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The taxonomic status of Merychippus insignis Leidy

Published online by Cambridge University Press:  14 July 2015

Robert L. Evander
Robert L. Evander*
Affiliation:
Department of Science and Mathematics, Emanuel County Junior College, Swainsboro, Georgia 30401
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Extract

The genus Merychippus was erected by Leidy (1857), who named as the type species Merychippus insignis. The type specimen of M. insignis is an immature and incomplete maxilla containing a broken dp2 and a dp3. The type comes from the Bijou Hills of South Dakota, probably from the Barstovian (middle Miocene) Fort Randall Formation of South Bijou Hill in Charles Mix County (Skinner and Taylor, 1967), but possibly from the overlying undifferentiated Ogallala Formation, or possibly from North Bijou Hill in Brule County. Despite this enigmatic type, the species M. insignis has frequently been identified in the fossil record, and the genus Merychippus has grown to include all mesodont horses (Stirton, 1940). Conceptually, the taxon Merychippus is considered a horizontal grade rather than a vertical clade (Simpson, 1945, p. 18). As a horizontal concept, the genus Merychippus derived importance as the ancestral group for the many Mio-Pliocene lineages of hypsodont horses. Today, as horse classification is remodeled along cladistic lines, the taxon Merychippus derives importance from its early naming. Several distinctive horse clades extend upward from a middle Miocene radiation (Stirton, 1940; Quinn, 1955). If M. insignis can be placed within one of these clades, then it is likely that the clade will bear the generic nomen Merychippus because of the antiquity of the name.

Type
Taxonomic Note
Information
Journal of Paleontology , Volume 60 , Issue 6 , November 1986 , pp. 1277 - 1280
Copyright
Copyright © The Paleontological Society 

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References

Forsten, A. 1975. The fossil horses of the Texas Gulf Coastal Plain: a revision. Pearce-Sellards Series, 22, 86 p.Google Scholar
Leidy, J. P. 1857. Notices of extinct Vertebrata discovered by Dr. F. V. Hayden, during the expedition to the Sioux country under the command of Lieut. G. K. Warren. Proceedings of the Academy of Natural Sciences, Philadelphia, 8:311–312.Google Scholar
MacFadden, B. J. and Skinner, M. F. 1981. Earliest Holarctic hipparion, Cormohipparion goorisi n. sp. (Mammalia, Equidae), from the Barstovian (medial Miocene) Texas Gulf Coastal Plain. Journal of Paleontology, 55:619–627.Google Scholar
Patton, T. H. and Taylor, B. E. 1971. The Synthetoceratinae (Mammalia, Tylopoda, Protoceratidae). Bulletin of the American Museum of Natural History, 145:119–218.Google Scholar
Quinn, J. H. 1955. Miocene Equidae of the Texas Gulf Coastal Plain. University of Texas, Bureau of Economic Geology, Publication 5516, 102 p.Google Scholar
Simpson, G. G. 1945. The principles of classification and a classification of the mammals. Bulletin of the American Museum of Natural History, 85, 350 p.Google Scholar
Skinner, M. F., Skinner, S. M. and Gooris, R. J. 1977. Stratigraphy and biostratigraphy of late Cenozoic deposits in central Sioux County, western Nebraska. Bulletin of the American Museum of Natural History, 158:263–370.Google Scholar
Skinner, M. F. and Taylor, B. E. 1967. A revision of the geology and paleontology of the Bijou Hills, South Dakota. American Museum Novitates 2300, 53 p.Google Scholar
Stirton, R. A. 1940. Phylogeny of the North American Equidae. University of California Publications, Bulletin of the Department of Geological Sciences, 25:165–198.Google Scholar
Stoll, N. R. et al. 1961. International Code of Zoological Nomenclature. International Trust for Zoological Nomenclature, London, 176 p.Google Scholar