Ornithomimosauria is a superfamily of theropod dinosaurs. The Ornithomimid dinosaurs had diminutive, toothless jaws, which would have been covered, in life, with a horny beak. A sclerotic ring of bony plates protected their large eyes. Their brains were approximately the size of the modern day ostrich. The animal itself bears a strong resemblance to the ostrich, except, of course, for its long arms, which ended with deadly looking claws, and the presence of a long bony tail.
These dinosaurs were swift runners reaching speeds of up to 37 mph (60 kph). Just what they would have used their long arms and deadly claws for is not clear, and there is disagreement as to what this enigmatic creature would have eaten. Ornithomimosaurs from the Hell Creek include Ornithomimus and Struthiomimus. Some of their contemporaries included T. rex, Triceratops, Denversaurus, Pachycephalosaurus, Thescelosaurus and Edmontosaurus.
The skull and skeleton of this ornithomimid probably represent a new taxon. Because this is the first skull from any member of the family Ornithomimosauridae from the Hell Creek Formation, it is impossible to compare it with other specimens. Clearly, however, the skeleton shows some features in the hand and pelvis that separate it from the described Struthiomimus sedens.