| Dromiceiomimus | |
|---|---|
 | |
| Skull cast | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | †Ornithomimosauria |
| Family: | †Ornithomimidae |
| Genus: | †Dromiceiomimus Russell, 1972 |
| Species: | †D. brevitertius |
| Binomial name | |
| †Dromiceiomimus brevitertius Russell, 1972 | |
| Synonyms | |
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Dromiceiomimus is a genus ofornithomimidtheropod from the Late Cretaceous (earlyMaastrichtian) ofAlberta, Canada. The type species,D. brevitertius, is considered a synonym ofOrnithomimus edmontonicus by some authors, while others consider it a distinct and valid taxon. It was a small ornithomimid that weighed about 135 kilograms (298 lb).[1]
The type species,D. brevitertius was originally described as a species ofStruthiomimus byWilliam Parks in 1926 on the basis of a partial postcranium,ROM 797, from theHorseshoe Canyon Formation of Alberta, Canada.[2]
In his review of Canadian ornithomimids, Dale Russell madeS. brevitertius the type species of a new genus,Dromiceiomimus, meaning "emu mimic" from the old generic name for the emu,Dromiceius. Russell also synonymizedStruthiomimus ingens withDromiceimimus brevitertius. He renamedOrnithomimus samueli into a secondDromiceiomimus species:Dromiceiomimus samueli.Dromiceiomimus was distinguished fromOrnithomimus 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.[3]
In a 1981 publication, however, Nicholls and Russell cast doubt on the validity ofDromiceiomimus and though keeping it distinct fromOrnithomimus argued that the limb proportions might be insufficient to distinguish ornithomimid taxa from each other.[4] In the second edition of the Dinosauria, Makovicky et al. claimed that there is no statistical support for the distinction ofDromiceiomimus fromOrnithomimus, and synonymized it withOrnithomimus edmontonicus Sternberg 1933.[5]
However, a few authors continued to treatDromiceiomimus as valid, and Longrich (2008, 2014) treated ROM 840 (holotype ofStruthiomimus samueli) as a distinct species of ornithomimid related toOrnithomimus.[6][7][8][9]
In 2018, Ian McDonald andPhilip John Currie rejected the conclusions by Makovicky and colleagues. They showed that the thighbone/shinbone ratio of specimen UALVP 16182, found in 1967 by Richard Fox and referred toDromiceiomimus, differed significantly from that ofOrnithomimus edmontonicus. They also pointed out that if both species were to be considered synonymous nevertheless, the specific namebrevitertius would have priority.[10]
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