Blue Whale Killed By A Ship Near Sri Lanka, Indian Ocean

Taxonomy
Blue whales are rorquals (family Balaenopteridae), a family that includes the humpback whale, the fin whale, Bryde's whale, the sei whale and the minke whale. The family Balaenopteridae is believed to have diverged from the other families of the suborder Mysticeti as long ago as the middle Oligocene. It is not known when the members of those families diverged from each other.
The blue whale is usually classified as one of eight species in the genus Balaenoptera; one authority places it in a separate monotypic genus, Sibbaldus, but this is not accepted elsewhere. DNA sequencing analysis indicates that the blue whale is phylogenetically closer to the sei whale (Balaenoptera borealis) and Bryde's whale (Balaenoptera brydei) than to other Balaenoptera species, and closer to the humpback whale (Megaptera) and the gray whale (Eschrichtius) than to the minke whales (Balaenoptera acutorostrata and Balaenoptera bonaerensis). If further research confirms these relationships, it will be necessary to reclassify the rorquals.
There have been at least 11 documented cases of blue/fin hybrid adults in the wild. Arnason and Gullberg describe the genetic distance between a blue and a fin as about the same as that between a human and a gorilla. Researchers working off of Fiji believe they photographed a hybrid humpback/blue whale.