A revised early Jurassic to Albian chronology for dinosaur evolution in tropical Asia

Abstract The Mesozoic deposits of the Khorat Plateau in Thailand have yielded a rich but chronologically unclear record of dinosaur evolution. Here, we use detrital zircon U-Pb dating to establish precise ages for these deposits. The Nam Phong Formation, once thought to include some of the oldest sauropodomorphs, is now dated to the Pliensbachian stage of the Early Jurassic (ca. 190 Ma), at least 20 million years younger than previously assumed. The fauna of the Phu Kradung Formation, known for eusauropods and allosauroids, spans the Kimmeridgian to early Berriasian stages (ca. 155-140 Ma), covering the Late Jurassic to earliest Cretaceous. The diverse Sao Khua Formation dates to the Hauterivian–Barremian stages (ca. 130-120 Ma), while a shift to ornithischian-dominated communities occurs in the Aptian–Albian Khok Kruat Formation (ca. 120-100 Ma). This revised timeline shows that basal sauropodomorphs are significantly younger than assumed. It repositions Thai dinosaur assemblages within the global evolutionary framework, aligning their changes with faunal changes observed elsewhere and filling a critical gap in tropical fossil records. Acknowledgements We thank J. Longerey and J. Dauvier for assistance during zircon extraction at CEREGE, E. Gazquez for the conception of Figs. 1 and 4, and Mr. Sutham Wongchun, Chief of Phu Wiang National Park, as well as the Department of Mineral Resources of Thailand, for allowing sample collection and export. Funding This research was funded by internal grants and is not associated with any external source of funding. Author information Authors and Affiliations Corresponding author Ethics declarations Competing interests The authors declare no competing interests. Additional information Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Rights and permissions Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/. About this article Cite this article Licht, A., Martin, J.E., Chanthasit, P. et al. A revised early Jurassic to Albian chronology for dinosaur evolution in tropical Asia. Commun Earth Environ (2026). https://doi.org/10.1038/s43247-026-04096-5 Received: Accepted: Published: DOI: https://doi.org/10.1038/s43247-026-04096-5