the world > animals > mammals > order Cetacea (whales) > suborder Mystacoceti > [noun] > family Balaenopteridae > genus Balaenoptera (rorqual) > species musculus (blue whale) (3)
Sibbald's rorqual (see Sibbald, n.).
a bluish-grey rorqual, Balaenoptera musculus, now endangered, which is the largest animal known to have existed; also called Sibbald's rorqual.
Used in the possessive to designate the blue whale, Balænoptera musculus.