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Maddenia (mammal)
''Maddenia'' is an extinct genus of astrapothere, meridiungulate herbivore mammals characterised by its large tusks and the development of proboscis, endemic of South America. This genus was discovered in an outcrop near to the Lake Colhué Huapi in the place La Cantera, in the Chubut Province, in Argentina, in sediments corresponding to the Sarmiento Formation, that dates of the Late Oligocene (Deseadan South American land mammal age).''Maddenia'' at .org [...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] |
Molar (tooth)
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth", from ''mola'', millstone and ''dens'', tooth. Molars show a great deal of diversity in size and shape across mammal groups. The third molar of humans is sometimes vestigial. Human anatomy In humans, the molar teeth have either four or five cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies from individual to individual. Race can also affect the age at which this occurs, with statistical variations between groups. In some cases, it may not even erupt at all. The human mouth contains upper (maxillary) and lower (mandib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scaglia (mammal)
''Scaglia'' is an extinct genus of South American astrapotherid land mammal that lived during the Eocene (Casamayoran to Divisaderan in the SALMA classification). Etymology The genus was named after Argentinian naturalist Galileo Juan Scaglia, and the type species after Argentinian palaeontologist Lucas Kraglievich. Description Its type specimen, recovered from the Sarmiento Formation of Argentina, is MMCNT-MdP 207. Like ''Albertogaudrya'', ''Scaglia'' was the size of a sheep or a small tapir, hence among the larger mammals in South America at that time. Phylogeny Cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ... according to Bond ''et'' al., 2011, standing out the phylogenetic position of ''Scaglia'': References Bibliography * * Further rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctodon
''Antarctodon'' is an extinct genus of mammals from the Early Eocene (late Ypresian age). It is a basal astrapotherian which lived in what is now Seymour Island, Antarctic Peninsula, at that moment still connected to South America where most of the astrapotherians were found. The holotype and only specimen MLP 08-XI-30-1, an isolated right p4 or m1, was found in the Telm 5 Member of the La Meseta Formation in West Antarctica.''Antarctodon'' at .org It was first named by Mariano Bond, Alejandro Kramarz, Ross D. E. MacPhee and Marcelo Reguero in |
Tetragonostylops
''Tetragonostylops'' is an extinct genus of mammal, related to Astrapotheria. It lived during the Late Paleocene, and its fossils were discovered in South America. Description This genus is only known from incomplete remains, notably a well-preserved mandible and a fragmentary skull. Like other astrapotheres, ''Tetragonostylops'' may have had a strong elongated body, and a long, flat skull. The skull was 20 centimeters long, and the entire body was supposedly one meter long. Its mandible was strong, and endowed with an elongated cylindrical symphysis. The mandibular condyle was elevated, and the coronoid process was high, but lower than in its relative ''Trigonostylops''. The shape of their molars was different, with ''Tetragonostylops'' having more squared molars (hence his name, ''Tetragon-'' meaning "four corners"), and had an infraorbital canal, which does not appear in ''Trigonostylops''. The molars were brachyodont, like those of ''Trigonostylops'', and the canines were st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonostylops
''Trigonostylops'' is an extinct genus of South American meridiungulatan ungulate, from the Late Paleocene to Late Eocene (Itaboraian to Tinguirirican in the SALMA classification) of South America (Argentina and Peru) and Antarctica (Seymour Island). It is the only member of the family Trigonostylopidae. Description A complete skull of the type species, ''T. wortmani'', has been found, and it has been classified as an astrapothere based on its large lower incisors. Phylogeny Cladogram based in the phylogenetic analysis published by Vallejo Pareja ''et al''., 2015, showing the position of ''Trigonostylops'':Vallejo Pareja et al., 2015 Distribution Fossils of ''Trigonostylops'' have been found in:''Trigonostylops'' at |
Eoastrapostylops
''Eoastrapostylops'' is an extinct genus of astrapothere that lived during the Late Paleocene in what is now Argentina. Description This animal was small in size; the skull was 9 centimeters long and the total length of the animal probably just exceeded half a meter. ''Eoastrapostylops'' possessed a short muzzle ; its canines were well developed but not yet derived into large fangs, as was the case in later South American ungulates such as ''Trigonostylops'', and the nasal bones were not retracted, indicating the absence of the typical proboscis exhibited by later forms. The dentition of ''Eoastrapostylops'' recalls that of its later relative, ''Trigonostylops''. molars and premolars were low-crowned and lophoselenodont-shaped. The fourth premolar was molarized, while both the fourth upper premolar and the third upper molar were triangularly shaped and lacked an hypoconus. Classification ''Eoastrapostylops riolorense'' was first described in 1981, based on fossils found in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrapotheriidae
Astrapotheriidae is an extinct family of herbivorous South American land mammals that lived from the Late Eocene (Mustersan SALMA) to the Middle Miocene (Laventan SALMA) . The most derived of the astrapotherians, they were also the largest and most specialized mammals in the Tertiary of South America. There are two sister taxa: Eoastrapostylopidae and Trigonostylopidae. Around 1900, Argentine paleontologist Florentino Ameghino described eight Colhuehuapian (Early Miocene) species from specimens he found south of Lake Colhué Huapi in Patagonia and grouped them into three genera: '' Parastrapotherium'', ''Astrapotherium'', and '' Astrapothericulus''. It was obvious to Ameghino that these species represented a great diversity, ranging in size from a peccary to a rhinoceros, but his description was based entirely on fragmentary and not always comparable dental remains. Other expeditions to Patagonia have subsequently recovered considerably more complete materials. Genera According ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albertogaudrya
''Albertogaudrya'' is an extinct genus of astrapotherian mammal that lived in present-day Salta, Argentina (, paleocoordinates ) during the Eocene (Casamayoran SALMA The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as a ...) .''Albertogaudrya'' at Fossilworks.org Fossils of ''Albertogaudrya'' have been found in the Lumbrera and [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granastrapotherium
''Granastrapotherium'' is an extinct genus of ungulate mammals, described from remains found in rocks of the Honda Group in the Tatacoa Desert, in the Colombian departments of Huila and Tolima, at the Miocene fossil site La Venta. The only species formally recognized is ''Granastrapotherium snorki'' (from Spanish, ''gran'', "great"; ''Astrapotherium'', "lightning beast"; and snorkel, breathing tube, in reference to the trunk). Remains found in Bolivia and Peru, seem to belong to ''Granastrapotherium'' or a very similar animal. Description This astrapothere differs from its coeval, the uruguaytheriine astrapotheriid ''Xenastrapotherium'' by their larger size, between 3 and 4 tonnes, with tusks about one meter long, making it one of the largest representatives of Astrapotheria, only surpassed by some species of ''Parastrapotherium''. Other differences include the presence of only one premolar, the lack of incisors in both jaws and the disposition of the canine tooth, which are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrapotherium
''Astrapotherium'' ("lightning beast") is an extinct genus of South American mammals that vaguely resembled a small elephant or large tapir. However, it was unrelated to elephants or tapirs, but was instead related to other extinct South American ungulates. Fossils have been dated from the Early to Middle Miocene. Fossil remains of the type species ''A. magnus'' have been found in the Santa Cruz Formation in Argentina. Other fossils have been found in the Deseado, Sarmiento, and Aisol Formations of Argentina and Chile (Cura-Mallín Group).''Astrapotherium'' at .org Description [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
