The big whale 🐳

Nomenclature
The genus name, Balaenoptera, means winged whale[3] while the species name, musculus, could mean "muscle" or a diminutive form of "mouse", possibly a pun by Carl Linnaeus[4][3] when he named the species in Systema Naturae.[5] One of the first published descriptions of a blue whale comes from Robert Sibbald's Phalainologia Nova,[6] after Sibbald found a stranded whale in the estuary of the Firth of Forth, Scotland, in 1692. The name "blue whale" was derived from the Norwegian "blåhval", coined by Svend Foyn shortly after he had perfected the harpoon gun. The Norwegian scientist G. O. Sars adopted it as the common name in 1874.[7]

Blue whales were referred to as 'Sibbald's rorqual', after Robert Sibbald, who first described the species.[6] Herman Melville called the blue whale "sulphur bottom" in his novel Moby Dick[8] because of the accumulation of diatoms creating a yellowish appearance on their pale underside.[4][9]

Evolution
Balaenopteridae
 
Minke whale

 
 
 
 
B. musculus (blue whale)

 
 
B. borealis (sei whale)

 
 
 
 
Eschrichtius robustus (gray whale)

 
 
 
B. physalus (fin whale)

 
 
Megaptera novaeangliae (humpback whale)

 
 
 
 
 
A phylogenetic tree of six baleen whale species[10]
Blue whales are rorquals in the family Balaenopteridae. A 2018 analysis estimates that the Balaenopteridae family diverged from other families in between 10.48 and 4.98 million years ago during the late Miocene.[10] The earliest discovered anatomically modern blue whale is a partial skull fossil found in southern Italy, dating to the Early Pleistocene, roughly 1.5–1.25 million years ago.[11] The Australian pygmy blue whale diverged during the Last Glacial Maximum. Their more recent divergence has resulted in the subspecies having a relatively low genetic diversity,[12] and New Zealand blue whales have an even lower genetic diversity.[13]

Whole genome sequencing suggests that blue whales are most closely related to sei whales with gray whales as a sister group. This study also found significant gene flow between minke whales and the ancestors of the blue and sei whale. Blue whales also displayed high genetic diversity.