Tuojiangosaurus multispinus

Tuojiangosaurus multispinus was one of the first nearly complete stegosaurs described from China and remains an emblem of the Upper Shaximiao Formation. Its body combined a low head, arched back, robust limbs, alternating plates and a tail armed with spikes. The original reconstruction estimated 17 pairs of dermal armour, although plates and spikes were not preserved in one uninterrupted life position. Consequently, the exact sequence and the placement of isolated long spines shown on museum mounts remain more uncertain than the underlying skeleton.

Its fossils occur between approximately 157 and 154 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The combined holotype and paratype preserve an incompletely known but reconstructable low, narrow skull; much of the vertebral column; both girdles; major limb bones; and numerous dermal plates. Plates were small and rounded near the neck, tall and triangular over the back, then lower and more spike-like toward the pelvis and tail. The mouth carried numerous closely packed leaf-shaped teeth for cropping plants. Forelimbs were shorter than the hind limbs, the pelvis was broad and the tail provided the lever for several long defensive spikes.

• Low, narrow, wedge-shaped skull
• Numerous closely packed leaf-shaped teeth
• Small rounded neck plates grading into tall triangular back plates
• Lower compressed armour toward the pelvis and tail
• Long defensive spikes near the tail tip
• Broad pelvis and hind limbs longer than the forelimbs

Construction work at Wujiaba near Zigong exposed stegosaur remains in 1974. Chinese palaeontologists excavated two partial skeletons from the base of the Upper Shaximiao Formation. Dong Zhiming, Li Xuanmin, Zhou Shiwu and Chang Yijong named Tuojiangosaurus multispinus in 1977, exactly a century after Stegosaurus was named in North America. CV 209 was selected as the holotype and CV 210 as the paratype. Their 1983 monograph expanded the description, combined the incomplete skulls and mapped how different armour shapes may have been distributed along the body.

Discovery credit: Wujiaba construction workers, Zigong field team.

Naming authors: Dong Zhiming, Li Xuanmin, Zhou Shiwu, Chang Yijong.

The Upper Shaximiao Formation preserves river channels, floodplains and lakes within the Sichuan Basin under a warm, seasonally wet climate. Tuojiangosaurus fed among vegetation including conifers, cycads and ferns. The broader dinosaur fauna included sauropods such as Mamenchisaurus, other stegosaurs and large theropods including Yangchuanosaurus, although the formation spans enough time that not every species was a direct contemporary.

The small skull and leaf-shaped teeth indicate a low-browsing herbivore that clipped rather than chewed vegetation extensively. Tail spikes formed the clearest defensive weapon, but fossils do not preserve a swing or an injury directly caused by this species. Plates may have aided display, recognition or heat exchange; their vascularised bone alone cannot choose one function. No trackway, nest or bonebed securely establishes herd size, parental care or mating behaviour for Tuojiangosaurus.

• It was named in 1977, exactly one hundred years after Stegosaurus.
• The genus name refers to the Tuo River system near the discovery site.
• The original monograph reconstructed about 17 pairs of plates and spikes along the body.
• Two incomplete skulls could be combined to reveal a long, low wedge-shaped head.

A research repository is not necessarily a public exhibit. Loan and display status can change, so check with the institution before visiting.

1. 01
   On the stegosaurian remains from Zigong (Tzekung), Szechuan Province

   Dong Zhiming, Li Xuanmin, Zhou Shiwu, Chang Yijong · Vertebrata PalAsiatica 15(4) · 1977

2. 02
   Dinosaurs from the Jurassic of Sichuan

   Dong Zhiming, Zhou Shiwu, Zhang Yihong · Palaeontologia Sinica, New Series C 23 · 1983

   Open source
3. 03
   A review of the Late Jurassic stegosaurs (Dinosauria, Stegosauria) from the People's Republic of China

   Susannah C. R. Maidment, Guangbiao Wei · Swiss Journal of Geosciences 103 · 2010

   Open source
4. 04
   Chongqing Natural History Museum

   Chongqing Municipal People's Government

   Open source
5. 05
   Tuojiangosaurus

   Fukui Prefectural Dinosaur Museum

   Open source