is a specific kind of: mammal genus.

has as a member: Balaenoptera musculus, blue whale, sulfur bottom | Balaenoptera physalus, common rorqual, fin whale, finback, finback whale | Balaenoptera borealis, sei whale | Balaenoptera acutorostrata, lesser rorqual, minke whale, piked whale.

is a member of: Balaenopteridae, family Balaenopteridae.