Temporal range: Upper Cretaceous
New, well-preserved finds such as Alxasaurus in 1993 and Beipiaosaurus in 1996 provided details about the bird-like pelvis, feet and skulls of primitive members. This helped confirm they belonged to the same group of theropod dinosaurs as Therizinosaurus and that therizinosaurs were, more specifically, advanced, herbivorous maniraptoran theropods.
Their fossils were first found in the late 1940s in Asia. They were named in 1954 after more bones were found. It was a thought to be a carnivore and herbivore; it had very long claws - they were about 3 ft long.
The feeding habits of Therizinosaurus are unknown, since no skull material has ever been found that could indicate its diet. However, like other therizinosaurs, it was probably primarily herbivorous.
There are multiple possible functions that could have been served by the claws of Therizinosaurus, such as defense against predators (e.g. the contemporary Tarbosaurus) and in intraspecific fighting, such as fighting for territory or for mating, or to pull leafy tree branches towards its mouth. The claws may have served all these functions.
- Svarney T.E. and Svarney P.B. 2003. The handy Dinosaur answer book. 1st ed. Canton, MI: Visible Ink Press.