Kiyacursor

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Kiyacursor
Temporal range: Early Cretaceous, Aptian
Kiyacursor.jpg
Holotype specimen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Noasauridae
Genus: Kiyacursor
Averianov et al., 2024
Species:
K. longipes
Binomial name
Kiyacursor longipes
Averianov et al., 2024

Kiyacursor (meaning "Kiya River runner") is an extinct genus of noasaurid theropod dinosaur from the Early Cretaceous Ilek Formation of Russia. The genus contains a single species, K. longipes, known from a partial skeleton. Kiyacursor represents the first Early Cretaceous ceratosaur discovered in Asia, as well as the second non-avian theropod named from Russia, after Kileskus in 2010.

Contents

Discovery and naming

Life restoration Kiyacursor PM-2.png
Life restoration

The Kiyacursor holotype specimen, KOKM 5542, was discovered in the summer of 2023 in sediments of the Ilek Formation (Shestakovo 1 locality) by the Kiya River in Kemerovo Oblast, Russia. [1] The specimen consists of an incomplete skeleton, including cervical and caudal vertebrae, cervical and dorsal ribs, a left scapulocoracoid, humeri, and much of both articulated hind limbs. [2]

A partial cervical vertebra, PIN 329/16, was first described in 2023 by Averianov & Lopatin as belonging to a long-necked theropod similar to basal therizinosauroids like Falcarius . [3] Since this specimen was found in the same locality as the Kiyacursor holotype, Averianov et al. (2024) suggested that the vertebra may represent the same individual as KOKM 5542. [2]

In early 2024, the name "Kiyacursor" (alternatively spelled "Kyacursor") was first mentioned in online sources, including press and social media, but remained a nomen nudum as the peer-reviewed description had not yet been published. [1]

Later that year, Averianov and colleagues formally described Kiyacursor longipes as a new genus and species of noasaurid theropod based on these fossil remains. The generic name, Kiyacursor, combines a reference to the Kiya River near the type locality with the Latin word "cursor", meaning "runner". The specific name, longipes, combines the Latin words "longus", meaning "long", and "pes", meaning "foot". [2]

Description

Size of Kiyacursor compared to a human Kiyacursor Size Comparison.svg
Size of Kiyacursor compared to a human

Averianov et al. (2024) estimated the body length of Kiyacursor at 2.5 metres (8.2 ft). Based on paleohistological studies, they suggested that the holotype individual was an immature subadult when it died, having lived for three years or more. As such, it would have been larger as an adult. [2]

The third metatarsal of Kiyacursor is large, and the second metatarsal is significantly reduced. A similar morphology is observed in the related Elaphrosaurus and Limusaurus , as well as the extant ostrich. This suggests that Kiyacursor likely possessed notable cursorial abilities, being capable of running at high speeds. [2]

Classification

In the strict consensus tree of their phylogenetic analyses, Averianov et al. (2024) recovered Kiyacursor in a clade of basal noasaurids along with Afromimus and an unnamed specimen from the Eumeralla Formation of Australia, [4] which, in turn, is the sister taxon to the clade formed by the Noasaurinae and Elaphrosaurinae. These results are displayed in the cladogram below: [2]

Abelisauroidea

Paleoecology

Kiyacursor was found in outcrops of the Ilek Formation, which dates to the Aptian age of the Early Cretaceous. Other non-avian dinosaurs named from the formation include the early ceratopsian Psittacosaurus sibiricus and the somphospondylan sauropod Sibirotitan . [5] [6] Remains of birds ( Evgenavis and Mystiornis ) [7] [8] and indeterminate dinosaurs (including theropods, sauropods, and stegosaurs) have also been discovered. [9] Fossil pterosaurs, crocodylomorphs, turtles, lizards, various synapsids (including mammaliaforms), and amphibians are also known from the formation. [10] Many of these animals represent relict populations of groups otherwise known from the Jurassic, suggesting that this area of Siberia was a refugium for them. [2] [11] [12]

Related Research Articles

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Huanghetitan, is a genus of sauropod dinosaur from the early Cretaceous Period. It was a basal titanosauriform which lived in what is now Gansu, China.

<span class="mw-page-title-main">Noasauridae</span> Extinct family of dinosaurs

Noasauridae is an extinct family of theropod dinosaurs belonging to the group Ceratosauria. They were closely related to the short-armed abelisaurids, although most noasaurids had much more traditional body types generally similar to other theropods. Their heads, on the other hand, had unusual adaptations depending on the subfamily. 'Traditional' noasaurids, sometimes grouped in the subfamily Noasaurinae, had sharp teeth which splayed outwards from a downturned lower jaw.

<span class="mw-page-title-main">Mamenchisauridae</span> Extinct family of dinosaurs

Mamenchisauridae is a family of sauropod dinosaurs belonging to Eusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Some members of the group reached gigantic sizes, amongst the largest of all sauropods.

Kyasuchus is an extinct genus of shartegosuchid crocodyliform. Fossils have been found from the Ilek Formation outcropping in the Kemerovo Oblast of Russia, deposited during the Aptian and Albian stages of the Early Cretaceous. The localities from which specimens of this genus have been found have also yielded many other vertebrate remains such as those of palaeonisciform fishes, turtles, various lizards, troodontids, triconodonts, the ceratopsian Psittacosaurus, and the protosuchian-grade crocodylomorph Tagarosuchus.

The Murtoi Formation is a geologic formation in vicinity of Lake Gusinoye in Russia. It was deposited in the late Barremian to the mid Aptian of the Early Cretaceous.

The Itat Formation is a geologic formation in western Siberia. It was deposited in the Bajocian to Bathonian ages of the Middle Jurassic. Dinosaur remains are among the fossils that have been recovered from the formation, including the proceratosaurid Kileskus, as well as fish, amphibians, mammals and many other vertebrates. The formation is noted for bearing significant coal reserves, with large open pit coal mines extracting lignite from the unit currently in operation.

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Tagarosuchus is an extinct genus of Early Cretaceous protosuchian-grade crocodyliform. Fossils of Tagarosuchus have been found from southern Siberia, including a nearly complete skull found near the village of Shestakovo in Kemerovo Oblast. Tagarosuchus was named in 1999, with the type species being T. kulemzini. Remains have been recovered from the Aptian-Albian Ilek Formation.

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Xenocretosuchus is an extinct genus of tritylodont therapsids from the Aptian Ilek Formation of Siberia, in the Russian Federation. The type species, X. sibiricus, is known only from dental elements, as is X. kolossovi, described from the Batylykh Formation in 2008. Some authors have treated these species as part of the genus Stereognathus, otherwise known from the Middle Jurassic of Britain, but this is rejected by other authors.

<span class="mw-page-title-main">Ilek Formation</span> Geologic formation in Western Siberia, Russia

The Ilek Formation is a Lower Cretaceous geologic formation in Western Siberia. Many different fossils have been recovered from the formation. It overlies the Late Jurassic Tyazhin Formation and underlies the Albian Kiya Formation.

<i>Sibirotitan</i> Extinct genus of reptiles

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<span class="mw-page-title-main">Batylykh Formation</span> Geological formation in Yakutia, Russia

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<i>Kansaignathus</i> Extinct genus of dinosaurs

Kansaignathus is an extinct genus of dromaeosaurid theropod from the Late Cretaceous Yalovach Formation of Tajikistan. The genus contains only one species, the type species, K. sogdianus. The generic name of Kansaignathus comes from near the town of Konsoy where it was discovered and the Greek word "gnathos" meaning "jaw". The specific epithet "sogdianus" is derived from the historical region of Sogdiana, which was an ancient name for the Fergana Valley region where the fossil was discovered. Kansaignathus is known from a single right dentary bone and a few post-cranial bone fragments. It was the first, and so far the only, dinosaur from Tajikistan to be described and named.

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<i>Ondogurvel</i> Genus of alvarezsaurid dinosaur

Ondogurvel is a genus of alvarezsaurid dinosaur from the Late Cretaceous (Campanian) Barun Goyot Formation in southern Mongolia. The type and only species is O. alifanovi, known from a partial skeleton consisting of fragments of two last dorsal vertebrae, three anterior sacral vertebrae, right ilium, left and right pubis and ischium, articulated right tibia, fibula, metatarsals II and IV, and phalanges IV-1 and IV-2, right carpometacarpus, left and right manual phalanx II-1, right femur, left pedal phalanx II-1, and fragments of unidentified phalanges.

References

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