Late-surviving New Mexican Dinosaurs Illuminate High End-Cretaceous Diversity and Provinciality

Authors

• Andrew G. Flynn, University of New MexicoFollow
• Stephen L. Brusatte, University of Edinburgh
• Alfio Alessandro Chiarenza, University College London
• Jorge García-Girón, University of Oulu
• Adam J. Davis, Baylor University
• C. Will Fenley IV, Baylor University
• Caitlin E. Leslie, Baylor University
• Ross Secord, University of Nebraska-LincolnFollow
• Sarah Shelley, University of Lincoln
• Anne Weil, Oklahoma State University Center for Health Sciences
• Matthew T. Heizler, New Mexico Bureau of Geology and Mineral ResourcesFollow
• Thomas E. Williamson, New Mexico Museum of Natural History and ScienceFollow
• Daniel J. Peppe, Baylor UniversityFollow

ORCID IDs

Flynn https://orcid.org/0000-0002-1371-1878

Brusatte https://orcid.org/0000-0001-7525-7319

Chiarenza https://orcid.org/0000-0001-5525-6730

García-Girón https://orcid.org/0000-0003-0512-3088

Secord https://orcid.org/0000-0003-4400-9608

Shelley https://orcid.org/0000-0001-6628-0226

Weil https://orcid.org/0000-0002-4998-005X

Williamson https://orcid.org/0000-0002-2856-9632

Peppe https://orcid.org/0000-0003-4263-133X

Document Type

Article

Date of this Version

10-23-2025

Citation

Science (2025) 

doi: 10.1126/science.adw3282

Includes supplemental materials

All data that support the findings of this study, including raw paleomagnetic data, are included as supplementary files and are uploaded to the Texas Data Repository (https://dataverse.tdl.org/privateurl.xhtml?token=6544d576-d3fa-4e90-a340-e43a9a75afa1) for permanent archiving prior to publication

Comments

Copyright 2025, the authors. Used by permission

Abstract

It has long been debated whether non-avian dinosaurs went extinct abruptly or gradually at the end-C retaceous (66 million years ago), because their fossil record at this time is mostly limited to northern North America. We constrain a dinosaur-rich unit to the south, the Naashoibito Member in New Mexico, to the very latest Cretaceous (~66.4 to 66.0 million years), preserving some of the last-known non-avian dinosaurs. Ecological modeling shows that North American terrestrial vertebrates maintained high diversity and endemism in the latest Cretaceous and early Paleogene, with bioprovinces shaped by temperature and geography. This counters the notion of a low-diversity cross-continental fauna and suggests that dinosaurs were diverse and partitioned into regionally distinct assemblages during the final few hundred thousand years before the end-C retaceous asteroid impact.