bos primigenius

from WordNet (r) 3.0 (2006)

Bos primigenius
    n 1: large recently extinct long-horned European wild ox;
         considered one of the ancestors of domestic cattle [syn:
         {aurochs}, {urus}, {Bos primigenius}]

from The Collaborative International Dictionary of English v.0.48

Urus \U"rus\, n. [L.; of Teutonic origin. See {Aurochs}.]
   (Zool.)
   A very large, powerful, and savage extinct bovine animal
   ({Bos urus} or {Bos primigenius}) anciently abundant in
   Europe. It appears to have still existed in the time of
   Julius Caesar. It had very large horns, and was hardly
   capable of domestication. Called also, {ur}, {ure}, and
   {tur}.
   [1913 Webster]