Yangchuanosaurus Click to enlarge image
Image: James Reece
© Australian Museum

Fast Facts

  • Classification
    Species
    shangyouensis
    Genus
    Yangchuanosaurus
    Family
    Metriacanthosauridae
    Super Family
    Allosauroidea
    Order
    Avetheropoda
    Phylum
    Chordata
    Kingdom
    Animalia
  • Number of Species
    Two- Y. shangyouensis and Y. zigongensis
  • Size Range
    Up to 8 metres long; weight estimated at 1.44 tons.
  • Feeding Habits
    carnivorous

Introduction

Yangchuanosaurus shangyouensis

Pronounced YAHNG-CHWAHN-oh-SAWR-us
Meaning Lizard from Yang-ch’uan. The species name, shangyouensis, refers to the Shangyou Reservoir Dam, where labourers digging foundations for the Shangyou Reservoir Dam uncovered the first skeleton.
Yangchuanosaurus was a large, upright, fierce carnivore which lived around 160 million years ago as a top predator in China and preyed on other dinosaurs such as Mamenchisaurus.
This large carnivorous dinosaur was an allosaur, not a tyrannosaur.

Identification

Yangchuanosaurus shangyouensis had:

  • dagger-like, curved teeth to help grasp prey;
  • six large holes in the skull to help reduce its weight for better mobility;
  • forward-facing eyes which gave it good depth perception;
  • a long tail to help balance its body when running.

Compared to T. rex, Yangchuanosaurus was smaller and lighter, with longer arms. Like T. rex, it had a large skull, powerful legs.

Habitat

This dinosaurs locality is Shangyou Reservoir, which is in an Oxfordian/Kimmeridgian age terrestrial mudstone in the Shangshaximiao Formation of China.

Distribution

This dinosaur has only been found in Yangchuan county, Sichuan, China.

Feeding and diet

When Yangchuanosaurus roamed, tyrannosaurs were small and relatively primitive. They would have competed with and tried to evade Yangchuanosaurus and their huge blade-like teeth.

Fossils description

Yangchuanosaurus shangyouensis was named after the Shangyou reservoir in Yangchuan county, Sichuan. It was found during the construction of this reservoir in 1979.

The rock formation the fossils were found in have been dated 161–154 million years old (Late Jurassic).
In 1981, these fossils were nearly lost in a flood. Technicians were preparing Yangchuanosaurus at the Chongqing Museum of Natural History, China, when flood waters rose to cover the laboratory floor. And the water kept rising. After many hours, the technicians despaired and prepared to swim, but at last minute the flood began to recede. The technicians – and the Yangchuanosaurus – were saved.

Evolutionary relationships

Yangchuanosaurus shangyouensis was a large theropod or carnosaur. It belonged to the superfamily Allosauridae that occurred worldwide in the Late Jurassic to Early Cretaceous.