Dromiceiomimus

*Dromiceiomimus brevitertius*

**Dromiceiomimus** was an Ornithomimosaur of the late Cretaceous (early Maastrichtian) of Alberta, Canada, 80-65 mya. It had a large brain and large eyes, and long, slender legs.

Founded in the plains of North America, the *Dromiceiomimus* was the fastest dinosaur, running at speeds of up to 40-50 mph. It was an omnivore with a basic diet of insects and vegetation, and occasionally would eat small rodents or lizards. *Dromiceiomimus* means Emu Mimic.

## Taxonomy

The type species, *D. brevitertius* was originally described as a species of *Struthiomimus* by William Parks in 1926 on the basis of a partial postcranium, ROM 797, from the Horseshoe Canyon Formation of Alberta, Canada.

In his review of Canadian ornithomimids, Dale Russell made *S. brevitertius* the type species of a new genus, *Dromiceiomimus*, meaning "Emu mimic" from the old generic name for the emu, *Dromiceius*. Russell also synonymized *Struthiomimus ingens* with *Dromiceimimus brevitertius*. He renamed *Ornithomimus samueli* into a second *Dromiceiomimus* species: *Dromiceiomimus samueli Dromiceiomimus* was distinguished from *Ornithomimus edmontonicus* on the basis of the following characters: humerus shorter than scapula; ulna ~70% of femoral length; preacetabular process, tibia, metatarsus and pedal digit III longer compared to femur.

In a 1981 publication, however, Nicholls an Russell cast doubt on the validity of *Dromiceiomimus* and treated it as synonymous with *Ornithomimus*, arguing that the limb proportions might be insufficient to distinguish it from *Ornithomimus*. In the second edition of the Dinosauria, Makovicky et al. claimed that there is no statistical support for the distinction of *Dromiceiomimus* from *Ornithomimus* and synonymized it with *Ornithomimus edmontonicus*.

However, a few authors continued to treat *Dromiceiomimus* as valid, and Longrich (2008, 2014) treated ROM 840 (holotype of *Struthiomimus samueli*) as a distinct species of ornithomimid related to *Ornithomimus*.

## JPInstitute.com Description

Ornithomimus dinosaurs may have been the fastest of all dinosaurs. They were bipeds that traveled on long, slender legs with three toes. They had large eyes for good sight, small heads with long, thin necks, and toothless beaks. Ornithomimosauria brains were large for their body size. They also had forelimbs with three claws.

Dromiceiomimus appears to have been well suited to its time and ecological niche. It was very fast, had good eyesight, and was smarter than its competitors. These qualities would have aided Dromaeosaurus in evading large predators, locating and catching its prey, and competing with herbivores for food.

Ornithomimosauria have many striking similarities to modern large flightless birds like the Ostrich and Emu. These include legs that were very long in relation to its body, and small heads with large eyes, and a long neck. Since the modern flightless birds can run very fast, it is easy to estimate that Ornithomimosauria could also generate a great deal of speed - possibly over 40 mph!

## Links

https://web.archive.org/web/20040214164251fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_dromi.html#