Eschrichtiidae or the gray whales is a family of baleen whale with a single extant species, the gray whale, as well as three described fossil genera: Archaeschrichtius and Eschrichtioides from the Miocene and Pliocene of Italy respectively, and Gricetoides from the Pliocene of North Carolina. More recent phylogenetic studies have found this family to be invalid, with its members nesting inside the Balaenopteridae. The names of the extant genus and the family honours Danish zoologist Daniel Eschricht.
Pakicetidae is an extinct family of Archaeoceti that lived during the Early Eocene in Pakistan. Unlike modern cetaceans, they had well developed limbs and were capable of walking.
Rorquals are the largest group of baleen whales, comprising the family Balaenopteridae, which contains nine extant species in two genera. They include the largest known 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.
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.
Parabalaenoptera is a genus of prehistoric baleen whale found in Marin County, California. The type species is P. baulinensis. It was estimated to be about the size of the modern gray whale, about 16 metres (52 ft) long. It lived during the late Miocene.
Diunatans is an extinct genus of rorqual. It lived in the North Sea during the Early Pliocene. Two specimens have been found from the Netherlands. They were collected from the Kattendijk Formation in the province of Zeeland, which is Zanclean in age. Diunatans is considered to be a stem balaenopterid because it falls outside the Balaenoptera+Megaptera clade, which includes all living rorquals.
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, including the Temblor and Itahashi formations. Based on previous estimates of juvenile specimens, Tsai (2017) suggested a body size of 12-15 m for P. yamaokai, akin to that of the gray whale.
Titanocetus is a genus of extinct cetaceans closely related to the family Cetotheriidae.
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 rorquals 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.
Miocaperea is an extinct genus of pygmy right whale from the Late Miocene Pisco Formation of Peru. Its type species is Miocaperea pulchra.
Horopeta is a genus of baleen whale from the Late Oligocene (Chattian) Kokoamu Greensand of New Zealand.
Incakujira is a genus of rorqual whales that lived during the Late Miocene epoch in what are now the coasts of Peru, about 8 million to 7.3 million years ago. It contains two species, Incakujira anillodefuego and Incakujira fordycei. The type species, I. anillodefuego, was named and described in 2016. The second species was described in 2024. All known specimens have been found in the sediments of the Pisco Formation of Peru, which dates to the Late Miocene.
Inticetus is an extinct genus of Early Miocene odontocete from the Chilcatay Formation, Pisco Basin, Peru.
Miophyseter is an extinct genus of sperm whale in the superfamily Physeteroidea. It includes only one species, M. chitaensis, that was described in 2022 from the lower Miocene (Burdigalian) of Toyohama Formation, Chita District, Aichi Prefecture, Japan. This species is known from the well-preserved cranium with detached teeth and ear bones. Miophyseter is part of the Physeteroidea stem group, but more closely related to the crown group than to the macroraptorial sperm whales known from middle and late Miocene. Miophyster may have had an adaptation to deep diving and / or developed pterygoid muscles for active biting. The researchers made this conclusion judging by the presence of a deep and large notch on the ventral surface of the palatine bone and pterygoid.
