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

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.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the author(s).

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are openly available in Morphosource at https://www.morphosource.org/projects/000572022 or are available by contacting the University of Michigan Museum of Paleontology or Petrified Forest National Park.

ACKNOWLEDGMENTS

We thank M. Smith, D. Wagner, D. Boudreau, and P. Varela for preparation of the PEFO specimens and curation support. We thank the many student interns, volunteers, and PEFO staff who assisted in collection efforts at PFV 456. Thanks to C. Sagebiel and M. Brown for access to TMM collections and to N. Volden for access to NMMNH collections. This work utilized data produced in the CTEES facility at the University of Michigan, supported by the Department of Earth and Environmental Sciences and the College of Literature, Science, and the Arts. These data are provided courtesy of the University of Michigan Museum of Paleontology. Rolf Mueller and Jake Socha facilitated μCT scanner access at Virginia Tech; funding to BTK for scanning provided by the National Science Foundation (EAR480383). This is Petrified Forest National Park Contribution no. 95. Views expressed herein are those of the authors and do not represent the views of the United States Government. Funding was provided by Petrified Forest National Park and the University of Michigan Museum of Paleontology. We thank the editors, A. Heckert, and an anonymous reviewer for their constructive reviews.

AUTHOR CONTRIBUTIONS

ADM and BTK designed the project and drafted the manuscript with ANR. BTK, ADM, and WAR collected the PEFO fossils. All authors collected photographic and CT data and edited the manuscript.