Rorquals are the largest group of baleen whales, which comprise the family Balaenopteridae, containing ten extant species in three genera. They include the largest animal that has ever lived, the blue whale, which can reach 180 tonnes, and the fin whale, which reaches 120 tonnes ; even the smallest of the group, the northern minke whale, reaches 9 tonnes.
Baleen whales, also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea which use keratinaceous baleen plates in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae, Balaenopteridae (rorquals), Eschrichtiidae and Cetotheriidae. There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychians, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago.
Balaenidae is a family of whales of the parvorder Mysticeti that contains mostly fossil taxa and two living genera: the right whale, and the closely related bowhead whale.
Neobalaenidae is a family of baleen whales including the extant pygmy right whale. Although traditionally considered related to balaenids, recent studies by Fordyce and Marx (2013) and Ludovic Dutoit and colleagues (2023) have recovered the living pygmy right whale as a member of Cetotheriidae, making it the only extant cetotheriid. Not all authors agree with this placement.
The pygmy right whale is a species of baleen whale. It may be a member of the cetotheres, a family of baleen whales which until 2012 were thought to be extinct; C. marginata has otherwise been considered the sole member of the family Neobalaenidae and is the only member of the genus Caperea. First described by John Edward Gray in 1846, it is the smallest of the baleen whales, ranging between 6 and 6.5 metres in length and 3,000 and 3,500 kilograms in mass. Despite its name, the pygmy right whale may have more in common with the gray whale and rorquals than the bowhead and right whales.
Balaenoptera is a genus of rorquals containing eight extant species. Balaenoptera comprises all but two of the extant species in its family ; the genus is currently polyphyletic, with the two aforementioned species being phylogenetically nested within it.
Eobalaenoptera is an extinct genus of baleen whale belonging to Balaenopteroidea.
Cetotherium is an extinct genus of baleen whales from the family Cetotheriidae.
Cetotheriidae is a family of baleen whales. The family is known to have existed from the Late Oligocene to the Early Pleistocene before going extinct. Although some phylogenetic studies conducted by Fordyce & Marx 2013 recovered the living pygmy right whale as a member of Cetotheriidae, making the pygmy right whale the only living cetotheriid, other authors either dispute this placement or recover Neobalaenidae as a sister group to Cetotheriidae.
Parietobalaena is an extinct genus of baleen whale, belonging to the family Pelocetidae. Fossils are found in Miocene-aged marine strata in North America, Europe, Australia and Japan.
Herpetocetus is a genus of cetotheriid mysticete in the subfamily Herpetocetinae.
Protororqualus is a genus of extinct rorqual from the late Pliocene of Mount Pulgnasco, Italy.
Archaebalaenoptera is a genus of extinct rorqual known from late Miocene to Pliocene-age marine deposits of the Netherlands, northern Italy, and Peru.
Plesiocetus is a genus of extinct balaenopterids found worldwide. It has had a chequered taxonomic history, having served as a wastebasket genus for a handful of mysticete species.
Eschrichtioides is an extinct genus of baleen whale known from the early Pliocene of northern Italy. Its type species, E. gastaldii, had a complex taxonomic history, starting as a cetothere, then as an extinct member of Balaenoptera, before being finally recognized as a relative of the gray whale.
Cetotheriopsis is a genus of extinct cetaceans of the family Cetotheriopsidae.
Aglaocetus is a genus of extinct baleen whales known from the Miocene of Patagonia, the US Eastern Seaboard, Japan and the Low Countries. It was once considered a member of Cetotheriidae along with many other putative cetotheres, but was recently recognized as representing a distinct family from true Cetotheriidae.
Isocetus is an extinct genus of baleen whale belonging to the clade Thalassotherii. Remains have been found in middle Miocene marine deposits in Belgium.
Fragilicetus is an extinct genus of rorqual from Early Pliocene deposits in Belgium.
