Alxasaurus Facts
Pronunciation: AL-ex-ah-SORE-us
Name meaning: Alxa Lizard (named after the Alxa Desert region)
| Diet | Herbivore |
| Height | 2m |
| Length | 4m |
| Weight | 400 kg |
| Environment | Land |
| Era | Cretaceous |
| Period | Early Cretaceous |
| Type | Theropod |
| Location | Inner Mongolia, China |
Alxasaurus was a remarkable theropod dinosaur that lived approximately 121 million years ago during the Early Cretaceous period in what is now Inner Mongolia, China. Despite being a theropod—a group traditionally associated with fearsome predators like Tyrannosaurus—Alxasaurus was actually a peaceful plant-eater that had evolved far from its carnivorous ancestors.
This unusual theropod measured about 4 metres in length and stood roughly 2 metres tall at the hip, making it a moderately-sized dinosaur. Alxasaurus belonged to a specialised group called therizinosauroids, which had evolved extraordinary adaptations for processing plant material. It possessed large, curved claws on its hands—not for catching prey, but likely for pulling down branches and stripping vegetation.
The discovery of Alxasaurus in 1988 proved crucial for palaeontologists trying to understand therizinosaur evolution. Five specimens were recovered from the Bayin-Gobi Formation as part of the China-Canada Dinosaur Project. When scientists Dong Zhiming and Dale Russell studied these fossils, they noticed strong similarities to Segnosaurus, another puzzling dinosaur.
Alxasaurus helped solve a major scientific mystery. Before its discovery, therizinosaurs were thought to be late-surviving primitive sauropodomorphs. However, the detailed study of Alxasaurus provided compelling evidence that these bizarre creatures were actually highly evolved theropods that had abandoned meat-eating in favour of a vegetarian lifestyle.
What made Alxasaurus distinctive?
Alxasaurus had large, curved claws on its hands for processing vegetation, a relatively small head compared to typical theropods, and a robust build adapted for herbivory rather than predation. Its teeth were leaf-shaped and suitable for cutting plant material rather than tearing flesh.
Behaviour
Alxasaurus likely spent much of its time foraging for plants, using its large claws to pull down branches and strip leaves. As a herbivorous theropod, it would have moved more slowly than its predatory relatives, focusing on reaching vegetation rather than chasing prey.
Discovery
Alxasaurus was first described by Dong Zhiming and Dale Russell in 1993. The original fossils were discovered at Bayin-Gobi Formation, Inner Mongolia, China.
Alxasaurus FAQ
What did Alxasaurus eat?
Alxasaurus was a herbivore that fed exclusively on plants. Despite belonging to the theropod group, which includes famous predators like T. rex, Alxasaurus had evolved to eat vegetation such as leaves, shoots, and possibly fruits. Its leaf-shaped teeth were perfectly adapted for cutting and processing plant material rather than tearing flesh.
How big was Alxasaurus?
Alxasaurus measured approximately 4 metres in total length and stood about 2 metres tall at the hip. It weighed an estimated 400 kilograms, making it a moderately-sized dinosaur—larger than a horse but much smaller than giant theropods like
Tyrannosaurus rex.
When did Alxasaurus live?
Alxasaurus lived during the
Early Cretaceous period, approximately 121.4 million years ago. This was a time when flowering plants were beginning to diversify, providing new food sources for herbivorous dinosaurs like Alxasaurus.
Where was Alxasaurus found?
Alxasaurus fossils were discovered in the Bayin-Gobi Formation of Inner Mongolia, China. Five specimens were recovered in 1988 as part of the collaborative China-Canada Dinosaur Project, making this one of the more complete early therizinosaur discoveries.
How do you pronounce Alxasaurus?
Alxasaurus is pronounced 'AL-ex-ah-SORE-us'. The name comes from the Alxa Desert region where it was found, combined with the Greek word 'saurus' meaning lizard.
What does Alxasaurus mean?
Alxasaurus means 'Alxa Lizard', named after the Alxa Desert region in Inner Mongolia where the fossils were discovered. The species name 'elesitaiensis' refers to the specific locality where the specimens were found.
How fast could Alxasaurus run?
The running speed of Alxasaurus is not well established, but as a herbivorous theropod with a robust build, it likely moved more slowly than typical predatory theropods. Its body was adapted for reaching and processing vegetation rather than pursuing prey at high speeds.
What type of dinosaur was Alxasaurus?
Alxasaurus was a theropod dinosaur, specifically belonging to the family Therizinosauridae. This makes it particularly interesting because most theropods were carnivores, but Alxasaurus and its relatives had evolved to become plant-eaters with specialised adaptations for herbivory.
Was Alxasaurus related to birds?
Yes, as a theropod dinosaur, Alxasaurus was more closely related to modern birds than to other dinosaur groups. Theropods are the group from which birds evolved, though Alxasaurus itself was not a direct ancestor of birds but rather a specialised herbivorous branch of the theropod family tree.
How many Alxasaurus fossils have been found?
Five specimens of Alxasaurus have been discovered, all from the same formation in Inner Mongolia. These fossils were found together in 1988 and have provided palaeontologists with a relatively good understanding of this dinosaur's anatomy and evolutionary relationships.
