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Aetiocetidae
Aetiocetidae is an extinct Family (biology), family of toothed Baleen whale, baleen whales known from the Oligocene and latest Eocene, so far only from rocks deposited in the North Pacific Ocean. The whales ranged in size from long. Many of the described specimens were discovered from the Upper Oligocene of the Japanese Morawan Formation, the largest known one from the Morawan's Upper tuffaceous siltstone. Other formally described extinct toothed mysticetis from this time are smaller, from in length. Mysticeti with true baleen are seen in fossils from the Upper Oligocene. The monophyly of the family is still uncertain, as are the evolutionary relationship between the early toothed baleen whales (Aetiocetidae, Mammalodontidae, and Llanocetidae) and the early and extant Edentulism, edentulous baleen whales. However, the cladistic analyses of ''Coronodon'' and ''Mystacodon'' seem to indicate that Aetiocetidae and Llanocetidae are more closely related to crown Mysticeti than to Mamma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aetiocetus Cotylalveus
''Aetiocetus'' is a genus of extinct basal mysticete, or baleen whale that lived , in the Oligocene in the North Pacific ocean, around Japan, Mexico, and Oregon, U.S. It was first described by Douglas Emlong in 1966 and currently contains known four species, ''A. cotylalveus'', ''A. polydentatus'', ''A. tomitai'', and ''A. weltoni''. These whales are remarkable for their retention of teeth and presence of nutrient foramina, indicating that they possessed baleen. Thus, ''Aetiocetus'' represents the transition from teeth to baleen in Oligocene mysticetes. Baleen is a highly derived character, or synapomorphy, of mysticetes, and is a keratinous structure that grows from the palate, or roof of the mouth, of the whale. The presence of baleen is inferred from the fossil record in the skull of ''Aetiocetus''. ''Aetiocetus'' is known from both sides of the Pacific Ocean: it was first documented in Oregon, United States, but it is also known from Japan and Mexico. The genus is current ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aetiocetidae
Aetiocetidae is an extinct Family (biology), family of toothed Baleen whale, baleen whales known from the Oligocene and latest Eocene, so far only from rocks deposited in the North Pacific Ocean. The whales ranged in size from long. Many of the described specimens were discovered from the Upper Oligocene of the Japanese Morawan Formation, the largest known one from the Morawan's Upper tuffaceous siltstone. Other formally described extinct toothed mysticetis from this time are smaller, from in length. Mysticeti with true baleen are seen in fossils from the Upper Oligocene. The monophyly of the family is still uncertain, as are the evolutionary relationship between the early toothed baleen whales (Aetiocetidae, Mammalodontidae, and Llanocetidae) and the early and extant Edentulism, edentulous baleen whales. However, the cladistic analyses of ''Coronodon'' and ''Mystacodon'' seem to indicate that Aetiocetidae and Llanocetidae are more closely related to crown Mysticeti than to Mamma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ashorocetus
''Ashorocetus'' is a monotypic genus of an extinct primitive baleen whale of the family Aetiocetidae. It was named by , and contains one species, ''A. eguchii''. Fossils of this whale are found from the Chattian Morawan formation, near Ashoro, of upper Oligocene () Hokkaido, Japan (, paleocoordinates ). ''Ashorocetus eguchii'' was described based on a partial skull and is named after the type locality and Kenichiro Eguchi of the Ashoro Museum of Paleontology. Description described four new aetiocetid species, of whom ''Ashorocetus eguchii'' was the most primitive. It has a neatly telescoped skull and is closely related to ''Chonecetus'', another primitive aetiocetid. Barnes et al. also described '' Morawanocetus yabukii'', a more derived species with a foreshortened braincase, intermediate between ''Chonecetus'' and ''Aetiocetus''; ''Aetiocetus tomitai'', the most primitive ''Aetiocetus'' discovered; and ''Aetiocetus polydentatus'', the most derived ''Aetiocetus'' with a hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morawanocetus
''Morawanocetus'' is a genus of extinct primitive baleen whale from the family Aetiocetidae that existed during the Chattian stage of the Oligocene epoch. Its fossils have been found in the North Pacific. ''Morawanocetus'' was named by Barnes ''et al.'' in 1995, who described the species, ''M. yabukii''. Three new species, dating from 17 to 19 million years ago, were unearthed between 2000 and 2005 in a road-widening project in California. These three new specimens of ''Morawanocetus'', a genus thought to have gone extinct some five million years earlier, were discovered next to a fourth specimen, still under preparation, which clearly has archaeocete dentition.. CSUF. Retrieved 11 January 2014. ''Morawanocetus'' was divergent, with wide crania, elaborate cheek, tooth crowns, and short necks. The first fossils of ''Morawanocetus'' were found in the Chattian-aged Morawan Formation of Upper Oligocene Hokkaido. The more recent findings are the first ''Morawanocetus'' fossils f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mysticeti
Baleen whales (), also known as whalebone whales, are marine mammals of the parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use baleen plates (or "whalebone") in their mouths to sieve plankton from the water. Mysticeti comprises the families Balaenidae (right and bowhead whales), Balaenopteridae ( rorquals), Eschrichtiidae (the gray whale) and Cetotheriidae (the pygmy right whale). 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. Baleen whales range in size from the and pygmy right whale to the and blue whale, the largest known animal to have ever existed. They are sexually dimorphic. Baleen whales can have streamlined or large bodies, depending on the feeding behavior, and two l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baleen Whale
Baleen whales (), also known as whalebone whales, are marine mammals of the order (biology), parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use baleen plates (or "whalebone") in their mouths to sieve plankton from the water. Mysticeti comprises the family (biology), families Balaenidae (right whale, right and Bowhead whale, bowhead whales), Balaenopteridae (rorquals), Eschrichtiidae (the gray whale) and Cetotheriidae (the pygmy right whale). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from Mesonychia, mesonychians, molecular phylogenetics, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 mya (unit), million years ago. Baleen whales range in size from the and pygmy right whale to the and blue whale, the Largest organisms, largest known animal to have ever existed. They ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fucaia
''Fucaia'' is an extinct genus of primitive baleen whale belonging to the family Aetiocetidae that is known from Oligocene and latest Eocene marine deposits on Vancouver Island, Canada, the Olympic Peninsula, Washington State, and Oregon. Taxonomy Three species are now recognized; ''F. buelli'', ''F. goedertorum'' (Barnes et al. 1995), and ''F''. ''humilis''. ''Fucaia'' ''humilis'' is latest Eocene in age and thus the oldest mysticete in the Northern Hemisphere, ''F. buelli'' is of early Oligocene (Rupelian) age, while ''F. goedertorum'' is younger. The latter was originally described as a species of '' Chonecetus'' before it was recognized as more closely related to ''buelli'' than to the ''Chonecetus'' type species.L. G. Barnes, M. Kimura, H. Furusawa and H. Sawamura. 1995. Classification and distribution of Oligocene Aetiocetidae (Mammalia; Cetacea; Mysticeti) from western North America and Japan. The Island Arc 3(4):392-431 Biology The tooth structure of ''Fucaia'' indicates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kaaucetus
''Kaaucetus'' is an extinct genus of aetiocetid that inhabited what is now the coast of Mexico during the Chattian stage of the Oligocene epoch. It contains a single species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ..., ''K. thesaurus''. References {{Taxonbar, from=Q132128887 Oligocene mammals of North America Fossil taxa described in 2022 Aetiocetidae Prehistoric cetacean genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salishicetus
''Salishicetus'' is an extinct genus of aetiocetid baleen whale from the Late Oligocene discovered in Washington state with one species: ''S. meadi''. Like other ancient baleen whales, ''Salishicetus'' had teeth, and used these for either suction feeding or to catch large prey. The name refers to the Salish Sea, which it was found near, which itself honors the Salish tribes of the Pacific Northwest The Pacific Northwest (PNW; ) is a geographic region in Western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though no official boundary exists, the most common ... region. References Aetiocetidae Oligocene cetaceans Oligocene mammals of North America Monotypic prehistoric cetacean genera Fossil taxa described in 2018 {{Paleo-whale-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morawan Formation
The Morawan Formation is a Chattian age siliceous marine geological formation of the Oligo-Miocene Japanese Kawakami Group of eastern Hokkaido prefecture. The formation is fossil rich and contains source units where toothed baleen whales (Aetiocetidae) and Desmostylians have been discovered. The Morawan Formation is a very siliceous unit containing hard platy shales interbedded with tuffaceous mudstones and sandstones, and some pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula .... The unnamed lower member is a hard platy shale alternating with beds of tuffaceous mudstones and sandstones, the Kamirawan member is a tuffaceous sandstone with pumice, the Lower Hard Shale is a very siliceous hard shale with tuffaceous sandstones and mudstones, and the Middle Hard Shales and the Upp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
