The Collaborative International Dictionary of English v.0.48:

Katsuwonus \Katsuwonus\ prop. n.
   A genus of oceanic bonitos; in some classifications it is
   placed in its own family Katsuwonidae.

   Syn: genus Katsuwonus.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Katsuwonus
    n 1: oceanic bonitos; in some classifications placed in its own
         family Katsuwonidae [syn: Katsuwonus, genus Katsuwonus]