Coelosaurus antiquus Leidy (Leidy, 1865)

Matthew, W. D., & Brown, B., 1922, The family Deinodontidae, with notice of a new genus from the Cretaceous of Alberta., Bulletin of the American Museum of Natural History 56, pp. 365-385 : 373-374

Coelosaurus antiquus Leidy

Types.—(1) A complete tibia. Described and figured by Leidy, 1865, Smithsonian Contrib., 192, p. 100, Pl. iii, fig. 3. (2) Proximal and distal ends of tibia, distal end of lateral metatarsal, median and lateral proximal phalanges, all of one individual. Described and figured by Leidy, ibid., p. 101, Pl. XVII, figs. 6-11. Cope in 1868 referred the second specimen to “ Laelaps, ” under the name of L. macropus. In the light of present knowledge it appears more probable that Leidy’s original reference should be sustained.

Horizon and Locality.—Cretaceous greensands of New Jersey from Burlington and Monmouth Co. respectively.

So far as one can judge from the types, it would appear that this genus is closely allied to Struthiomimus Osborn and Ornithomimus Marsh , and perhaps identical with one or both. The type specimens are hardly less characteristic than the type of Ornithomimus and, if Struthiomimus is to be abandoned, as Gilmore advocates, on the ground that no adequate generic distinctions from Ornithomimus have been shown to exist, it would seem that the logical procedure would be to abandon both genera in favor of Coelosaurus , on the ground that there is no known distinction at all between them. At all events, it would appear that Gilmore’s ornithomimid bones from the Maryland Cretaceous could with somewhat better probability be referred to Leidy’s genus than to the Western Ornithomimus , typically of much later age than the Arundel and later than the Jersey greensands.