Segnosaurus (Greek for "slow lizard"); pronounced SEG-no-SORE-us
Woodlands of Central Asia
Middle Cretaceous (90 million years ago)
Size and Weight:
About 15-20 feet long and 1,000 pounds
Squat trunk; muscular arms with three-fingered hands
Segnosaurus, scattered bones of which were discovered in Mongolia in 1979, has proven an elusive dinosaur to classify. Most paleontologists lump this species in with Therizinosaurus as a (no surprise here) therizinosaur, based on its long claws and backward-facing pubic bones. It's not even certain what Segnosaurus ate; lately, it has been fashionable to portray this dinosaur as a kind of prehistoric anteater, tearing apart insect nests with its long claws, though it may also have gobbled up fish or small reptiles.
A third possibility for the Segnosaurian diet--plants--would upend established ideas about dinosaur classification. If Segnosaurus and other therizinosaurs were in fact herbivores--and there's some evidence to this effect based on these dinosaurs' jaw and hip structure--they would be the first such theropods of their kind, which would raise many more questions than it answered!