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

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Proceedings of the Royal Society B
Authors:
Alexander Averianov at Russian Academy of Sciences
Alexander Averianov
Pavel P. Skutschas at St Petersburg University
Pavel P. Skutschas
Andrey Atuchin
Andrey Atuchin
Dmitry A. Slobodin
Dmitry A. Slobodin
Dmitry A. Slobodin
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Abstract

The noasaurid ceratosaur Kiyacursor longipes 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. Kiyacursor shares unique hind limb proportions with Elaphrosaurus and Limusaurus, 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.
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Research
Cite this article: Averianov AO, Skutschas PP,
Atuchin AA, Slobodin DA, Feofanova OA,
Vladimirova ON. 2024 The last ceratosaur of
Asia: a new noasaurid from the Early
Cretaceous Great Siberian Refugium.
Proc. R. Soc. B 291: 20240537.
https://doi.org/10.1098/rspb.2024.0537
Received: 5 March 2024
Accepted: 18 April 2024
Subject Category:
Palaeobiology
Subject Areas:
palaeontology
Keywords:
Dinosauria, Theropoda, Ceratosauria,
Early Cretaceous, Western Siberia, Russia
Author for correspondence:
Alexander O. Averianov
e-mail: dzharakuduk@mail.ru
Electronic supplementary material is available
online at https://doi.org/10.6084/m9.figshare.
c.7218571.
The last ceratosaur of Asia: a new
noasaurid from the Early Cretaceous
Great Siberian Refugium
Alexander O. Averianov
1
, Pavel P. Skutschas
2
, Andrey A. Atuchin
3
,
Dmitry A. Slobodin
4
, Olga A. Feofanova
4
and Olga N. Vladimirova
4
1
Zoological Institute, Russian Academy of Sciences, Universitetskaya nab., 1, Saint Petersburg 199034,
Russian Federation
2
Department of Vertebrate Zoology, Faculty of Biology, Saint Petersburg State University,
Universitetskaya nab., 7–9, Saint Petersburg 199034, Russian Federation
3
4455 Greenview Dr., Calgary, Alberta, Canada T2E 6M1
4
Kuzbass State Museum of Local Lore, Prospekt Sovetskiy 51, Kemerovo 650000, Russian Federation
AOA, 0000-0001-5948-0799; PPS, 0000-0001-8093-2905
The noasaurid ceratosaur Kiyacursor longipes 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. Kiyacursor shares unique hind limb
proportions with Elaphrosaurus and Limusaurus,suggestingimproved
cursorial ability. These taxa show an ostrich-like specialization of the pes,
with a large third metatarsal and greatly reduced second metatarsal. By con-
trast, 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 shartegosu-
chid crocodyliforms, tritylodontid synapsids and docodontan mammaliaforms.
1. Introduction
Ceratosauria is the first major radiation of theropod dinosaurs to have achieved
great taxonomic diversity and wide geographical distribution [1–3]. They were
probably globally distributed in the Late Jurassic, but were displaced from the
northern continents by other theropod groups and underwent secondary
radiation on the Gondwanan landmasses during Cretaceous time, where they
became dominant predators and survived until the end of the Cretaceous.
Abelisauroidea, the most diverse clade of ceratosaurs, is known from the
Cretaceous of Europe where it is probably represented by secondary dispersals
[4], but in Asia ceratosaurs were not known after the Late Jurassic [5]. Here we
report on the first ceratosaur from the Early Cretaceous in Asia, a new noasaurid
taxon from the Aptian Ilek Formation at Shestakovo 1 locality in Western Siberia,
Russia. This taxon is about 40 Myr younger than the previous youngest record of
ceratosaurs in Asia [5]. The new noasaurid was part of an unusual vertebrate
assemblage, dominated by an advanced ceratopsian dinosaur Psittacosaurus
sibiricus [6,7], but also containing groups of tetrapods that have long since gone
extinct in other regions, like stem salamanders, protosuchian and shartegosuchid
crocodyliforms, tritylodontid synapsids and docodontan mammaliaforms [8–10].
2. Systematic palaeontology
Dinosauria Owen, 1842
Saurischia Seeley, 1887
Theropoda Marsh, 1881
Ceratosauria Marsh, 1881
© 2024 The Author(s) Published by the Royal Society. All rights reserved.
... Vertebrate paleontologists currently assert that many relic taxa with Jurassic affinities existed in the Early Cretaceous Great Siberian Refugium (Aptian Shestakovo in Western Siberia, Berriasian-Barremian Teete in Yakutia), suggesting that the transition from the Jurassic to Cretaceous biotas in Western Siberia and Yakutia was smooth (Skutschas et al. 2023;Averianov et al. 2024 and references therein). The numerous Early Cretaceous relic cryophobic taxa in Siberian amber forests suggest that this refugium persisted in the Late Cretaceous. ...
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