Dzharacursor

Dzharacursor Temporal range: Late Cretaceous, upper Turonian PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	† Ornithomimosauria
Family:	† Ornithomimidae
Genus:	† Dzharacursor Averianov & Sues, 2025
Species:	†D. bissektensis
Binomial name
†Dzharacursor bissektensis (Nesov, 1995)

Dzharacursor (meaning "Dzharakuduk runner") is a genus of ornithomimid theropod dinosaurs from the Late Cretaceous (Turonian age) Bissekty Formation of Uzbekistan. The type and only species is Dzharacursor bissektensis, originally assigned to the genus Archaeornithomimus .

Discovery and naming

Speculative life restoration

In 1995, Nesov named a new species of ornithomimosaur from the Bissekty Formation as Archaeornithomimus bissektensis, based on the holotype N 479/12457, a femur of a juvenile individual, along with other referred specimens including the metatarsals. ^[1] However, in subsequent studies, the affinity of A. bissektensis was generally doubted or not mentioned. ^{[2] [3] [4]}

In 2025, Averianov & Sues assigned this taxon to the new genus Dzharacursor. The new generic name combines Dzharakuduk, the name of the locality where its fossils were found, with the Latin word cursor, meaning "runner". They also referred various partial cranial and postcranial materials of several individuals discovered from the same locality for a sufficient diagnosis. These include cranial bones (a premaxilla, frontal, and quadrate), several cervical, dorsal, and caudal vertebrae, sacra, pectoral and pelvic girdles, forelimb bones (humeri, ulnae, metacarpals, phalanges, and unguals), and hindlimb bones (femora, tibiae, fibulae, metatarsals, phalanges, and unguals), most of which were described by Sues & Averianov in 2016. ^{[5] [6]}

Classification

In their phylogenetic analyses, Averianov & Sues (2025) recovered Dzharacursor as a basal member of the Ornithomimidae, more derived than Archaeornithomimus. Their results are displayed in the cladogram below: ^[5]

Ornithomimosauria	Nqwebasaurus Beishanlong Harpymimus Pelecanimimus Shenzhousaurus Tyrannomimus Garudimimus Deinocheirus Ornithomimidae Archaeornithomimus Dzharacursor Sinornithomimus Gallimimus Struthiomimus Anserimimus Ornithomimus edmontonicus

Paleobiology

A femur (ZIN PH 1400/16) referred to Dzharacursor may preserve medullary bone, a type of endosteal bone tissue found in the bones of female birds when preparing to lay eggs. Similar tissues are found in other non-avian dinosaurs and pterosaurs. Based on the size of the individual whose femur was sampled, the presence of this tissue type may indicate that Dzharacursor females reached sexual maturity before somatic maturity. ^[7]

Paleoecology

Dzharacursor coexisted in the Bissekty Formation environment with other theropods, including the carcharodontosaurian Ulughbegsaurus , the tyrannosauroid Timurlengia , and the dromaeosaurid Itemirus . ^[8]

References

1. Nesov, L. A. (1995). "Dinozavri severnoi Yevrazii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii". Institute for Scientific Research on the Earth's Crust. St Petersburg State University: 1–156.
2. Lee, Y.-N.; Barsbold, R.; Currie, P. J.; Kobayashi, Y.; Lee, H.-J.; Godefroit, P.; Escuillié, F.; Chinzorig, T. (2014). "Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus". Nature. 515 (7526): 257–260. Bibcode:2014Natur.515..257L. doi:10.1038/nature13874. PMID   25337880. S2CID   2986017.
3. Watanabe, A.; Gold, M. E. L. G.; Brusatte, S. L.; Benson, R. B. J.; Choiniere, J.; Davidson, A.; Norell, M. A. (2015). "Vertebral Pneumaticity in the Ornithomimosaur Archaeornithomimus (Dinosauria: Theropoda) Revealed by Computed Tomography Imaging and Reappraisal of Axial Pneumaticity in Ornithomimosauria". PLOS ONE. 10 (12): e0145168. Bibcode:2015PLoSO..1045168W. doi: 10.1371/journal.pone.0145168 . PMC   4684312 . PMID   26682888.
4. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ. 7: e7247. doi: 10.7717/peerj.7247 . PMC   6626525 . PMID   31333906.
5. Averianov, A. O.; Sues, H.-D. (2025). "A new ornithomimid theropod from the Upper Cretaceous Bissekty Formation of Uzbekistan". Journal of Vertebrate Paleontology. e2433759. doi:10.1080/02724634.2024.2433759.
6. Sues, Hans-Dieter; Averianov, Alexander (2016-01-01). "Ornithomimidae (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan". Cretaceous Research . 57: 90–110. doi:10.1016/j.cretres.2015.07.012. ISSN   0195-6671.
7. Skutschas, P.P.; Boitsova, E.A.; Averianov, A.O.; Sues, H.-D. (2017). "Ontogenetic changes in long-bone histology of an ornithomimid theropod dinosaur from the Upper Cretaceous Bissekty Formation of Uzbekistan". Historical Biology. 29 (6): 715–729. doi:10.1080/08912963.2016.1233180.
8. Tanaka K, Anvarov OU, Zelenitsky DK, Ahmedshaev AS, Kobayashi Y (2021). "A new carcharodontosaurian theropod dinosaur occupies apex predator niche in the early Late Cretaceous of Uzbekistan". Royal Society Open Science. 8 (9): Article ID 210923. Bibcode:2021RSOS....810923T. doi: 10.1098/rsos.210923 . PMC   8424376 . PMID   34527277.