Udanoceratops

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Ordo: †Ornithischia
Cladus: †Genasauria
Cladus: †Neornithischia
Cladus: †Cerapoda
Cladus: †Marginocephalia
Subordo: †Ceratopsia
Cladus: †Neoceratopsia

Familia: †Leptoceratopsidae
Genus: †Udanoceratops

Species: U. tschizhovi
Name

Udanoceratops Kurzanov, 1992

Vernacular names
English: Udanoceratops ("Udan horn face")

Udanoceratops (meaning "Udan's horned face") is a genus of large leptoceratopsid dinosaur that lived during the Late Cretaceous period of Mongolia, in what is now the Djadokhta Formation.
Discovery
Fossil localities of Mongolia and the location of Bayan Mandahu; Udanoceratops fossils have been reported from the Udan Sayr (center) and possibly Baga Tariach (right) localities

Udanoceratops was first named and described by Russian paleontologist Sergei Kurzanov in 1992 and the type species is Udanoceratops tschizhovi. The holotype (PIN 3907/11) was collected during the 1980s at the Udan Sayr (also spelled Udyn Sayr or Üüden Sair) locality of the Djadokhta Formation in Ömnögovi Province, dating to the Campanian stage of the Late Cretaceous period. The generic name is derived from the name of the locality in which the holotype was found (Udan Sayr) and Greek ceras/κέρας meaning "horn" and -ops/ωψ meaning "face". Udanoceratops is best known from the holotype specimen, which represents a large individual comprising a large, relatively well-preserved and almost complete skull, and sparse body remains including vertebrae.[1]

In 1993 a large skull ("nearly 1 m long") assigned to Udanoceratops was reported from the nearby Bayan Mandahu Formation by paleontologist Tomasz Jerzykiewicz.[2] However, Polish paleontologist Łukasz Czepiński in 2020 pointed out that there are no referable specimens to Udanoceratops from the Bayan Mandahu collections, and it is most likely that these remains were confused with the concurring (and relatively large) Protoceratops hellenikorhinus.[3]

In 2004 Viktor S. Tereschhenko referred a juvenile specimen (PIN 4046/11) to Udanoceratops aff. tschizhovi, from the Baga Tariach locality in Dornogovi Province, which Tereschhenko attributed to the Djadokhta Formation.[4] Geological analyses carried out across fossiliferous localities of the Gobi Desert published by Mahito Watabe and team in 2010, indicates that this locality instead correlates best with the Maastrichtian-stage Barun Goyot Formation.[5] The assignment of this specimen, however, has varied since then from "Udanoceratops" sp.,[6][7] to ?Udanoceratops sp.[8]
Description
Size comparison to a 1.8 m tall human

Udanoceratops was a large ceratopsian, estimated at to have reached nearly 4 m (13 ft) long with a weight of 700 kg (1,500 lb).[9] It is the largest leptoceratopsid known so far.[10] The skull had a short frill and no horns over the eyes or nose. Its skull was about 60 cm (600 mm) long. The lower jaw was distinctively robust.[1]
Classification
Reconstruction of the holotype skull

Udanoceratops belonged to the Ceratopsia (the name is derived Greek meaning 'horned face'), a group of herbivorous dinosaurs with parrot-like beaks which thrived in North America and Asia during the Cretaceous Period.[1] It is placed within the Leptoceratopsidae, as the only Asian representative at the time, along with the North American Leptoceratops, Montanoceratops and Prenoceratops.[10]
Paleobiology
Life restoration

Udanoceratops, like all ceratopsians, was a herbivore. The short, deep jaws would have given the animal a powerful bite. The toothless beak would have served to grasp and crop stems or leaves, and as in other leptoceratopsids, the teeth would have met with an action that combined shearing and crushing. The feeding adaptations seen in leptoceratopsids suggest a diet of relatively tough food items, however little is known about the plants that grew in the Gobi Desert during the Cretaceous.[10]
See also

Timeline of ceratopsian research

References

Kurzanov, S. M. (1992). "Новый род протоцератопсид из позднего мела Монголии" [A giant protoceratopsid from the Upper Cretaceous of Mongolia]. Paleontological Journal (in Russian): 81−93.
Jerzykiewicz, T.; Currie, P. J.; Eberth, D. A.; Johnston, P. A.; Koster, E. H.; Zheng, J.-J. (1993). "Djadokhta Formation correlative strata in Chinese Inner Mongolia: an overview of the stratigraphy, sedimentary geology, and paleontology and comparisons with the type locality in the pre-Altai Gobi". Canadian Journal of Earth Sciences. 30 (10): 2180−2195. Bibcode:1993CaJES..30.2180J. doi:10.1139/e93-190.
Czepiński, Ł. (2020). "New protoceratopsid specimens improve the age correlation of the Upper Cretaceous Gobi Desert strata" (PDF). Acta Palaeontologica Polonica. 65 (3): 481−497. doi:10.4202/app.00701.2019.
Tereschhenko, V. S. (2004). "О гетероцельных позвонках у рогатых динозавров (Protoceratopidae, Neoceratopsia)" [On the heterocelous vertebrae in horned dinosaurs (Protoceratopidae, Neoceratopsia)]. Paleontological Journal (2): 81−86.
Watabe, M.; Tsogtbaatar, K.; Suzuki, S.; Saneyoshi, M. (2010). "Geology of dinosaur fossil bearing localities (Jurassic and Cretaceous: Mesozoic) in the Gobi Desert: Results of the HMNS-MPC Joint Paleontological Expedition". Hayashibara Museum of Natural Sciences Research Bulletin. 3: 41–118.
Tereschenko, V. S. (2007). "Key to Protoceratopoid Vertebrae (Ceratopsia, Dinosauria) from Mongolia". Paleontological Journal. 41 (2): 175−188. doi:10.1134/S0031030107020086. S2CID 84954199.
Tereschhenko, V. S. (2008). "Adaptive Features of Protoceratopsids (Ornithischia: Neoceratopsia)". Paleontological Journal. 42 (3): 50−64. doi:10.1134/S003103010803009X. S2CID 84366476.
Kuznetsov, A. N.; Tereschenko, V. S. (2015). "Methods for Size Reconstruction in Distorted and Damaged Vertebrae of Fossil Tetrapods". Paleontological Journal. 49 (3): 293−303. doi:10.1134/S0031030115030120. S2CID 82907196.
Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd ed.). Princeton, New Jersey: Princeton University Press. p. 278. ISBN 9780691167664.
Dodson, P. (1996). The Horned Dinosaurs. Princeton University Press, Princeton, New Jersey. ISBN 0-691-05900-4.