Balaenoptera muscuulus (Linneaus 1758; 30m in length; extant) is the blue whale, the largest animal of all time. A member of the Mysticeti or baleen whales, the blue whale was derived from desmostylians like Behemotops, Paleoparadoxia, anthracobuinds like Janjucetus, hippos like Ocepeia and mesonychids like Mesonyxin descending order.
The jaws lack teeth, which are replaced with baleen, fringed keratin bristles designed to trap krill as the accompanying sea water is pushed out by the huge muscular tongue. Only four fingers are present, as in ancestral taxa.
Toothed whales, like Orcinus, were derived separately from tenrecs, like Leptictidium.