About Tuojiangosaurus
| Scientific Name (Genus) | Tuojiangosaurus |
| Meaning of Name |
Tuo River lizard
Tuojiang (Tuo River) [Place name] - saurus (lizard) [Greek] |
| Classification | Ornithischia, Thyreophora (Stegosauria, Stegosauridae) |
| Total Length | Approx. 6.5 - 7m |
| Diet | Herbivorous |
| Period | Late Jurassic (approx. 160 million years ago) |
| Sub-classification / Species Name | Tuojiangosaurus multispinus |
| Year of Paper Publication | 1977 |
| Describing Paper |
On the stegosaurian remains from Zigong (Tzekung), Szechuan province.
Vertebrata PalAsiatica 15. by Z. Dong, X. Li, S. Zhou and Y. Zhang. 1977. |
Tuojiangosaurus: Asia's Largest Stegosaur
Tuojiangosaurus is an herbivorous stegosaur representing Asia, discovered in Sichuan Province, China, in 1974. Its total length is estimated to have reached about 6.5 to 7 meters and its weight 2.8 to 4 tons, making it one of the largest Jurassic stegosaurs discovered in Asia.
Because its forelegs were extremely short compared to its hind legs, its entire body leaned forward, positioning its head quite low to the ground. Therefore, it is thought that Tuojiangosaurus fed on low-growing vegetation such as ferns near the surface.
In addition, the premaxilla at the front of its mouth had no teeth and instead formed a horny "beak." It efficiently cropped plants with this beak, and further back in its mouth, it had leaf-shaped teeth lined up for grinding down the food.
This is a mechanism by which multiple animals living in the same area coexist by avoiding unnecessary competition, such as by shifting the types and height of their food or their active times. Tuojiangosaurus flourished by partitioning its niche with other large herbivorous dinosaurs.
Bony Plates on the Back and Powerful Tail Spikes
On the back of Tuojiangosaurus, at least 15 to 17 pairs of bony plates were arranged in two rows from its neck to its hips. Unlike the wide, pentagonal plates of the North American Stegosaurus, the plates of Tuojiangosaurus were characterized by being lower, narrower triangles with sharply pointed tips.
Furthermore, while Stegosaurus had its plates arranged alternately (staggered) along its spine, the plates of this species are thought to have been arranged symmetrically (in parallel). Traces of developed blood vessels are found on the surfaces of these plates, leading to the belief that they were used for thermoregulation or as a display to appeal to mates.
At the end of its tail, sharp bone spikes, a powerful defensive weapon possessed by almost all stegosaurs, protruded in at least two pairs (4 spikes) or four pairs (8 spikes). When a large carnivorous dinosaur like Yangchuanosaurus attacked, it could quickly pivot its body using its short forelegs as an axis and swing this heavy tail around to defend itself.
Were the Shoulder Spikes an Illusion?
Currently, it is thought that shoulder spikes did not exist.
In the past, restorations and skeletal models of Tuojiangosaurus were often depicted with giant spikes protruding from the shoulders (parascapular spines), similar to the African Kentrosaurus. In television programs and encyclopedias, these "shoulder spikes" were treated like a trademark for many years.
However, recent re-examinations revealed a shocking fact. Actually, no fossils corresponding to shoulder spikes were discovered at the Tuojiangosaurus excavation site.
Past restorations were based on the assumption that "because other older stegosaur relatives have spikes, this dinosaur should have them too," or they were mistakenly added from other bone fragments. It has now been concluded that Tuojiangosaurus had no shoulder spikes and its shoulder area was neat and streamlined, much like the North American Stegosaurus.
There was once a debate as to whether the small "Chungkingosaurus," which lived during the same period as Tuojiangosaurus, was actually a "juvenile Tuojiangosaurus." However, based on skeletal features, it is currently considered to be a completely different species (genus).
by Gemini.
Tuojiangosaurus Stamp & Fossil Gallery
