''Dromiceiomimus'' is a genus of

ornithomimid Ornithomimidae (meaning "bird-mimics") is a family of theropod dinosaurs which bore a superficial resemblance to modern ostriches. Ornithomimids were fast, omnivorous or herbivorous dinosaurs known mainly from the Late Cretaceous Period of Laura ...

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

from the Late Cretaceous (early

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...

) of

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

, Canada. The type species, ''D. brevitertius'', is considered a synonym of ''

Ornithomimus edmontonicus ''Ornithomimus'' (; "bird mimic") is a genus of ornithomimid dinosaurs from the Late Cretaceous Period of what is now North America. ''Ornithomimus'' was a swift bipedal theropod which fossil evidence indicates was covered in feathers, equipped w ...

'' by some authors, while others consider it a distinct and valid taxon.

Taxonomy

The type species, ''D. brevitertius'' was originally described as a species of ''

Struthiomimus ''Struthiomimus'' (meaning "ostrich mimic", from the Ancient Greek, Greek στρούθειος/''stroutheios'' meaning "of the ostrich" and μῖμος/''mimos'' meaning "mimic" or "imitator") is a genus of Ornithomimidae, ornithomimid dinosaurs ...

'' by William Parks in 1926 on the basis of a partial postcranium, ROM 797, from the

Horseshoe Canyon Formation The Horseshoe Canyon Formation is a stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. It takes its name from Horseshoe Canyon, an area of badlands near Drumheller. The Horseshoe Canyon Formation is part of th ...

of Alberta, Canada. In his review of Canadian ornithomimids, Dale Russell made ''S. brevitertius'' the type species of a new genus, ''Dromiceiomimus'', meaning "

emu The emu () (''Dromaius novaehollandiae'') is the second-tallest living bird after its ratite relative the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus ''Dromaius''. The 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 ''

'' 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 and Russell cast doubt on the validity of ''Dromiceiomimus'' and though keeping it distinct from ''Ornithomimus'' argued that the limb proportions might be insufficient to distinguish ornithomimid taxa from each other. 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'' Sternberg 1933. 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''. In 2018, Ian McDonald and

Philip John Currie Philip John Currie (born March 13, 1949) is a Canadian palaeontologist and museum curator who helped found the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta and is now a professor at the University of Alberta in Edmonton. In the ...

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 to ''Dromiceiomimus'', differed significantly from that of ''Ornithomimus edmontonicus''. They also pointed out that if both species were to be considered synonymous nevertheless, the specific name ''brevitertius'' would have priority.Ian Macdonald & Philip J. Currie, 2018, "Description of a partial ''Dromiceiomimus'' (Dinosauria: Theropoda) skeleton with comments on the validity of the genus", ''Canadian Journal of Earth Sciences''

References

{{Taxonbar, from=Q1144395 Late Cretaceous dinosaurs of North America Fossil taxa described in 1926 Ornithomimids Maastrichtian life Paleontology in Alberta Controversial dinosaur taxa Taxa named by Dale Russell