Archaeornithomimus

Archaeornithomimus was an early ornithomimid theropod that lived during the earlier part of the Late Cretaceous in what is now Inner Mongolia, China. Discovered during the Central Asiatic Expeditions led by the American Museum of Natural History, its fossils include disarticulated remains of limbs, feet, and pelvic bones. Reaching approximately three metres in length, it was somewhat smaller and more robust in certain foot proportions than its later relatives such as Gallimimus and Ornithomimus. Its foot structure indicates that it was already well adapted for fast running across open terrain, although it lacked some of the extreme cursorial specialisations of later species. While toothless jaws have not been fully preserved, its close evolutionary relationships indicate that it was an omnivore or herbivore that fed on soft plant tissues, fruits, and small animals across the lake margins and floodplains of the Iren Dabasu Formation.

It represents one of the earliest recognised members of the derived ornithomimid family in Asia.

Where and when

Archaeornithomimus lived in the Late Cretaceous, from 96 to 89 million years ago (Cenomanian-Turonian age). Its remains come from China, in the Iren Dabasu Formation.

The numbers

Length 3.3 m (estimates run from 3 to 3.5 m). Mass about 67 kg. Hip height about 1.2 m. That is 1.9 human-lengths, or 0.29 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, first ma, last ma, hip height.

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