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Chonecetus
''Chonecetus'' is an extinct genus of primitive baleen whale of the family Aetiocetidae that lived in the Oligocene period. Its fossils have been found in Canada, in the northeast Pacific. It was first named by L.S. Russell in 1968, and contains one species, ''C. sookensis''. Like ''Aetiocetus'', ''Chonecetus'' possessed both multicusped teeth and the nutrient foramina required for baleen.''Marine Mammals: Evolutionary Biology''; page 62. By Annalisa Berta, James L. Sumich, and Kit M. Kovacs, published 2005; Academic Press. Retrieved on July 1, 2008. ''Chonecetus'' closely resembled a modern Mysticeti, with an elongate, streamlined body supporting a pair of paddle-shaped forelimbs, and a horizontal tail fluke strengthened by fibrous cartilage. Sister Taxa *''Aetiocetus'' *''Ashorocetus'' *''Fucaia'' *''Morawanocetus ''Morawanocetus'' is a genus of extinct primitive baleen whale from the family Aetiocetidae that existed during the Chattian stage of the Oligocene epoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aetiocetus
''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 currently ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baleen Whale
Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae (right and bowhead whales), Balaenopteridae (rorquals and 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 mesonychids, 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 th ... [...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 marine deposits found in Vancouver Island, Canada and Olympic Island, Washington State. Taxonomy Two species, ''F. buelli'' and ''F. goedertorum'' (Barnes et al. 1995). ''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 ''Choncetus'' 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 that it was capable of both raptorial feeding and suction-feeding, like other aetiocetids. Sister taxa *''Aetiocetus'' *''Ashorocetus ''Ashorocetus'' is a monotypic genu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aetiocetidae
Aetiocetidae is an extinct family of toothed baleen whales known from the Oligocene. The whales are from the North Pacific Ocean and 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 edentulous Toothlessness, or edentulism, is the condition of having no teeth. In organisms that naturally have teeth, it is the result of tooth loss. Organisms that never possessed teeth can also be described as edentulous. Examples are the members of the ... baleen whales. Howe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willungacetus
''Willungacetus'' is an extinct genus of primitive baleen whale of the family Aetiocetidae known from the Oligocene of Australia (at Port Willunga, , paleocoordinates ). It is the oldest-known whale from Australia, and the only aetiocetid whale currently known from the Southern Hemisphere. Neville S. Pledge first visited the type locality in 1983 and collected two boulders. These two rocks, however, were forgotten until 2001 when a partial vertebra were discovered within. The site was subsequently revisited and another specimen, a partial cranium, was discovered. Pledge referred a radius, collected from the same cliff in 1994, to his newly named species. Pledge provisionally assigned ''Willungacetus'' to Aetiocetidae, but this assignment still needs to be confirmed. Sister taxa *''Aetiocetus'' *''Ashorocetus'' *''Chonecetus'' *''Morawanocetus ''Morawanocetus'' is a genus of extinct primitive baleen whale from the family Aetiocetidae that existed during the Chattian st ... [...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'' fossi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene Mammals Of North America
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene Cetaceans
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baleen
Baleen is a filter-feeding system inside the mouths of baleen whales. To use baleen, the whale first opens its mouth underwater to take in water. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as a food source for the whale. Baleen is similar to bristles and consists of keratin, the same substance found in human fingernails, skin and hair. Baleen is a skin derivative. Some whales, such as the bowhead whale, have longer baleen than others. Other whales, such as the gray whale, only use one side of their baleen. These baleen bristles are arranged in plates across the upper jaw of whales. Depending on the species, a baleen plate can be long, and weigh up to . Its hairy fringes are called baleen hair or whalebone hair. They are also called baleen bristles, which in sei whales are highly calcified, with calcification functioning to increase their stiffness. Baleen plates are broader at the gumline (base). The plates have b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. 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. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
