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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 uncertain. Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxodontia
Toxodontia. Retrieved April 2013. is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The group is named after ''Toxodon'', the first example of the group to be discovered by science. Description Isotemnidae, the oldest and most primitive family of toxodonts, were generally large animals with larger canines than other early notoungulates. The family is probably paraphyletic or polyphyletic since only primitive dental features unite the 12 included genera, such as a complete dentition with unreduced canines and no diastemata in the earliest genera. Likewise, they are only weakly linked to other toxodonts by a few dental features, and their primitive cheek tooth pattern can be basal to all notoungulates except notioprogonians. The oldest of the 12 genera in this family is ''Isotemnus'' known from the Riochican-Casamayoran, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxodonta
Toxodontia. Retrieved April 2013. is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The group is named after ''Toxodon'', the first example of the group to be discovered by science. Description Isotemnidae, the oldest and most primitive family of toxodonts, were generally large animals with larger canines than other early notoungulates. The family is probably paraphyletic or polyphyletic since only primitive dental features unite the 12 included genera, such as a complete dentition with unreduced canines and no diastemata in the earliest genera. Likewise, they are only weakly linked to other toxodonts by a few dental features, and their primitive cheek tooth pattern can be basal to all notoungulates except notioprogonians. The oldest of the 12 genera in this family is ''Isotemnus'' known from the Riochican-Casamayoran, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litopterna
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 horses. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachyrukhos
''Pachyrukhos'' is an extinct genus of hegetotheriid notoungulate from the Early to Middle Miocene (Colhuehuapian-Friasian in the SALMA classification) of Argentina and Chile. Fossils of this genus have been found in the Collón Curá, Sarmiento and Santa Cruz Formations of Argentina and the Río Frías Formation of Chile.''Pachyrukhos'' at .org Description It was about long and closely resembled a , with a short tail and long hind feet. ''Pachyrukhos'' was probably also able to hop, and it had a rabbit-like |
Henricosborniidae
Henricosborniidae is a family of extinct notoungulate mammals known from the Late Paleocene to Middle Eocene of Argentina, Bolivia and Brazil. The name honors U.S. paleontologist Henry Fairfield Osborn. Description Henricosborniidae is a group of primitive notoungulates assigned to the suborder Notioprogonia together with Notostylopidae, not because these two families share any derived features, but because they do not clearly belong to any other clade. The henricosborniids are only known from the late Paleocene and early Eocene (Itaboraian-Casamayoran SALMA, ), making them slightly older and more primitive than the notostylopids. The henricosborniid dentition is the most generalized and primitive of all notoungulates, and they are believed to be near the source of all notoungulates. They have low teeth crowns and the dental formula . George Gaylord Simpson noted that many of the mammals that Ameghino had, and Simpson himself did, describe from the Río Chico Formation, on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odd-toed Ungulate
Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (, ), are animals—ungulates—who have reduced the weight-bearing toes to three (rhinoceroses and tapirs, with tapirs still using four toes on the front legs) or one (equines, third toe) of the five original toes. The non-weight-bearing toes are either present, absent, vestigial, or positioned posteriorly. By contrast, the even-toed ungulates bear most of their weight equally on four or two (an even number) of the five toes: their third and fourth toes. Another difference between the two is that odd-toed ungulates digest plant cellulose in their intestines rather than in one or more stomach chambers as even-toed ungulates, with the exception of Suina, do. The order includes about 17 species divided into three families: Equidae (horses, asses, and zebras), Rhinocerotidae (rhinoceroses), and Tapiridae (tapirs). Despite their very different appearances, they were recognized as related families in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hares
Hares and jackrabbits are mammals belonging to the genus ''Lepus''. They are herbivores, and live solitarily or in pairs. They nest in slight depressions called forms, and their young are able to fend for themselves shortly after birth. The genus includes the largest lagomorphs. Most are fast runners with long, powerful hind legs, and large ears to dissipate body heat. Hare species are native to Africa, Eurasia and North America. A hare less than one year old is called a "leveret". A group of hares is called a "husk", a "down" or a "drove". Members of the ''Lepus'' genus are considered true hares, distinguishing them from rabbits which make up the rest of the Leporidae family. However, there are five leporid species with "hare" in their common names which are not considered true hares: the hispid hare (''Caprolagus hispidus''), and four species known as red rock hares (comprising ''Pronolagus''). Conversely, several ''Lepus'' species are called "jackrabbits", but classed as har ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rabbits
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit species and its descendants, the world's 305 breeds of domestic rabbit. ''Sylvilagus'' includes 13 wild rabbit species, among them the seven types of cottontail. The European rabbit, which has been introduced on every continent except Antarctica, is familiar throughout the world as a wild prey animal and as a domesticated form of livestock and pet. With its widespread effect on ecologies and cultures, the rabbit is, in many areas of the world, a part of daily life—as food, clothing, a companion, and a source of artistic inspiration. Although once considered rodents, lagomorphs like rabbits have been discovered to have diverged separately and earlier than their rodent cousins and have a number of traits rodents lack, like two extra incisor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyly
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic group (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term was coined by Willi Hennig to apply to well-known taxa like Reptilia ( reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor, including all extant reptiles as well as the extinct synapsids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notostylopidae
Notostylopidae is an extinct family comprising five genera of notoungulate mammals known from the Late Paleocene (Riochican) to Early Oligocene (Tinguirirican) of Argentina, Brazil and Chile in South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...McKenna, Malcolm C., and Bell, Susan K. 1997. ''Classification of Mammals Above the Species Level.'' Columbia University Press, New York, 631 pp. References Notoungulates Prehistoric mammal families Paleogene mammals of South America Eocene first appearances Rupelian extinctions Taxa named by Florentino Ameghino {{paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomashuxleya
''Thomashuxleya'' is an extinct genus of notoungulate mammal, named after famous 19th-century biologist Thomas Huxley. Description ''Thomashuxleya'' was about in length and weighted an estimated , with a heavy body and strong limbs.D. Patterson, Bruce (€2012) ''Bones, Clones, and Biomes: The History and Geography of Recent Neotropical Mammals'' p.83 Its large skull had 44 teeth in its jaws, including large canines which may have been used to dig around in earth. It had four toes on each foot, and probably walked somewhat like a modern peccary. It was a relatively generalised animal, not specialised for any particular way of life. There's an almost complete skeleton of this animal in exhibition in the American Museum of Natural History. This skeleton was discovered during the Scarrit expedition to Patagonia, Argentina, that was led by the paleontologist George Gaylord Simpson. Fossils of ''Thomashuxleya'' have been found in the Sarmiento and Casamayor Formations of Argentina. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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