Huayangosaurus was a quadruped dinosaur from the Middle Jurassic Period, roughly 165 million years ago, that lived in what is now China. It is one of the oldest known dinosaurs and is an important part of our understanding of early dinosaur evolution. It was named after the Huayang Mountains in Sichuan, where it was first discovered. The Huayangosaurus lived about 20 million years before its popular lookalike, the Stegosaurus.

Key Facts

Huayangosaurus pronunciationhoy-YANG-oh-SORE-us
What does Huayangosaurus mean?Huayang lizard
Dinosaur typeArmored
On the menuHerbivorous
Length4.5 meters ( 15  feet)
Height1.6 m ( 5 feet 4 inches )
Weight400 kg  (about 880 lbs)
Life expectancyUnknown
Legs used to get aroundQuadruped
Estimated top speedUnknown
When they livedMid Jurassic era 170-160 million years ago
Where they have been found?China

When & Where

The Huayangosaurus is known for over fifty partial and complete skeletons, making it one of the best-represented dinosaurs from the Middle Jurassic. Its first fossil was discovered in 1951 and described by Chinese paleontologist C.C. Young the following year. Other Huayangosaurus discoveries were then made following the breakthrough of Young. The holotype specimen, recovered in 1966 from Dashanpu Quarry in Sichuan, China, is the most complete Stegosaurid fossil found to date.

Size & Weight

Huayangosaurus was approximately 5 meters (15 feet) long and weighed around 400 kilograms. It had a small head, a long neck, a bulky body, and a long tail. The Huayangosaurus’s back was covered with large plates of bone connected to each other through smaller bones. These plates may have served as protection against predators. The Huayangosaurus also had a row of large spikes running down its back which, ideally, would translate to extra protection. 

Mobility & Diet

The Huayangosaurus was herbivorous and moved on all fours despite its front legs being slightly shorter than its hind legs. Its teeth were adapted for slicing and chopping leaves, and it probably fed on low-lying plants. Even though the Huayangosaurus is constantly compared to the Stegosaurus, it still had its primitive features. Generally, it is thought to have been a peaceful dinosaur. 

Interesting Points

  • Over the years, the Huayangosaurus has been featured in numerous documentaries, television shows, and books about dinosaurs.
  • The Huayangosaurus is closely related to Stegosaurus. Both dinosaurs come from the same genus.
  • It lived during the Bathonian stage all through to the Callovian stage. 
  • It’s the only member of the Stegosauria that had a special feature: a row of horny scales on both sides of its body.

Featured Image Credit: Nobu Tamura, CC BY 3.0, via Wikimedia Commons