Open Paleo

Suzhousaurus

Li et al., 2007 soo-JOH-SAWR-us

Named after Suzhou (a region in Gansu Province, China) where the fossils were found, combined with Greek sauros, "lizard" — means "Suzhou lizard"

121.4–100.5 million years ago Aptian–Albian, Early Cretaceous
Early Cretaceous stages

Suzhousaurus is an extinct genus of large therizinosaurs from the Early Cretaceous of China. The genus is known from two specimens discovered in the Xiagou and Zhonggou Formations, both part of the Xinminpu Group. These findings were made during fieldwork in 1999 and 2004.

Under dispute

Suzhousaurus is a large therizinosaur whose position relative to Therizinosauridae differs between analyses. Zanno (2010) and Liao and colleagues (2026) recover it as the sister of Therizinosauridae, just outside the family. Kobayashi and colleagues (2022, 2025) recover it in an unresolved polytomy with Therizinosaurus and other derived therizinosaurs, inside the family under either definition, as do Pu and colleagues (2013) and Sues and Averianov (2016). It is placed in Therizinosauroidea.

Diagnosis

  1. Shallow, poorly demarcated glenoid fossa with prominent rounded and striated tumescence on dorsomedial surface of scapular portion
  2. Pubis with strongly concave cranial margin
  3. Large therizinosauroid (humeral proximodistal length 550 mm)

Species

Suzhousaurus megatherioides Li et al., 2007

Type species

From Greek '-oides' meaning 'resembling', indicating a resemblance to the giant ground sloth Megatherium, in reference to the animal's large size and robust build.

Holotype
FRDC-GSJB-99 , The Fossil Research and Development Center of the Third Geology and Mineral Resources Exploration Academy of Gansu Provincial Bureau of Geo-exploration and Mineral Development
Material
Associated partial postcranial skeleton including 10 partial to nearly complete dorsal vertebrae, incomplete dorsal ribs, nearly complete right scapulocoracoid, complete right humerus, left and fragmentary right pubes
Horizon
upper Xiagou Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality
Yujingzi Basin, Gansu, China The holotype is from the gray-variegated beds and a second specimen from the overlying red beds, so sources that list this genus among the Zhonggou fauna are describing the referred material. Li and colleagues (2007) put the type site in white to grey sandy shale.

References

  1. Li, D.; Peng, C.; You, H.; Lamanna, M. C.; Harris, J. D.; Lacovara, K. J.; Zhang, J. (2007). A large therizinosauroid (Dinosauria: Theropoda) from the Early Cretaceous of northwestern China. Acta Geologica Sinica (English Edition) 81(4): 539-549. doi:10.1111/j.1755-6724.2007.tb00977.x li2007a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c
  3. Zanno, L. E. (2010). A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora). Journal of Systematic Palaeontology 8(4): 503-543. doi:10.1080/14772019.2010.488045

    Re-evaluated Therizinosauria, recovering Suzhousaurus just outside Therizinosauridae.

    zanno2010a
  4. Kobayashi, Y.; Takasaki, R.; Fiorillo, A. R.; Chinzorig, T.; Hikida, Y. (2022). New therizinosaurid dinosaur from the marine Osoushinai Formation (Upper Cretaceous, Japan) provides insight for function and evolution of therizinosaur claws. Scientific Reports 12(1). Springer Science and Business Media LLC. doi:10.1038/s41598-022-11063-5

    Recovered Suzhousaurus in a polytomy with Therizinosaurus and other derived therizinosaurs.

    kobayashi2022a
  5. You, H.; Morschhauser, E. M.; Li, D.; Dodson, P. (2018). Introducing the Mazongshan Dinosaur Fauna. Journal of Vertebrate Paleontology 38(sup1): 1-11. Taylor and Francis. doi:10.1080/02724634.2017.1396995

    Places the holotype in the gray-variegated beds of the Yujingzi Basin and correlates those beds with the upper Xiagou Formation.

    you2018a
  6. Suarez, M. B.; Milder, T.; Peng, N.; Suarez, C. A.; You, H.; Li, D.; Dodson, P. (2018). Chemostratigraphy of the Lower Cretaceous dinosaur-bearing Xiagou and Zhonggou formations, Yujingzi Basin, northwest China. Journal of Vertebrate Paleontology 38(sup1): 12-21. doi:10.1080/02724634.2018.1510412

    Characterizes the Zhonggou fauna as including this genus, which reflects the referred red-beds specimen rather than the holotype.

    suarez2018a
  7. Kobayashi, Y.; Zelenitsky, D. K.; Fiorillo, A. R.; Chinzorig, T. (2025). Didactyl therizinosaur with a preserved keratinous claw from the Late Cretaceous of Mongolia. iScience 28(4). Elsevier BV. doi:10.1016/j.isci.2025.112141 kobayashi2025a
  8. Liao, C. C.; Freimuth, W. J.; Zanno, L. E.; Xu, X. (2026). A new therizinosaur from the Early Cretaceous Jehol Biota and ecomorphological patterns among early therizinosaurians. Journal of Systematic Palaeontology 24(2): 2710287. Informa UK Limited. doi:10.1080/14772019.2026.2710287

    Recovered Suzhousaurus as the sister of Therizinosauridae.

    liao2026a
  9. Pu, H.; Kobayashi, Y.; Lü, J.; Xu, L.; Wu, Y.; Chang, H.; Zhang, J.; Jia, S. (2013). An Unusual Basal Therizinosaur Dinosaur with an Ornithischian Dental Arrangement from Northeastern China. PLoS ONE 8(5): e63423. Public Library of Science (PLoS). doi:10.1371/journal.pone.0063423

    Recovered Suzhousaurus within an unresolved Therizinosauridae.

    pu2013a
  10. Sues, H. D.; Averianov, A. (2016). Therizinosauroidea (Dinosauria: Theropoda) from the Upper Cretaceous of Uzbekistan. Cretaceous Research 59: 155-178. doi:10.1016/j.cretres.2015.11.003

    Recovered Suzhousaurus within an unresolved Therizinosauridae.

    sues2016a