Shunosaurus lii

Brian Franczak

SHUNOSAURUS (SHOE-noh-SORE-us)

Period: Middle Jurassic

Order, Suborder, Family: Saurischia, Sauropodomorpha, Euhelopodidae

Location: Asia (People's Republic of China)

Length: 40 feet (12 meters)

The dominant plant-eater of Middle Jurassic China, Shunosaurus may have roamed in large herds. With its long, thick neck it could feed on plants and leaves high above the ground that most other herbivores could not reach. Its large body, weighing about one ton, made it almost safe from attack by predators, such as the theropod Gasosaurus. The tail of Shunosaurus ended in a large bony club with two pairs of short spikes. It used its tail as a weapon to scare away predators.

Shunosaurus lii, the only species known for the genus, was discovered in 1979 by paleontology students working in the Lower Shaximiao Formation in the Sichuan Province. It was named after the area it was found in; Shuo is a Chinese word that means Sichuan. Since then, more than 20 nearly complete Shunosaurus skeletons, including five good skulls, have been excavated. Shunosaurus is now one of the best-known sauropods.

Shunosaurus was a member of the Euhelopodidae, a diverse family of sauropods that seems to have been geographically restricted to Asia. Although the neck of Shunosaurus was long, it was not as long as the necks of the Late Jurassic sauropods of China and North America. The skull of Shunosaurus shows that it may be near the ancestry of some of the long-necked euhelopodids, such as Mamenchisaurus and Omeisaurus (which may also have had a tail club). It was also related to Datousaurus. As one of the most primitive of the euhelopodids, Shunosaurus may have been close to the ancestry of many different sauropod families, such as the Camarasauridae (with which it shares a short, blunt skull) and the Diplodocidae (with which it shares slender teeth, tall spines on the tail vertebrae, and a few "double beam" chevron bones on the tail).

Dinosaur-bearing Middle Jurassic rocks are rare, so there is a gap in our understanding of dinosaur evolution. To date, the remains of more than 100 dinosaurs have been unearthed from the Dashanpu Quarry. The name "Shunosaurus fauna" is used for that group of Middle Jurassic Chinese animals. Animals of the Shunosaurus fauna have also been found in Tibet and in northern China. These dinosaurs were widespread. Once they are all described, the dinosaurs of the Shunosaurus fauna will help fill in some gaps in our knowledge of dinosaur evolution.