Symbos cavifrons Leidy, 1853

Woodland musk ox(en)



Taxonomy & Nomenclature

Now considered to represent male individuals of the already described Bootherium bombifrons, which was described based upon females (McDonald & Ray, 1989). This has been confirmed via DNA (Bover et al., 2018).


Conservation Status

Invalid (synonym)

Last record: Late Pleistocene



North America


Biology & Ecology










Allen, J. A. 1913. Ontogenetic and other variations in muskoxen, with a systematic review of the muskox group, Recent and extinct. Memoirs American Museum of Natural History 1 (new ser.), pt. IV:101-226, pls 11-18.

Bover, Pere et al. (2018). Molecular resolution to a morphological controversy: The case of North American fossil muskoxen Bootherium and Symbos. Molecular Phylogenetics and Evolution 129: 70-76. [Abstract]

Case, E. C. (1915). On a nearly complete skull Symbos cavifrons Leidy from Michigan. Univ. Mich. Occ. Pap. Mus. Zool. 13: 1-3.

Case, E. C. (1921). Something about the paleontological collections in the University. Mich. Alumnus 27: 292-300.

Hay, O. P. (1923). The Pleistocene of North America and its vertebrated animals from the states east of the Mississippi River and from the Canadian provinces east of longitude 95[D]. Carnegie Institution of Washington Publication 32: 1-532.

Hibbard, C. W. and Hinds, F. J. (1960). A radiocarbon date for a woodland musk ox in Michigan. Pap. Mich. Acad. 45: 103-108.

Holmes, Branden. (2021). What's Lost and What Remains: The Sixth Extinction in 100 Accounts (eBook). Self published.

McDonald, J.N., and Ray, C.E., 1989, The autochthonous North American musk oxen Bootherium, Symbos, Gidleya (Mam-malia: Artiodactyla: Bovidae): Smithsonian Contributions to Paleobiology, v. 66, p. 1–77.

Milligan, Mark and McDonald, H. Gregory. (2017). Shorelines and vertebrate fauna of Pleistocene Lake Bonneville, Utah, Idaho, and Nevada. Geology of the Intermountain West 4: 181-214.

Nelson, M.E., and Madsen J.H., Jr., 1987, A review of Lake Bonneville shoreline faunas (Late Pleistocene) of northern Utah, in Kopp, R.S., and Cohenour, R.E., editors, Cenozoic geology of western Utah—sites for precious metal and hydrocarbon ac-cumulations: Utah Geological Association Publication 16, p. 319–333.

Semken, H. A., Miller, B. B. and Stevens, J. B. (1964). Late Wisconsin woodland musk oxen in association with pollen and invertebrates from Michigan. Jour. Paleon. 38(5): 823-835.

Wilson, Richard Leland. (1967). The Pleistocene vertebrates of Michigan. Papers of the Michigan  Academy of Science, Arts, and Letters 52: 197-234.


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