case, 1928 (Archosauromorpha, Trilophosauridae) from the Upper Triassic of Crosby County, Texas, U.S.A.

Abstract

ABSTRACT The Late Triassic archosauromorph Trilophosaurus buettneri is known from many sites in the Dockum Group and Chinle Formation of Texas and Arizona, spanning nearly 10 Ma from the Otischalkian to the Adamanian estimated holochrons. The holotype specimen, UMMP 2338, was described as a small fragment of a lower jaw in 1928 by E.C. Case. However, at the time no other specimens of the taxon were known. The present availability of several nearly complete skulls, mandibles, and postcranial skeletons referred to T. buettneri allows for reexamination of the anatomical context of the holotype. Here, we provide high-resolution photographs and 3D models of UMMP 2338 to justify our reidentification of the holotypic specimen of T. buettneri as an incomplete maxilla, which may have important implications for future work on trilophosaurid archosauromorphs.