| Kentriodontidae Temporal range: | |
|---|---|
 | |
| Rudicetus squalodontoides skull | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Clade: | Delphinida |
| Superfamily: | Delphinoidea |
| Family: | † Kentriodontidae Slijper, 1936 |
| Genera | |
See text | |
Kentriodontidae is an extinct family of odontocete whales related to modern dolphins. The Kentriodontidae lived from the Oligocene to the Pliocene before going extinct. [1]
Kentriodontids have been variously divided into three or four subfamilies: Kampholophinae, Kentriodontinae, Lophocetinae, and Pithanodelphinae. [1] However, some cladistic studies have recovered Kentriodontidae as paraphyletic [2] [3] [4] [5] [6] while others have recovered the family as monophyletic. [7] [8]
For instance, Miminiacetus may be a close relative of Lipotidae, Brevirostrodelpis is basal to other delphinidans, [6] Incacetus is probably a member of Inioidea, [5] and Atocetus and Lophocetus have been recovered as a pontoporiid and ziphiid sister taxon respectively, while Hadrodelphis , Kampholophos, Macrokentriodon , and Miminiacetus are recovered in a clade phylogenetically intermediate between Kentriodon and derived delphinidans ((Inioidea+Lipotidae)+Delphinoidea). [9] Peredo et al. (2018) restrict Kentriodon to Kampholophos, Kentriodon, Rudicetus, and Wimahl, and remove Pithanodelphininae and its putative constituent genera ( Leptodelphis , Pithanodelphis , Sarmatodelphis , Sophianacetus , and Tagicetus ) as well as Microphocaena from Kentriodontidae. [10]
Lipotidae is a family of river dolphins containing the possibly extinct baiji of China and the fossil genus Parapontoporia from the Late Miocene and Pliocene of the Pacific coast of North America. The genus Prolipotes, which is based on a mandible fragment from Neogene coastal deposits in Guangxi, China, has been classified as an extinct relative of the baiji, but is dubious.
Kentriodon is an extinct genus of toothed whale related to modern-day dolphins. Fossils have been found in North America, Europe and Japan. Several species have been described.
Sagmatias was a genus of dolphins, defined in 1866 by Edward Drinker Cope with Peale's dolphin as type species, described as Sagmatias amblodon. It has been proposed to resurrect the genus to include four species of oceanic dolphins currently classified in the genus Lagenorhynchus. Mitochondrial DNA studies have indicated that Pacific white-sided dolphin, Peale's dolphin, dusky dolphin and hourglass dolphin are more closely related to dolphins in the Lissodelphininae subfamily, than to the two other members of the genus: Atlantic white-sided dolphin and white-beaked dolphin. This phylogenetic relationship is further supported by cladistic analysis of morphological characters. However, resurrection of the genus Sagmatias has not been accepted by the Society for Marine Mammalogy's taxonomic Committee, because the finer details of the phylogenetic relationships between the four species in the proposed Sagmatias genus and the four species of dolphins in the genus Cephalorhynchus remains to be resolved. Genetic and bioacoustical evidence suggest that Peale's dolphin and hourglass dolphin are closer related to the Cephalorhynchus species than to the Pacific white-sided dolphin and dusky dolphin, which, if true, would make the genus Sagmatias paraphyletic.
Delphinoidea is the largest group of toothed whales with 66 genera in 6 families. The largest living member of the superfamily is the killer whale, which can reach 6 tons, while the smallest is the vaquita.
Meherrinia is an extinct genus of inioid river dolphin from the Meherrin River, North Carolina, in the United States. First described in 2012, the dolphin is, in most respects, intermediate in form between the living Amazon river dolphin and the La Plata dolphin, although it is probably more closely related to the former. However, the fossil was discovered in what are believed to be marine deposits, dating from the late Miocene, whereas the Amazon river dolphin is an exclusively freshwater species. Meherrinia therefore was, as of 2012, the only known marine genus of the family Iniidae, although others have been discovered since. Only one species is known.
The Astoria Formation is a geologic formation in Washington state & Oregon. It preserves fossils dating back to the early to middle Miocene.
The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica and Arequipa. The approximately 640 metres (2,100 ft) thick formation was deposited in the Pisco Basin, spanning an age from the Middle Miocene up to the Early Pleistocene, roughly from 15 to 2 Ma. The tuffaceous sandstones, diatomaceous siltstones, conglomerates and dolomites were deposited in a lagoonal to near-shore environment, in bays similar to other Pacific South American formations as the Bahía Inglesa and Coquimbo Formations of Chile.
Atocetus is an extinct genus of pontoporiid dolphin found in Miocene-age marine deposits in Peru and California.
Macrokentriodon is an extinct genus of giant dolphin once assigned to the paraphyletic/polyphyletic family Kentriodontidae. Remains have been found in the late Miocene (Serravallian) Choptank Formation of United States.
Liolithax is an extinct genus of dolphin from the Middle Miocene (Serravallian) Temblor Formation of California.
Lophocetus is an extinct genus of dolphin belonging to the clade Delphinida that is known from late Miocene (Tortonian) marine deposits in California and Maryland. Although usually placed in Kentriodontidae, recent studies have found it only distantly related to Kentriodon.
Hadrodelphis is an extinct genus of dolphin once assigned to the paraphyletic/polyphyletic family Kentriodontidae. Remains have been found in the middle Miocene (Langhian) Calvert Formation of United States.
Brujadelphis is an extinct genus of river dolphin-like cetaceans of uncertain family placement from the Late Miocene epoch (Serravallian) of present-day Peru. The type species is Brujadelphis ankylorostris, recovered from the Pisco Formation.
Tagicetus is an extinct genus of dolphin belonging to the polyphyletic family Kentriodontidae.
Eodelphinus is an extinct genus of oceanic dolphins belonging to the family Delphinidae.
Wimahl is a genus of cetacean that belongs to the family Kentriodontidae. It lived in the Miocene period. It contains a single species, Wimahl chinookensis. The name Wimahl translates to "big river" in the local Chinook language.
Archaeophocaena teshioensis is a species of extinct porpoise from the Late Miocene Koetoi Formation of Japan living around 6.4–5.5 million years ago (mya). The holotype specimen comprises a partial skull. The animal, along with Miophocaena and Pterophocaena, seem to represent an intermediary phase between porpoises and dolphins. The genus name derives from Ancient Greek archaeo, "ancient," and Latin phocaena, "porpoise"; the species name honors the Teshio District where the holotype was discovered.
Miophocaena nishinoi is an extinct species of porpoise from the Late Miocene Koetoi Formation of Japan, dating to around 6.4–5.5 million years ago (mya), represented by a partial skull. the genus name derives from Ancient Greek mio for the Miocene, and phocaena for "porpoise"; the species name honors the discoverer, Takanobu Nishino. Miophocaena resides in a clade with Archaeophocaena discovered in the same area, and, along with Pterophocaena, represents an intermediate phase between porpoises and dolphins.
Pterophocaena nishinoi is an extinct species of porpoise discovered in the Late Miocene Wakkanai Formation of Japan dating to 9.3–9.2 million years ago (mya), and may represent an intermediate phase between porpoises and dolphins. It is one of the oldest species discovered, after the Middle Miocene Loxolithax 16–14.8 mya and the Late Miocene Salumiphocaena 12.6–9 mya. The holotype specimen comprises a partial skeleton. The genus name derives from Ancient Greek pteryx, "wing," in reference to its unusually pronounced beak, and Latin phocaena, "porpoise." The species name honors the discoverer of the holotype, Takanobu Nishino.
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