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Toxodon
''Toxodon'' (meaning "bow tooth" in reference to the curvature of the teeth) is an extinct genus of South American mammals from the Late Miocene to early Holocene epochs ( Mayoan to Lujanian in the SALMA classification) (about 11.6 million to 11,000 years ago). It is a member of Notoungulata, one of several now extinct orders of hoofed mammals indigenous to South America distinct from living perissodactyls and artiodactyls. It was among the largest and last members of its order, and was probably the most common large hoofed mammal in South America of its time. Taxonomy ''Toxodon'' was one of the last members of Notoungulata, a group of ungulates that had been part of the fauna of South America since the Paleocene. ''Toxodon'' was a member of Toxodontidae a large bodied group including similar, vaguely rhinoceros like forms. Charles Darwin was one of the first to collect ''Toxodon'' fossils, after paying 18 pence for a ''T. platensis'' skull from a farmer in Urug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxodontidae
Toxodontidae is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene (11,000 BP) of South America, with one genus, '' Mixotoxodon'', also known from the Pleistocene of Central America and southwestern North America (Texas).E. Lundelius, et al. 2013. The first occurrence of a toxodont (Mammalia, Notoungulata) in the United States. ''Journal of Vertebrate Paleontology'', Vol 33, No 1, pp. 229–23DOI:10.1080/02724634.2012.711405/ref> They somewhat resembled rhinoceroses, and had teeth with high crowns and open roots, suggesting that they often fed on tough pampas grass. However, isotopic analyses have led to the conclusion that the most recent forms were grazing and browsing generalists. Taxonomy The endemic notoungulate and litoptern ungulates of South America have been shown by studies of collagen and mitochondrial DNA sequences to be a sister group to the perissodactyl Odd-toed ungulates, mammals which constitute the taxonomic order Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxodon Skeleton
''Toxodon'' (meaning "bow tooth" in reference to the curvature of the teeth) is an extinct genus of South American mammals from the Late Miocene to early Holocene epochs (Mayoan to Lujanian in the SALMA classification) (about 11.6 million to 11,000 years ago). It is a member of Notoungulata, one of several now extinct orders of hoofed mammals indigenous to South America distinct from living perissodactyls and artiodactyls. It was among the largest and last members of its order, and was probably the most common large hoofed mammal in South America of its time. Taxonomy ''Toxodon'' was one of the last members of Notoungulata, a group of ungulates that had been part of the fauna of South America since the Paleocene. ''Toxodon'' was a member of Toxodontidae a large bodied group including similar, vaguely rhinoceros like forms. Charles Darwin was one of the first to collect ''Toxodon'' fossils, after paying 18 pence for a ''T. platensis'' skull from a farmer in Urugu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South American Land Mammal Age
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 ages, stages, or intervals and were established using geographic place names where fossil materials where obtained.Flynn & Swisher, 1995 The basic unit of measure is the first/last boundary statement. This shows that the first appearance event of one taxon is known to predate the last appearance event of another. If two taxa are found in the same fossil quarry or at the same stratigraphic horizon, then their age-range zones overlap. Background South America was an island continent for much of the Cenozoic, or the "Age of Mammals". As a result, its mammals evolved in their own unique directions, as Australia and Madagascar still have today. Paleogeographic timeline A simplified paleogeographic timeline of South America: * 66 Ma – Sout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notoungulata
Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resembling animals as disparate as rabbits and rhinoceroses. Notoungulata are the largest group of South American native ungulates, with over 150 genera in 14 families having been described, divided into two major subgroupings, Typotheria and Toxodontia. Notoungulates first diversified during the Eocene. Their diversity declined during the Late Neogene, with only the large toxodontids persisting until the end of the Pleistocene. Collagen analysis suggests that notoungulates are closely related to litopterns, another group of South American ungulates, and their closest living relatives being perissodactyls (odd-toed ungulates), including rhinoceroses, tapirs and equines. but their relationships to other South American ungulates are uncert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrauchenia
''Macrauchenia'' ("long llama", based on the now-invalid llama genus, ''Auchenia'', from Greek "big neck") was a large, long-necked and long-limbed, three-toed native South American mammal in the order Litopterna. The genus gives its name to its family, the Macraucheniidae or "robust litopterns". Like other litopterns, it is most closely related to the odd-toed ungulates ( Perissodactyla), from which litopterns diverged approximately 66 million years ago. The oldest fossils in the genus date to the late Miocene, around seven million years ago, and ''M. patachonica'' disappears from the fossil record during the late Pleistocene, around 20,000-10,000 years ago. ''M. patachonica'' is one of the last and best known member of the family and is known primarily from the Luján Formation in Argentina, but is known from localities across southern South America. Another genus of macraucheniid ''Xenorhinotherium'' was present in northeast Brazil and Venezuela during the Late Pleistocene. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchippus
''Rhynchippus'' ("Snout Horse") is an extinct genus of notoungulate mammals from the Late Oligocene (Deseadan in the SALMA classification) of South America. The genus was first described by Florentino Ameghino in 1897 and the type species is ''R. equinus'', with lectotype MACN A 52–31. Fossils of ''Rhynchippus'' have been found in the Agua de la Piedra and Sarmiento Formations of Argentina, the Salla and Petaca Formations of Bolivia, the Tremembé Formation of Brazil,''Rhynchippus'' at .org and the Moquegua Formation of |
Litoptern
Litopterna (from grc, λῑτή πτέρνα "smooth heel") is an extinct order of fossil hoofed mammals from the Cenozoic era. The order is one of the five great orders of South American ungulates that were endemic to the continent, until the Great American Biotic Interchange brought new ungulate species. Like other endemic South American mammals, their relationship to other mammal groups had long been unclear, but recent genetic and proteomic evidence indicates that their closest living relatives are Perissodactyls (odd-toed ungulates) including horses, rhinoceros, and tapirs, and that litopterns are closely related to notoungulates, another widespread group of South American ungulates. There were two major groups of litopterns: Proterotheriidae and Macraucheniidae. Proterotheriids were medium to large animals that evolved adaptations for fast running, and occupied a variety of niches that elsewhere were filled by animals such as goats and antelopes, mouse deer, and hors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole-body protein content. Collagen consists of amino acids bound together to form a triple helix of elongated fibril known as a collagen helix. It is mostly found in connective tissue such as cartilage, bones, tendons, ligaments, and skin. Depending upon the degree of mineralization, collagen tissues may be rigid (bone) or compliant (tendon) or have a gradient from rigid to compliant (cartilage). Collagen is also abundant in corneas, blood vessels, the gut, intervertebral discs, and the dentin in teeth. In muscle tissue, it serves as a major component of the endomysium. Collagen constitutes one to two percent of muscle tissue and accounts for 6% of the weight of the skeletal muscle tissue. The fibroblast is the most common cell tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megatherium
''Megatherium'' ( ; from Greek () 'great' + () 'beast') is an extinct genus of ground sloths endemic to South America that lived from the Early Pliocene through the end of the Pleistocene. It is best known for the elephant-sized type species ''M. americanum'', sometimes called the giant ground sloth, or the megathere, native to the Pampas through southern Bolivia during the Pleistocene. Various other smaller species belonging to the subgenus ''Pseudomegatherium'' are known from the Andes. ''Megatherium'' is part of the sloth family Megatheriidae, which also includes the similarly giant '' Eremotherium'', comparable in size to ''M. americanum,'' which was native to tropical South America, Central America and North America as far north as the southern United States. Only a few other land mammals equaled or exceeded ''M. americanum'' in size, such as large proboscideans (e.g., elephants) and the giant rhinoceros '' Paraceratherium''. ''Megatherium'' was first discovered in 178 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order (biology)
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. For some groups of organisms, their orders may follo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manatee
Manatees (family Trichechidae, genus ''Trichechus'') are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living species in the order Sirenia: the Amazonian manatee (''Trichechus inunguis''), the West Indian manatee (''Trichechus manatus''), and the West African manatee (''Trichechus senegalensis''). They measure up to long, weigh as much as , and have paddle-like tails. Manatees are herbivores and eat over 60 different freshwater and saltwater plants. Manatees inhabit the shallow, marshy coastal areas and rivers of the Caribbean Sea, the Gulf of Mexico, the Amazon basin, and West Africa. The main causes of death for manatees are human-related issues, such as habitat destruction and human objects. Their slow-moving, curious nature has led to violent collisions with propeller-driven boats and ships. Some manatees have been found with over 50 scars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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