Ovibos moschatus
It’s not often a rare fossil is brought to me by the
general public. Below are photos of a paleoeroded, Late Pleistocene,
partial skull of the Arctic musk ox, Ovibos
moschatus. The species is still alive today, living at high
latitudes of North America. During the last Ice Age (Pleistocene), the
species was much more widely distributed.
Before this skull was found, the fossil record of the
Arctic musk ox in Ohio was only two specimens - one in southwestern Ohio and
one in northeastern Ohio. The skull shown below, currently in private
hands, was found in central Ohio, right in the middle of the species’
previously known paleogeographic distribution.
Locality:
~60 feet below the surface, in clay, from a flooded gravel pit at the St.
Louisville Gravel Pit (Shelley Concrete Company), eastern side of the North
Fork of the Licking River, a little east of Rt. 13, south of St. Louisville,
northern Newton Township, northern Licking County, central Ohio, USA; 40˚ 9.572’ North,
82˚ 24.766’ West.
Age:
late Wisconsinan, 15-18 ky, Late Pleistocene (= age of unconsolidated glacial
sediments at this locality; see Pavey et al., 1999).
Ovibos moschatus - dorsal view of top of skull (anterior at bottom;
posterior at top), ~14.5 cm across at its widest. The protrusion at the
lower left of the photo is the normal bony bulge surrounding the animal's right
eye. Comparison with modern Arctic musk ox
skulls demonstrate that this fossil is a male skull. Male skulls have
long, parallel median margins to the horn attachment pads. Female skulls
have horn attachment pads with median margins that are short and curved.
Ovibos moschatus - ventral view of upper portion of braincase
(anterior at top; posterior at bottom), ~14.5 cm across at its widest.
Ovibos moschatus - anterior view of broken top of skull (dorsal at
top; ventral at bottom), with eroded broken edges, ~14.5 cm across at its
widest. The groove along the dorsal surface marks the boundary between
the two horns (not preserved here). Note the very thick skull top.
Male Arctic musk ox engage in head-butting during mating season. The
thick skull prevents brain damage. The large empty spaces reduce skull
weight, and the interior struts provide strength.
Ovibos moschatus - posterior view of skull (dorsal at top; ventral at
bottom), ~14.5 cm across at its widest. The groove along the dorsal side
marks the boundary between the two horns (not preserved here).
Ovibos moschatus - closeup of braincase (anterior at top; posterior at
bottom), ~8-9 cm across for preserved portion of braincase cavity.
Ovibos moschatus - right lateral view of skull, ~16.5 cm across at its
widest.
Ovibos moschatus - left lateral view of skull, ~16.5 cm across at its
widest.
Species
ID by Dale Gnidovec.
Additional info. synthesized from:
McDonald, H.G. & R.A. Davis. 1989.
Fossil muskoxen of Ohio. Canadian Journal of Zoology 67:
1159-1166.
Hansen, M.C. 1997. Phylum Chordata -
vertebrate fossils. in Fossils of Ohio. Ohio
Division of Geological Survey Bulletin 70: 288-369.
Pavey, R.R., R.P. Goldthwait, C.S. Brockman, D.N.
Hull, E.M. Swinford & R.G. Van Horn. 1999. Quaternary geology
of Ohio. Ohio Division of Geological Survey Map 2.