Open Paleo

Ulughbegsaurus

Tanaka et al., 2021 Disputed

Named after Ulugh Beg (the 15th-century Timurid sultan and astronomer), combined with Greek sauros meaning 'lizard'; translates as 'Ulugh Beg's lizard'

93.9–89.8 million years ago Turonian, Late Cretaceous
Late Cretaceous stages

Ulughbegsaurus is an extinct genus of carcharodontosaurid theropod dinosaurs from the Late Cretaceous Bissekty Formation (Turonian age) and Khodzhakul Formation (Cenomanian age) of Uzbekistan. The genus contains a single species, Ulughbegsaurus uzbekistanensis, known from multiple maxilla fragments.

Under dispute

Ulughbegsaurus uzbekistanensis was described as a carcharodontosaurian close to Neovenator (Tanaka and colleagues, 2021), but its identity has been questioned, with some workers treating the material as indeterminate or non-carcharodontosaurian (Sues and colleagues, 2023; Kellermann and colleagues, 2025). It is placed conservatively at Carcharodontosauria incertae sedis.

Diagnosis

  1. Series of shallow, oval depressions on the lateral surface along the ventral edge of maxilla
  2. Tubercles along with ridged rim of the antorbital fossa
  3. Vertically oriented ridges on the lateral surface of maxilla
  4. Large foramina at dorsal edge of dental plates in maxilla
  5. Rugose lateral surface texture characteristic of Carcharodontosauria

Species

Ulughbegsaurus uzbekistanensis Tanaka et al., 2021 Disputed

Type species

Named for Uzbekistan, the country where the fossils were discovered.

Holotype
UzSGM 11-01-02 , State Geological Museum of Uzbekistan
Material
Partial maxilla with teeth
Horizon
Bissekty Formation, Turonian, Late Cretaceous , 93.9–89.8 million years ago
Locality
Dzharakuduk, Navoiy, Uzbekistan

Notable specimens

  • ZIN PH 2368/16

    Zoological Institute, Russian Academy of Sciences range extension

    A right maxilla fragment referred to Ulughbegsaurus sp. from the older early Cenomanian Khodzhakul Formation, extending the genus into an earlier formation than the Turonian Bissekty holotype.

    Averianov et al. (2025)

References

  1. Averianov, A. O.; Kuzmin, I. T.; Skutschas, P. P.; Sues, H. D. (2025). First record of Carcharodontosauridae (Dinosauria, Theropoda) in the Upper Cretaceous Khodzhakul Formation of Uzbekistan. Journal of Paleontology 1-13. doi:10.1017/jpa.2025.1 averianov2025c
  2. Tanaka, K.; Anvarov, O. U. O.; Zelenitsky, D. K.; Ahmedshaev, A. S.; 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). The Royal Society. doi:10.1098/rsos.210923 tanaka2021a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026c
  4. Kellermann, M.; Cuesta, E.; Rauhut, O. W. M. (2025). Re-evaluation of the Bahariya Formation carcharodontosaurid (Dinosauria: Theropoda) and its implications for allosauroid phylogeny. PLOS ONE 20(1): e0311096. Public Library of Science (PLoS). doi:10.1371/journal.pone.0311096

    Re-evaluation of Bahariya carcharodontosaurid material bears on Ulughbegsaurus's carcharodontosaurid affinities.

    kellermann2025a
  5. Sues, H. D.; Averianov, A.; Britt, B. B. (2023). A giant dromaeosaurid theropod from the Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan and the status of Ulughbegsaurus uzbekistanensis. Geological Magazine 160(2): 355-360. Cambridge University Press (CUP). doi:10.1017/S0016756822000954

    Questioned the Ulughbegsaurus material as indeterminate or non-carcharodontosaurian.

    sues2023a