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Paleoparadoxiidae
The Desmostylia (from Greek δεσμά ''desma'', "bundle", and στῦλος ''stylos'', "pillar") are an extinct order of aquatic mammals that existed from the early Oligocene (Rupelian) to the late Miocene (Tortonian) (). Desmostylians are the only known extinct order of marine mammals. The Desmostylia, together with Sirenia and Proboscidea (and possibly Embrithopoda), have traditionally been assigned to the afrotherian clade Tethytheria, a group named after the paleoocean Tethys Ocean, Tethys around which they originally evolved. The relationship between the Desmostylia and the other orders within the Tethytheria has been disputed; if the common ancestor of all tethytheres was semiaquatic, the Proboscidea became secondarily terrestrial; alternatively, the Desmostylia and Sirenia could have evolved independently into aquatic mammals. The assignment of Desmostylia to Afrotheria has always been problematic from a biogeographic standpoint, given that Africa was the locus of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoparadoxiidae
The Desmostylia (from Greek δεσμά ''desma'', "bundle", and στῦλος ''stylos'', "pillar") are an extinct order of aquatic mammals that existed from the early Oligocene (Rupelian) to the late Miocene (Tortonian) (). Desmostylians are the only known extinct order of marine mammals. The Desmostylia, together with Sirenia and Proboscidea (and possibly Embrithopoda), have traditionally been assigned to the afrotherian clade Tethytheria, a group named after the paleoocean Tethys Ocean, Tethys around which they originally evolved. The relationship between the Desmostylia and the other orders within the Tethytheria has been disputed; if the common ancestor of all tethytheres was semiaquatic, the Proboscidea became secondarily terrestrial; alternatively, the Desmostylia and Sirenia could have evolved independently into aquatic mammals. The assignment of Desmostylia to Afrotheria has always been problematic from a biogeographic standpoint, given that Africa was the locus of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ashoroa
''Ashoroa'' (named after its type locality Ashoro, Hokkaido) is an extinct genus of desmostylian, aquatic, herbivorous mammal. Fossils of ''Ashoroa'' have been found in the Morawan Formation on Hokkaido, Japan (, paleocoordinates ) and were dated to the late Oligocene. Description ''Ashoroa'' is the smallest and one of the oldest desmostylians with an estimated body length of . It is known from a rib, a humerus, a femur, and three vertebrae of the single species and holotype, ''Ashoroa laticosta''. ''Ashoroa'' had pachyosteosclerotic (large and dense) bones. The ribs are broader than in other desmostylians, similar to sirenian ribs, and very dense, like those of '' Behemotops'' and ''Paleoparadoxia''; and extant, semi-aquatic mammals such as Eurasian beaver and hippopotamus, but not as dense as in sirenians. The recovered long bones lack inner cavities, like in ''Paleoparadoxia'' and '' Desmostylus'', and the trabecula A trabecula (plural trabeculae, from Latin for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmostylidae
Desmostylidae is an extinct family of herbivorous marine mammals belonging to the order of Desmostylia. They lived in the coastal waters of the northern Pacific Ocean from the Early Oligocene (Rupelian) through the Late Miocene (Tortonian) (33.9 mya—7.2 MYA) . Retrieved April 2020.K. Chiba, A. R. Fiorillo, L. L. Jacobs, Y. Kimura, Y. Kobayashi, N. Kohno, Y. Nishida, M. J. Polcyn, and K. Tanaka. 2016. A new desmostylian mammal from Unalaska (USA) and the robust Sanjussen jaw from Hokkaido (Japan), with comments on feeding in derived desmostylids. Historical Biology 28(1-2):289-303 existing for approximately . Taxonomy and systematics Desmostylidae was named by . It was assigned to Sirenia by Osborn (1905); to Proboscidea by Abel (1919); to Desmostyliformes by Simpson (1932), Kretzoi (1941) and Reinhart (1959); to Desmostylia by McKenna and Bell (1997); and to Desmostylia by Carroll (1988), Inuzuka et al. (1995), Inuzuka (2000) and Barnes and Goedert (2001). found a subadult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Behemotops
''Behemotops'' (from the Biblical monster Behemoth, by Linnaeus and others believed to be a hippo) is an extinct genus of herbivorous marine mammal. It lived from the Early Oligocene (Rupelian) through the Late Oligocene (33.9 mya—23 Mya), existing for approximately . It is the most primitive known desmostylian, believed to be close to the ancestry of all other desmostylians. History of discovery ''B. proteus'' In 1976, Emlong discovered a juvenile mandible — USNM 244035 — on Olympic Peninsula, Clallam County, Washington (, paleocoordinates ) which made the holotype of ''B. proteus''. Teeth of a young adult — LACM 124106 – was found in the same rock unit in 1986. More complete material of ''B. proteus'' was found on Vancouver Island, British Columbia in 2007: the left side of an entire skull with several teeth, a partial scapula, an almost complete humerus, and several ribs and vertebrae. The cranial features of this specimen were s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afrotheria
Afrotheria ( from Latin ''Afro-'' "of Africa" + ''theria'' "wild beast") is a clade of mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephant shrews (also known as sengis), tenrecs, aardvarks, hyraxes, elephants, sea cows, and several extinct clades. Most groups of afrotheres share little or no superficial resemblance, and their similarities have only become known in recent times because of genetics and molecular studies. Many afrothere groups are found mostly or exclusively in Africa, reflecting the fact that Africa was an island continent from the Cretaceous until the early Miocene around 20 million years ago, when Afro-Arabia collided with Eurasia. Because Africa was isolated by water, Laurasian groups of mammals such as insectivores, rodents, lagomorphs, carnivorans and ungulates could not reach Africa for much of the early to mid-Cenozoic. Instead, the niches occupied by those groups on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tethytheria
Tethytheria is a clade of mammals that includes the sirenians and proboscideans, as well as the extinct order Embrithopoda. Though there is strong anatomical and molecular support for the monophyly of Tethytheria, the interrelationships between the included taxa remain disputed. The tethytheres are united by several characters, including anteriorly facing orbits and more or less bilophodont cheek teeth (double transverse ridges on the crowns of the teeth). Proboscidea and Sirenia are linked together based on auditory characters in their petrosal bones, but this link may be a homoplasy. Desmostylians, traditionally considered tethytheres, have been tentatively assigned to Perissodactyla, along with the Early Eocene family Anthracobunidae, which was considered a sister group to Tethytheria. Systematics Cladogram modified from and . Classification Classification modified from . * Clade Tethytheria ** order †Embrithopoda *** † Phenacolophidae *** †Arsinoitheriidae ** order ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tethys Ocean
The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents of Gondwana and Laurasia, before the opening of the Indian and Atlantic oceans during the Cretaceous Period. It was preceded by the Paleo-Tethys Ocean, which lasted between the Cambrian and the Early Triassic, while the Neotethys formed during the Late Triassic and lasted until the early Eocene (about 50 million years ago) when it completely closed. A portion known as the Paratethys formed during the Late Jurassic, was isolated during the Oligocene (34 million years ago) and lasted up to the Pliocene (about 5 million years ago), when it largely dried out. Many major seas and lakes of Europe and Western Asia, including the Mediterranean Sea, the Black Sea, the Caspian Sea, and the Aral Sea are thought to be remnants of the Paratethys. Ety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Rim
The Pacific Rim comprises the lands around the rim of the Pacific Ocean. The ''Pacific Basin'' includes the Pacific Rim and the islands in the Pacific Ocean. The Pacific Rim roughly overlaps with the geologic Pacific Ring of Fire. List of countries on the Pacific Rim This is a list of countries that are generally considered to be a part of the Pacific Rim, since they lie along the Pacific Ocean. Arranging from north to south, west to east in directional order. Oceania * Oceania (sovereign states) ** ** ** ** ** ** ** ** ** ** ** ** ** ** * Oceania ( dependent territories) ** British Overseas Territory *** ** External territory of Australia *** ** French overseas collectivities *** *** *** ** Insular Chile *** ** Realm of New Zealand *** *** *** ** United States insular areas *** *** *** ** United States *** Americas * North America ** ** ** ** ** ** ** ** ** * South America ** ** ** ** Asia * Russian Federation * Eas ... [...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] |
Proboscidea
The Proboscidea (; , ) are a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. From the mid-Miocene onwards, most proboscideans were very large. The largest land mammal of all time may have been a proboscidean; ''Palaeoloxodon namadicus'' was up to at the shoulder and may have weighed up to , almost double the weight of some sauropods like ''Diplodocus carnegii''. The largest extant proboscidean is the African bush elephant, with a record of size of at the shoulder and . In addition to their enormous size, later proboscideans are distinguished by tusks and long, muscular trunks, which were less developed or absent in early proboscideans. Three species of elephant are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. Elephantidae is the only surviving family of the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
