Gigantspinosaurus sichuanensis was an early stegosaur that lived during the mid-Jurassic, about 166 million years ago, in what is now southwestern China.
Around 4.5m long (~14’9″), it had relatively small back plates and a pair of enormous shoulder spikes. It’s unclear exactly how the shoulder spines were positioned in life, but based on how they were found articulated in a fairly complete skeleton they seem to have swept sideways and backwards, protecting Gigantspinosaurus’ flanks.
Skin impressions show a mosaic of polygonal scales with scattered “rosettes” made up of larger scales surrounded by a ring of smaller scales, with a rough ridged surface texture that may have reduced light glare – suggesting an overall more matte appearance rather than glossy.
The thigh bones of one specimen are pathological, showing evidence that these dinosaurs sometimes suffered from bone tumors.
References:
- Hao, Baoqiao, et al. “Redescription of Gigantspinosaurus sichuanensis (Dinosauria, Stegosauria) from the Late Jurassic of Sichuan, Southwestern China.” Acta Geologica Sinica‐English Edition 92.2 (2018): 431-441. https://doi.org/10.1111/1755-6724.13535
- Hao, Baoqiao, et al. “Femoral osteopathy in Gigantspinosaurus sichuanensis (Dinosauria: Stegosauria) from the Late Jurassic of Sichuan Basin, Southwestern China.” Historical Biology 32.8 (2020): 1028-1035. https://doi.org/10.1080/08912963.2018.1561673
- Wikipedia contributors. “Gigantspinosaurus” Wikipedia, 04 Aug. 2025, https://en.wikipedia.org/wiki/Gigantspinosaurus
- Xing, Lida, Peng, G.-Z., and Shu, C.-K. “Stegosaurian skin impressions from the Upper Jurassic Shangshaximiao Formation, Zigong, Sichuan, China: A new observation.” Geological Bulletin of China 27.7 (2008): 1049-1053. http://www.xinglida.net/pdf/XING_et_al_2008_Stegosaurian_skin.pdf
- Zhou, Yuxuan, et al. “Zircon geochronology of the new dinosaur fauna in the Middle Jurassic lower Shaximiao Formation in Chongqing, SW China.” Palaeogeography, Palaeoclimatology, Palaeoecology 592 (2022): 110894. https://doi.org/10.1016/j.palaeo.2022.110894