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Mesotheriidae
Mesotheriidae ("Middle Beasts") is an extinct family of notoungulate mammals known from the Oligocene through the Pleistocene of South America. Mesotheriids were small to medium-sized herbivorous mammals adapted for digging. Characteristics Mesotheriids were small to medium-sized notoungulates; larger forms were approximately the size of a sheep. Shockey et al., 2007 Additionally, the family is characterized by specializations of the teeth and skeleton. In the dentition, all mesotheriids have ever-growing incisors with enamel restricted to the anterior surface, a condition termed gliriform, as it also occurs in Glires (rodents and lagomorphs). The cheek teeth (premolars and molars) of mesotheriids are high-crowned (hypsodont) and in advanced members of the family, the cheek teeth are also ever-growing. Mesotheriid skeletons are heavily built and show features associated with digging in living mammals. In particular, fossorial characteristics of mesotheriids include deeply fissu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesotheriinae
Mesotheriidae ("Middle Beasts") is an extinct family of notoungulate mammals known from the Oligocene through the Pleistocene of South America. Mesotheriids were small to medium-sized herbivorous mammals adapted for digging. Characteristics Mesotheriids were small to medium-sized notoungulates; larger forms were approximately the size of a sheep. Shockey et al., 2007 Additionally, the family is characterized by specializations of the teeth and skeleton. In the dentition, all mesotheriids have ever-growing incisors with enamel restricted to the anterior surface, a condition termed gliriform, as it also occurs in Glires (rodents and lagomorphs). The cheek teeth ( premolars and molars) of mesotheriids are high-crowned (hypsodont) and in advanced members of the family, the cheek teeth are also ever-growing. Mesotheriid skeletons are heavily built and show features associated with digging in living mammals. In particular, fossorial characteristics of mesotheriids include deeply ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesotherium
''Mesotherium'' ("Middle Beast") is an extinct genus of mesotheriid, a long-lasting family of superficially rodent-like, burrowing notoungulates from South America. It one of the youngest notoungulates, and the last known member of Typotheria. It was first named by Étienne Serres in 1867, and through further finds now contains four species, ''M. cristatum'', ''M. hystatum'', ''M. maendrum'', and ''M. pachygnathum''. Fossils have been found in Argentina, dating to the Early-Middle Pleistocene. Etymology Serres named ''Mesotherium'' so due to his belief that it was an intermediate between rodents and pachyderms (or ungulates), due to its large upper incisors, and its size and proportions. "Serres—by a happy inspiration proposed calling it Mesotherium—as being a common centre towards which all mammalia got happily confounded," Hugh Falconer wrote Darwin in April 1863. "Bravard sent it home under the name of Typotherium as being the central type from which all mammals diverged ... [...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 uncertain. Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trachytherus
''Trachytherus'' is an extinct genus of mesotheriid notoungulate that lived from the Late Oligocene to the Early Miocene in what is now South America. Description ''Trachytherus'' had a relatively low, compact skull with an elongated snout, longer than in ''Mesotherium'' but very similar. The postorbital process was also smaller and the nasal bones did not extend as far as in ''Mesotherium''. The most notable difference between the two genera was in the zygomatic arch ; in the anterior region, the insertion surface of the lateral masseter was highly developed, but not as large than in ''Mesotherium''. The first upper incisor was highly developed, continuously growing (hypsodont) and arched, with an enamel band only on the labial side. The following incisors, canines and premolars were greatly reduced or vestigial. The last three premolars were molar-like, with a very complex pattern rapidly disappearing with wear. The molars were similar to those of '' Pseudotypotherium'' and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiotypotherium
''Plesiotypotherium'' is an extinct genus of Notoungulate, belonging to the suborder Typotheria. It lived from the Middle to the Late Miocene, and its fossilized remains were discovered in South America. Description This animal was somewhat similar to modern wombats, but was slightly larger-sized. ''Plesiotypotherium'', like its relatives ''Trachytherus'' and ''Mesotherium'', was characterized by a postcranial skeleton suited for burrowing. Its scapula was characterized by a distally located suprascapular fossa; the deltoid crest was well developed. The humerus of ''Plesiotypotherium'' was slightly thinner than in ''Trachytherus'', and had a characteristic perforation in the olecranon fossa. The entepicondyle, ectepicondyle and supracondylar crest were well developed. The ulna was characterized by a well developed olecranon, while in the proximal area of the radius a sesamoid bone was articulated with the main bone; the distal part of the radius had particular grooves for the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiandraia
''Fiandraia'' is an extinct monotypic genus of notoungulate that lived in Uruguay during the Oligocene and the Early Miocene. It was found in the Fray Bentos Formation, in rocks dated back from the Deseadan period. The taxonomic status of ''Fiandraia'' has been historically disputed; in 1976, its discoverer, Roselli, assigned it in the family Mesotheriidae; in 1978, in Mones & Ubilla, it was considered part of Interatheriidae; McKenna & Bell, in 1997, placed it inside its own family, Fiandraiinae, itself part of Mesotheriidae; Flynn ''et al'' considered it, in 2005, as a member of the Toxodontidae instead of the Mesotheriinae Mesotheriidae ("Middle Beasts") is an extinct family of notoungulate mammals known from the Oligocene through the Pleistocene of South America. Mesotheriids were small to medium-sized herbivorous mammals adapted for digging. Characteristics M .... References Notoungulates Prehistoric placental genera Oligocene mammals of South America ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typotheriopsis
''Typotheriopsis'' is an extinct genus of Notoungulate, belonging to the family Mesotheriidae, which included several small sized Meridiungulates specialized in digging. It is considered as the sister taxon of the clade including ''Mesotherium'' and ''Pseudotypotherium''. Its fossils are known from the Chasicoan and the Huayquerian periods, notably among Late Miocene rocks from the Arroyo Chasicó Formation and the Cerro Azul Formation of Argentina. Description ''Typotheriopsis chasicoensis'' was described in 1931 by Angel Cabrera and Jorge L. Kraglievich, with a holotype composed of badly preserved cranial remains from the Arroyo Chasicó Formation of Argentina. Those remains were similar to ''Pseudotypotherium'', but included thicker teeth and less atrophied incisors than in other genera of mesotherid. Later studies expanded this list of differences between ''Typotheriopsis'' and ''Pseudotypotherium''. It was large for a mesothere, with a broad skull, and a suborbital foss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudotypotherium
''Pseudotypotherium'' is an extinct genus of Notoungulates, belonging to the suborder Typotheria. It lived from the Late Miocene to the Late Pliocene, and its fossilized remains were discovered in South America. Description This animal, like all the typotheres, was superficially similar to a rodent. It was close to the size of a sheep, and ''Pseudotypotherium'' is considered as one of the largest known Typotheres. It is known from several skeletons and skulls, and it is therefore possible to reconstruct faithfully its appearance. Classification The genus ''Pseudotypotherium'' was first described in 1904 by Florentino Ameghino, based on fossil remains found in Argentina in Late Pliocene terrains. Among the best known species is the type species ''P. pulchrum'', from the Late Pliocene, and the older species ''P. subinsigne'' and ''P. carhuense'' from the Late Miocene. Fossils attributed to the genus have also been found in Bolivia. ''Pseudotypotherium'' was a typical member o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsitherium
''Hypsitherium'' is an extinct genus of Mesotheriidae Mesotheriidae ("Middle Beasts") is an extinct family of notoungulate mammals known from the Oligocene through the Pleistocene of South America. Mesotheriids were small to medium-sized herbivorous mammals adapted for digging. Characteristics M ... that lived 4.0 to 3 million years ago, and is known from the Miocene to Pliocene Inchasi fossil locality in Bolivia. It was a scansorial herbivore, with its name meaning "high beast." References Further reading * B. J. MacFadden, F. Anaya, and J. Argollo. 1993. Magnetic polarity stratigraphy of Inchasi: a Pliocene mammal-bearing locality from the Bolivian Andes deposited just before the Great American Interchange. Earth and Planetary Science Letters 114(2-3):229-241 Typotheres Prehistoric placental genera Miocene mammals of South America Pliocene mammals of South America Chapadmalalan Neogene Bolivia Fossils of Bolivia Fossil taxa described in 1995 {{pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eotypotherium
''Eotypotherium'' is an extinct genus of mammal, belonging to the suborder Typotheria. It lived during the Early Miocene. Its fossilized remains were discovered in the Chucal Formation, in the Chilean altiplano, near the Salar de Surire, in South America. Etymology The name ''Eotypotherium'' is composed of the greek prefix "''Eo-''", meaning "dawn", and of the suffix "''-typotherium''", an invalid name for the genus ''Mesotherium'', which gave its name to the suborder Typotheria. This name was given due to the relative antiquity of this taxon compared to other Mesotheriidae. Description The genus is known from various remains of small-sized skulls, with the notable absence of a well-developed zygomatic plate. The first upper incisor presents a groove in its lingual part. Holotype The holotype, SGOPV 5157, held by the Chilean National Museum of Natural History in Santiago de Chile Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altitypotherium
''Altitypotherium'' is an extinct genus of Notoungulate, belonging to the suborder Typotheria. It lived during the Early Miocene, and its fossilized remains were discovered in South America. Description This animal was vaguely similar to a wombat, and its dimensions evocate those of a raccoon ; its skull was approximately 16 centimeters long, while its total length, excluding the tail, was about 80 centimeters. It weighed around 10 kilograms. ''Altitypotherium'' had a tall and narrow snout, with only six pairs of teeth in the maxilla and mandible, a low number when compared to most other notoungulates. It had gliriform upper incisors, with a band of anterior enamel, and lower incisors protruding forward and separated from premolars and molars by a long diastema. It had high-crowned (hypsodont) teeth, and the occlusal surfaces of the molars had two enamel folds halfway through the tooth in the inner surface and outlining three dentin-filled lobes, forming an E-shaped form. The l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Enamel
Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The other major tissues are dentin, cementum, and Pulp (tooth), dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. Calcium hardens the tooth enamel. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
