Apparently the musk-ox (Ovibos moschatus) has little or no near relationship to either the oxen or the sheep; and it is not improbable that its affinities are with the Asiatic takin (Budorcas) and the extinct European Criotherium of the Pliocene of Samos.
This, however, is not all, for Mr Osgood points out that a skull discovered many years ago in the vicinity of Fort Gibson, Oklahoma, and then named Ovibos or Bootherium cavifrons, evidently belongs to the same genus.
Possibly the Arctic musk-ox (Ovibos) may be connected with the takin by means of certain extinct ruminants, such as the North American Pleistocene Euceratherium and the European Pliocene Criotherium (see Chamois, Goral, Serow, Rocky Mountain Goat and Takin).