Shenzhousaurus

• China

Shenzhousaurus is a genus of dinosaur from the group of Ornithomimosauria within the Theropoda. He is considered one of the oldest and most primitive members of this group.

Features

Of Shenzhousaurus is yet only a partial skeleton, in which the head was damaged and did not have the lower parts of the legs, and the rear part of the tail parts of the front legs. Like all Ornithomimosauria he is likely to have moved biped ( two-legged ), the hind legs were much longer than the front legs. The forelimbs were built great, but petite - in contrast to later Ornithomimosauriern the metacarpal bone of the thumb was even shorter than the other two. Another primordial feature is that these dinosaurs had teeth in the front part of the lower jaw - the maxilla was edentulous. Around nine small, conical, not serrated teeth were present per half of the jaw. In the stomach region remains of gastroliths (stomach stones) were discovered, which could be an indication that Shenzhousaurus fed on plants. The specimen has a opisthotonos the similar posture. This curved posture of the neck, together with the head and the tail is not due to an agony, but on decomposition processes after death.

Discovery and designation

The fossil remains of Shenzhousaurus were discovered in the Yixian Formation in Liaoning province and first described in 2003. The name is derived from an ancient name for the land of China. Type species and only known species is Shenzhousaurus orientalis. The find is dated to the Early Cretaceous ( Barremian ) at an age of about 130-126 million years. He is together with Kinnareemimus and Pelecanimimus the oldest known representative of the Ornithomimosauria.

System

Shenzhousaurus applies after Pelecanimimus as basalster representatives of Ornithomimosauria and apart from this as a sister taxon of the remaining genera of this group. The primitive features include the dentition (except Pelecanimimus Harpymimus and all other representatives toothless ), which like the others was straight and not bent forward seat leg in the basin and the first metacarpal bone, which is not the same length.