Ornithomimus

Fossil of Ornithomimus

• North America

Ornithomimus was a genus of dinosaur from the group of Ornithomimosauria within the Theropoda. He lived during the Late Cretaceous in what is now North America. Dromiceiomimus is today mostly as same genus.

Features

Ornithomimus had the typical for all Ornithomimidae physique. It was a slimmer dinosaurs, the relatively small head perched on a long neck. He moved exclusively biped continued ( on hind legs ). Its total length was approximately 3 to 4 meters.

The snout was elongated and ended up in a horny beak, teeth were not available. The head was slightly built and partially pneumatized ( ie with air-filled cavities provided ), the eyes were large and sat sideways on the head. The forelimbs were built relatively large, but weak. The hands wore three fingers, ending in blunt claws. A autapomorphy of this kind is that the first metacarpal bone is longer than the other two. The hind legs were long, the lower leg longer than the thigh, which suggests that Ornithomimus was a fast runner. The metatarsal bones were extended, the feet ending in three forward facing toes.

Due to the modified hind legs Ornithomimus is considered fast runner, possibly reaching speeds over 60 km / hr. What he ate with his toothless beak, is not known. Finds of gastroliths in other Ornithomimosauriern could talk for a plant-based diet. Even small invertebrates as prey or an omnivorous diet are conceivable.

Approximately 72 million year old fossils of a young animal and two adult specimens from Alberta show that Ornithomimus had a downy plumage and the elderly in addition to the fore-arms longer springs possessed that gave their forelimbs a bird wing -like appearance. The late development of the long Vorderarmbefiederung suggests that they probably served the display behavior or the eggs of breeding animals offered additional protection.

System

Ornithomimus was the first known representative of the Ornithomimidae and Ornithomimosauria, its fossils have been found in western North America. The first known species was velox Ornithomimus, described by Othniel Charles Marsh in 1890. The remains of this type are poor, far better get the second type, Ornithomimus edmontonicus, 1933 by Charles Mortram Sternberg is described. Some other species are now either as synonyms of these two styles were classified in its own genus, about Archaeornithomimus. The name means Ornithomimus ( " bird mimic " ) and alludes to the similarity with ratites to.

Finds of this genus are from the U.S. states of Colorado, Utah and Wyoming, as well as from the Horseshoe Canyon Formation in the Canadian province of Alberta. The finds are in the Upper Cretaceous ( Maastrichtian ) dated to an age of about 72-66 million years.

In 1972, on the basis of differences in skeletal proportions of multiple individuals into a new genus Dromiceiomimus ( " emu mimic " ) classified and described with brevitertius D. and D. samueli two ways. Subsequent studies with a wider range of fossils could not confirm this separation, the animals are all classified today edmontonicus in the way Ornithomimus.