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Hegetotheriidae
Hegetotheriidae is an extinct family of notoungulate mammals known from the Oligocene through the Pliocene of 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 .... References Typotheres Oligocene mammals Miocene mammals of South America Pliocene mammals Pliocene extinctions Pliocene notoungulates Prehistoric mammal families {{paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremacyllus
''Tremacyllus'' is an extinct genus of hegetotheriids. It lived from the Late Miocene to the Late Pleistocene (~7-0.012 Ma) and its fossilized remains were discovered in South America. Description This animal was approximately the size of a hare, and both animals, while unrelated, must have been quite similar in appearance. Its skull had large orbits and strong lower incisors, similar to modern lagomorphs. It was probably a fast animal, with long legs, although proportionally shorter than other similar animals such as ''Pachyrukhos'' or extant lagomorphs. Compared to its relative ''Paedotherium'', ''Tremacyllus'' was slightly smaller and possessed several distinctive characteristics in its dentition: its diastema was longer, the third upper molar was shorter or had the same size than the second molar, and the lower premolars were more overlapping and less molar-like. Furthermore, the symphysis of the mandible was shorter than in ''Paedotherium''. Classification The genus ''Tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paedotherium
''Paedotherium'' is an extinct, potentially paraphyletic genus of Notoungulate, belonging to the family Hegetotheriidae, composed of small-sized, rodent or lagomorph-like Meridiungulata, South American ungulates. Four species are unambiguously recognized, from the Late Miocene to the Pleistocene of Argentina, and from the late Miocene of Bolivia and Chile. History The first remains associated today with ''Paedotherium'' were first described in 1887 by Florentino Ameghino, and attributed to the related genus ''Pachyruckhos'' due to an important number of similarities. He name the remains ''Pachyrukhos bonaerense''. Its holotype is MACN 1184, remains of the palatal area including the incisors, molars and premolars, to which he include another specimen, MACN 1667, both assumed to come from the Ensenada Formation. In 1888 Hermann Burmeister describe the new genus ''Paedotherium'' insigne. It is, however, rapidly considered a synonym of ''Pachyrukhos'', which take precedence and to ... [...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] |
Propachyrucos
''Propachyrucos'' is an extinct genus of hegetotheriid notoungulate. It lived from the Late Oligocene to the Early Miocene, in what is today South America. Description This animal was the size of a large hare, with a 10 centimeter long skull. Its body was slender, with a very short tail and strong forelegs, although much shorter than the hind legs, equipped with long metatarsals. The skull had a complete dentition, but the second and third incisors, as well as the canines and the first lower premolars, were vestigial. The first upper incisors were very large, and showed a considerable development. The molars had two internal folds separated by a further deep fold, like the Interatheriidae ; dental cementum was present, but to a lesser extent than in ''Interatherium''. The lower teeth were flat on the outside and bilobed on the inside. The tibia and fibula were not fused, and the forearm and lower leg bones were respectively shorter than the humerus and femur, but the hind legs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hegetotherium
''Hegetotherium'' is an extinct genus of mammals from the Early to Middle Miocene (Colhuehuapian-Colloncuran in the SALMA classification) of South America. Fossils of this genus have been found in the Cerro Bandera, Cerro Boleadoras, Chichinales, Collón Curá, Santa Cruz and Sarmiento Formations of Argentina, the Nazareno Formation of Bolivia, and the Galera and Río Frías Formations of Chile. Taxonomy ''Hegetotherium'' is currently restricted to the type species, ''H. mirable'', of which ''H. convexum'', ''H. anceps'', ''H. minum'' and ''H. andinum'' are synonyms, but also ''H. cerdasensis''. ''"Hegetotherium" arctum'' was formerly assigned to this genus, but is clearly not a member of Hegetotheriidae. ''"Hegetotherium" novum'' was formerly referred to the closely related genus ''Prohegetotherium ''Prohegetotherium'' is an extinct genus of Hegetotheriidae, hegetotheriid Notoungulata, notoungulates from the Oligocene, Late Oligocene to Miocene, Early Miocene (Deseadan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemihegetotherium
''Hemihegetotherium'' is an extinct genus of hegetotheriid notoungulate that lived from the Middle to the Late Miocene of what is now Argentina. Description It was a medium-sized animal, approximately the size of large lowland paca ; it may have reached a length of approximately one meter, and the larger species, such as ''Hemihegetotherium achataleptum'', could reach a weight of 20 kilograms. ''Hemihegetotherium'' had long legs, although not as those of modern lagomorphs, to which it was, in other regards, superficially similar. Like some of its relatives, the first pair of incisors of ''Hemihegetotherium'' was large, and it had simplified but high-crowned (hypsodont) molars and premolars. The structure of those teeth were so simplified in ''Hemihegetotherium'' that they consisted of simply a curved cylinder of enamel filled with dentin ; compared to ''Hegetotherium'', the molars were more convex, with a semi-elliptical section. However, those teeth had pointed cusps along th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prosotherium
''Prosotherium'' is an extinct genus of hegetotheriid notoungulate. It lived during the Late Oligocene (between ~29-24 Ma), and its fossilized remains were found in South America. Description This animal was similar to rabbits, in aspect and in size. Its hind legs were particularly long. Crania Its crania was light and thin, notably in the posterior part. The tympanic part of the temporal bone was particularly developed, even more than its relative ''Pachyrukhos'', and it is probable that its auricle was quite large, similar to the ears of a hare. The maxilla and the mandible were high and deep ; the mandible had a subtle coronoid process. The teeth were characterized by incisors pointing inward, molars and premolars covered by a thin layer of dental cementum, generally on the outside part of the upper teeth and on the inside part of the lower teeth. Postcranial skeleton The humerus was large and thin, like the ulna and radius. Metacarpals and phalanges indicates that the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethegotherium
''Ethegotherium'' is an extinct genus of Notoungulates, belonging to the suborder Typotheria. It lived from the Lower to the Middle Miocene, and its fossilized remains were discovered in South America. It might be a synonym of the genus ''Prohegetotherium''. Description This was a small-sized animal, not exceeding the size of a European rabbit. ''Ethegotherium'' is only known from a skull and a mandible, and it is difficult to restore its complete appearance. From comparison with its relatives, it can be supposed that it was a small notoungulate with a short tail and long hind legs. It shared similarities with the slightly older ''Prohegetotherium'', but differed from it in several ways, including its smaller size. The incisors and canines were directed forward, giving rise to a "false diastema" between them and the backward-directed first premolars. The upper canine had an arched crown, while the upper jugal teeth, with a high crown, were slightly imbricated, without any deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hegetotheriinae
Hegetotheriidae is an extinct family of notoungulate mammals known from the Oligocene through the Pliocene of 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 .... References Typotheres Oligocene mammals Miocene mammals of South America Pliocene mammals Pliocene extinctions Pliocene notoungulates Prehistoric mammal families {{paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachyrukhinae
Hegetotheriidae is an extinct family of notoungulate mammals known from the Oligocene through the Pliocene of 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 .... References Typotheres Oligocene mammals Miocene mammals of South America Pliocene mammals Pliocene extinctions Pliocene notoungulates Prehistoric mammal families {{paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typotheres
Typotheria is a suborder of the extinct mammalian order Notoungulata and includes five families: Archaeopithecidae, Campanorcidae, Interatheriidae, Mesotheriidae, and Oldfieldthomasiidae. CifelliCifelli, Richard L. 1993. The phylogeny of the native South American ungulates. pp. 195-216 ''in'' F. S. Szalay, M. J. Novacek and M. C. McKenna (''eds.'') ''Mammal Phylogeny, Volume 2, Placentals''. Springer-Verlag, New York. indicated that Typotheria would be paraphyletic if it excluded members of the suborder Hegetotheria and he advocated inclusion of the hegetothere families Archaeohyracidae and Hegetotheriidae Hegetotheriidae is an extinct family of notoungulate mammals known from the Oligocene through the Pliocene of South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a r ... in Typotheria. References Prehistoric animal suborders Mammal suborders {{paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medistylus
''Medistylus'' is an extinct genus of pachyrukhine hegetotheriid. It lived in Argentina during the Late Oligocene. ''Medistylus'' is known from its upper teeth and isolated skulls, however, its lower dentition is currently unknown. Its fossilized remains were found at the Cabeza Blanca and Las Cascadas localities of the Sarmiento Formation in Chubut Province of Argentina. Description ''Medistylus'' was one of the largest members of the subfamily Pachyrukhinae and had continuously growing teeth, like ''Propachyrucos''. It had a huge pair of front incisors, set obliquely. It lacked the teeth between the first incisor and the second molar, and instead had a toothless space, known as a diastema A diastema (plural diastemata, from Greek διάστημα, space) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition .... It fed on low-lying grass, which caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
