Therizinosaur

Therizinosaurs The name therizinosaur is derived from the Greek therizo meaning 'to reap' or 'to cut off' and sauros meaning 'lizard'. The older name segnosaur is derived from Latin segnis meaning 'slow' or 'sluggish' and Greek sauros meaning 'lizard'. (or segnosaurs) are  a clade of theropod dinosaurs which appear to be herbivorous. 

Therizinosaur fossils have been found in Cretaceous deposits in Mongolia, the People's Republic of China and Western North America. Various features of the forelimbs, skull and pelvis show they are theropods and maniraptorans, close relatives to birds.

History
Early finds were incomplete, and showed strange anatomy with features typical of theropods, prosauropods and ornithischians. This led some scientists to think that segnosaurs were a late-surviving suborder of primitive dinosaurs.Paul G.S. 1988. Predatory dinosaurs of the world: a complete illustrated guide. New York: Simon and Schuster. p464  

It was not until the mid-1990s, that their true identity as herbivorous descendants of the carnivorous theropods became generally accepted. Alxasaurus was discovered, and had more typical theropod features; and Therizinosaurus was recognized as a member of the segnosaur group. 

The connection between the therizinosaurids and other theropods was made clear when primitive members of the group, such as Beipiaosaurus (1999) and Falcarius (2005) were discovered. The scientists who described Falcarius noted that it seemed to represent an intermediate stage between carnivorous and herbivorous theropods, a sort of "missing link" between predatory maniraptorans and plant-eating therizinosaurs. 

Although they are now classified as theropods, therizinosaurs had skulls similar to those of sauropods and the shape of their teeth and jaws do make it likely that they were herbivores.

 References 

Category:Coelurosaurs