Tuojiangosaurus

Tuojiangosaurus (meaning "Tuo River lizard") was a type of plant-eating dinosaur that lived a very long time ago during the Late Jurassic Period. It belonged to a group of dinosaurs known as stegosaurians, famous for having bony plates along their backs and spikes on their tails. Fossils of Tuojiangosaurus were discovered in what we now call Sichuan Province in China, in rock layers called the Upper Shaximiao Formation. Studying this dinosaur helps scientists learn more about the amazing creatures that roamed the Earth millions of years ago and how they lived and survived.

Description

Tuojiangosaurus was a large stegosaur that grew to be about 6.5 metres (21 feet) long and weighed around 2.8 metric tons (3.1 short tons). It looked very similar to the North American Stegosaurus, and it is one of the best-known stegosaurs from China.

Tuojiangosaurus had the usual narrow head, strong body, and low teeth that other stegosaurs had. Its legs, especially its front legs, were shorter. It had at least twenty-five teeth in its lower jaw, and these teeth had thick bases. Like Kentrosaurus, Tuojiangosaurus had two rows of plates along its back. These plates became taller near the hips. The plates on the neck and front part of the body were rounded or pear-shaped, while those on the back were more triangular and pointed. Unlike Stegosaurus, the plates of Tuojiangosaurus stood straight up next to each other. Each end of its tail had at least two strong spikes pointing outward at about a 45-degree angle. In stegosaur families, this arrangement of spikes is playfully called the "thagomizer".

Discovery

In 1974, workers building a dam in Zigong, Sichuan, found the bones of a stegosaurian dinosaur.

The dinosaur, named Tuojiangosaurus multispinus, was described in 1977 by scientists Dong Zhiming, Zhou Shiwu, Li Xuanmin, and Chang Yijong. The name comes from the Tuo River, where the dinosaur's bones were found. The fossil, called CV 209, is one of the most complete stegosaurian skeletons found in Asia. It is missing some parts like the skull and tail. A model of this dinosaur can be seen at museums in Chongqing, London, and Beijing.

Classification

Tuojiangosaurus was placed in Stegosauridae in 1977. In 2004, an analysis found it to be closely related to Chialingosaurus. Another study in 2009 was unsure where exactly it fit within the group of stegosaurians because the fossils were not very complete. A later study in 2017 showed that it grouped with Huayangosaurus and its close relatives.

Paleobiology

Tuojiangosaurus was a plant-eater that grazed on low plants and ground vegetation. Some scientists, like Paul, think that two other dinosaurs, Chialingosaurus and Chungkingosaurus, might actually have been young versions of Tuojiangosaurus.