Neimongosaurus

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda > Tetanurae > Avetheropoda > Coelurosauria > Maniraptora > Therizinosauria > Therizinosauroidea > Therizinosauridae

Overview: Known fossil material from this herbivorous theropod includes much of the neck, the shoulders, arm bones, spinal vertebrae, part of the pelvis, most of its legs, most of the tail, and a part of the lower jaw. This makes it fairly well represented as far as therizinosaurs go. The first of these fossils were found in the late 1990’s, in what is today the region of Inner Mongolia, in China. Described in 2001, its generic name refers to where it was discovered. If it were found a decade or more prior, paleontologists would probably be fairly perplexed by Neimongosaurus. Therizinosaurs have been known to science for quite a while in terms of fossil remains, but what the group was has only been determined relatively recently. Neimongosaurus and its relatives belonged to a clade of rather bizarre maniraptoran theropods; herbivores that evolved from carnivorous ancestors.

The general overall appearance of Neimongosaurus was typical for a therizinosaur. It stood with a semi-upright posture, had an oddly shaped pelvis, an enlarged first toe, a long neck, narrow skull, and enormous arms. Each hand sported three sickle-like claws that were useful for pulling down the branches of trees, for digging up tubers, and probably for defense. Being a maniraptoran, there is a good chance that Neimongosaurus would’ve had some form of feathers or proto-feathers. As a member of the family Therizinosauridae, it was one of the more derived therizinosaurs, but quite a bit smaller than some of its relatives – Therizinosaurus in particular grew to be quite enormous. All known Neimongosaurus fossils come from the Iren Dabasu Formation, so it likely lived around ninety-million years ago, in a warm and semi-arid region.