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First record of Carcharodontosauridae (Dinosauria, Theropoda) in the Upper Cretaceous Khodzhakul Formation of Uzbekistan

Published online by Cambridge University Press:  21 April 2025

Alexander O. Averianov Open the ORCID record for Alexander O. Averianov [Opens in a new window] ,
Ivan T. Kuzmin Open the ORCID record for Ivan T. Kuzmin [Opens in a new window] ,
Pavel P. Skutschas Open the ORCID record for Pavel P. Skutschas [Opens in a new window]  and
Hans-Dieter Sues Open the ORCID record for Hans-Dieter Sues [Opens in a new window]
Alexander O. Averianov*
Affiliation:
Zoological Institute, Russian Academy of Sciences, Universitetskaya nab., 1, Saint Petersburg, 199034, Russia
Ivan T. Kuzmin
Affiliation:
Department of Vertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaya nab., 7–9, Saint Petersburg, 199034, Russia
Pavel P. Skutschas
Affiliation:
Department of Vertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaya nab., 7–9, Saint Petersburg, 199034, Russia
Hans-Dieter Sues
Affiliation:
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, MRC 121, P.O. Box 37012, Washington, DC 20013-7012, USA
*
Corresponding author: Alexander O. Averianov; Email: [email protected]
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Abstract

The allosauroid theropod dinosaurs of the clade Carcharodontosauridae were the apex predators in terrestrial ecosystems of the Early Cretaceous but were replaced in this ecological niche by Tyrannnosauridae in the Late Cretaceous. Details of this turnover are poorly known because only two transitional ecosystems, containing both carcharodontosaurids and tyrannosauroids, had been recognized to date (Cenomanian Cedar Mountain Formation of Utah, USA, and Turonian Bissekty Formation of Uzbekistan). Moreover, the presence of carcharodontosaurids in the Bissekty Formation, based on a maxilla fragment identified as Ulughbegsaurus uzbekistanensis Tanaka et al., 2021, has been recently questioned. Here we report on the third ecosystem containing both clades of apex predators, the Cenomanian Khodzhakul Formation in Uzbekistan. This new occurrence of Carcharodontosauridae is based on a newly identified maxilla that closely resembles the holotype maxilla of U. uzbekistanensis and is identified as Ulughbegsaurus sp. The revised morphological characters of both specimens support attribution of Ulughbegsaurus to Carcharodontosauridae. We report a novel neurovascular feature of the theropod maxilla—a medial alveolar canal that supplied the alveoli medially and contained tributaries of the palatine vessels in Ulughbegsaurus.

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Journal of Paleontology , First View , pp. 1 - 13
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Footnotes

Handling Editor: Daniel Ksepka

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