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Colodon cf. occidentalisFossil, Fossil Tapir
Dr. Matthew Colbert - The University of Texas at Austin
Colodon cf. occidentalis
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South Dakota School of Mines and Technology Museum of Geology (SDSM 59566 )

Image processing: Dr. Jennifer Olori
Publication Date: 27 May 2005



Excerpted from Colbert, M. W. 2005. The facial skeleton of the early Oligocene Colodon (Perissodactyla, Tapiroidea). Paleontologia Electronica 8:12A:27p


Two skulls of the early Oligocene Colodon from the White River Group in South Dakota are much more derived than previously reported. In particular, morphologies of the facial skeleton and narial region are surprisingly modern, including a deeply retracted nasoincisive incisure, and other indicators of prehensile proboscis development. High resolution X-ray computed tomography (HRXCT) is used to explore the internal anatomy of these tapiroids, and reveals frontal sinuses, and an internal facial skeletal anatomy approaching that of modern tapirs. This not only records an earlier origin for these anatomical conditions than than previously indicated, but in a phylogenetic context indicates that Colodon is more closely related to Tapirus than is Protapirus.

About the Species

This specimen was collected from the Orellan of South Dakota in the 'Metamynodon sandstone,' a channel sand in the lowest Brule Formation located just below the lower nodular layer. The locale is mid-way between Cottonwood Pass and Stronghold Table. The specimen was made available to The University of Texas High-Resolution X-ray CT Facility for scanning by Matthew Colbert of the Department of Geological Sciences, The University of Texas at Austin courtesy of the South Dakota School of Mines, Museum of Geology.

Specimen Photos

Dorsal view

Left-lateral view

Ventral view

About this Specimen

This specimen was scanned by Matthew Colbert on 15 march 2003 along the coronal axis for a total of 576 slices. Each slice is 0.45 mm thick, with an interslice spacing of 0.45 mm and a field of reconstruction of 112 mm.

About the

Colbert, M. W. 1999. Patterns of evolution and variation in the Tapiroidea (Mammalia: Perissodactyla). Ph.D. dissertation, The University of Texas at Austin, Austin, Texas, 464 pp.

Colbert, M. W., and R. M. Schoch. 1998. Tapiroidea and other moropomorphs; pp. 569582 in C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary Mammals of North America. Cambridge University Press, Cambridge, United Kingdom.

Dashzeveg, D., and J. J. Hooker. 1997. New ceratomorph perissodactyls (Mammalia) from the Middle and Late Eocene of Mongolia: their implications for phylogeny and dating. Zoological Journal of the Linnean Society, 120:105138.

Holbrook, L. T. 1999. The phylogeny and classification of tapiromorph perissodactyls (Mammalia). Cladistics, 15:331250.

Radinsky, L. B. 1963. Origin and early evolution of North American Tapiroidea. Bulletin of the Peabody Museum of Natural History, 17:1115.

Radinsky, L. B. 1965a. Evolution of the tapiroid skeleton from Heptodon to Tapirus. Bulletin of the Museum of Comparative Zoology, 134:69103.

Radinsky, L. B. 1965b. Early Tertiary Tapiroidea of Asia. Bulletin of the American Museum of Natural History, 129:183263.

Scott, W. B. 1941. The mammalian fauna of the White River Oligocene. Part V. Perissodactyla. Transactions of the American Philosophical Society, 28:747775.

Schoch, R. M. 1989. A review of the tapiroids; pp. 298320 in D. R. Prothero and R. M. Schoch (eds.), The Evolution of the Perissodactyls. Oxford University Press, New York.

Witmer, L. M., S. D. Sampson, and N. Solounias. 1999. The proboscis of tapirs (Mammalia: Perissodactyla): a case study in novel narial anatomy. Journal of Zoology, 249:249267.


Colbert, M. W. 2005. The facial skeleton of the early Oligocene Colodon (Perissodactyla, Tapiroidea). Paleontologia Electronica 8:12A:27p

& Links

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To cite this page: Dr. Matthew Colbert, 2005, "Colodon cf. occidentalis" (On-line), Digital Morphology. Accessed July 25, 2024 at http://digimorph.org/specimens/Colodon_cf_occidentalis/SDSM/.

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