The last ceratosaur of Asia: a new noasaurid from the Early Cretaceous Great Siberian Refugium

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 291; no. 2023; p. 20240537
• Main Authors: Averianov, Alexander O, Skutschas, Pavel P, Atuchin, Andrey A, Slobodin, Dmitry A, Feofanova, Olga A, Vladimirova, Olga N
• Format: Journal Article
• Language: English
• Published: England 15.05.2024
• Subjects: Animals; Biological Evolution; Dinosaurs - anatomy & histology; Dinosaurs - classification; Fossils - anatomy & histology; Siberia; Siberia; Dinosauria; Western Siberia; Early Cretaceous; Ceratosauria; Theropoda; Russia
• ISSN: 1471-2954; 1471-2954
• DOI: 10.1098/rspb.2024.0537

The noasaurid ceratosaur gen. et sp. nov. is described based on a fragmentary skeleton including cervical vertebra, pectoral girdle, humerus and hind limbs from the Lower Cretaceous (Aptian) Ilek Formation at Shestakovo 1 locality in Western Siberia, Russia. This is the first ceratosaur from the Early Cretaceous of Asia, extending the stratigraphic range of Ceratosauria by 40 Myr on that continent. shares unique hind limb proportions with and , suggesting improved cursorial ability. These taxa show an ostrich-like specialization of the pes, with a large third metatarsal and greatly reduced second metatarsal. By contrast, all other fast running non-avian theropod dinosaurs have an arctometatarsalian pes, with the third metatarsal strongly reduced proximally. The new taxon lived in the Early Cretaceous ecosystem containing a number of other Jurassic relics, such as stem salamanders, protosuchian and shartegosuchid crocodyliforms, tritylodontid synapsids and docodontan mammaliaforms.