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Ornithomimus velox Marsh, 1890 redescribed



Ben Creisler
bcreisler@gmail.com

A new paper:

Leon P. A. M. Claessens & Mark A. Loewen (2015)
A redescription of Ornithomimus velox Marsh, 1890 (Dinosauria, Theropoda).
Journal of Vertebrate Paleontology (advance online publication)
DOI:10.1080/02724634.2015.1034593
http://www.tandfonline.com/doi/full/10.1080/02724634.2015.1034593

The theropod genus and species Ornithomimus velox was erected based on
a partial hind limb recovered from the late Maastrichtian Denver
Formation. A partial manus, which likely belonged to the same
individual, was also recovered and described in the same paper.
Ornithomimus edmontonicus is the only other valid species currently
recognized in the genus. The validity of Ornithomimus velox has been
questioned due to its fragmentary nature and because the diagnostic
features identified when the species was erected are now considered
characteristic for the family. The pes and manus of Ornithomimus velox
were never fully prepared. In the original description, reconstructed
metatarsals were figured, but manual phalanges, although preserved,
were not described. Here we describe and reevaluate Ornithomimus velox
based upon a new preparation of the specimen. Metacarpal proportions
are diagnostic for the genus, with metacarpal I longer than metacarpal
II, which in turn is longer than metacarpal III. The pes and manus of
Ornithomimus velox are smaller than in the type specimen of
Ornithomimus edmontonicus. Ornithomimus velox can be distinguished
from Ornithomimus edmontonicus based on the robusticity of the pes.
Material previously referred to Ornithomimus velox from the
Kaiparowits Formation of Utah is older and morphologically distinct
and does not represent the same species. The morphological disparity
and temporal separation observed in specimens referred to Ornithomimus
edmontonicus suggest that it may represent a species complex. The
redescription and diagnosis of Ornithomimus velox provides a new
framework to investigate ornithomimid systematics.