Urtinotherium Temporal range: Eocene to Early Oligocene, | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Perissodactyla |
Family: | † Paraceratheriidae |
Genus: | † Urtinotherium Chow & Chiu, 1963 |
Species | |
Synonyms | |
Species synonyms
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Urtinotherium (meaning "Urtyn beast") is an extinct genus of paracerathere mammals. It was a large animal that was closely related to Paraceratherium , and found in rocks dating from the Late Eocene to Early Oligocene period. The remains were first discovered in the Urtyn Obo region (now Dorbod Banner, Ulanqab) in Inner Mongolia, which the name Urtinotherium is based upon. Other referred specimens are from northern China. [2]
Urtinotherium was a representative of the large family Paraceratheriidae, and almost reached the proportions of Paraceratherium . It is known from several findings in central and eastern Asia, though no complete skeletons are known. The holotype fossil (catalog number IVPP V.2769) includes a complete lower jaw 71.5 cm (28.1 in) in length, comparable to the smallest known of Paraceratherium. The jaw is wedge shaped, very low in height, and with elongated branches. The symphysis was solid and extended to the beginning of the second premolars. The jaw's dentition is complete, having three front incisors and canine. The first two incisors protrude forward with a crown length of 4.9 cm (1.9 in), with forms similar to daggers. The other incisors and canines had much smaller crowns. Between each tooth is a small space, similar to its phylogenetically primitive relatives such as Juxia . Its back teeth, which are separated from the front teeth by a small diastema, consist of four premolars and three molars. These are similar in structure to those of Paraceratherium, with small premolars and larger molars. The latter have low crowns (are brachyodont) and had few enamel folds. [3]
The remains of Urtinotherium are found mainly in the eastern and central Asia, consisting mostly of jaw fragments and isolated teeth. The holotype jaw was found in the early 1960s in the Urtyn-Obo Formation of Inner Mongolia, which dates from the Late Eocene. [3] Additional findings came from Yunnan province in China and Late Eocene deposits of Khoer-Dzam in Mongolia. Further findings have been made in Saissansee Aksyir Svita basin in eastern Kazakhstan, also of the same age. [2] Urtinotherium likely survived into the Early Oligocene, as fossils probably from it have been found in the Mera Formation of Transylvania, Romania. [4]
Urtinotherium pertains to the Paraceratheriidae subfamily Paraceratheriinae. These in turn are part of the superfamily Rhinocerotoidea and therefore represent close relatives of modern rhinoceroses. The paraceratheres are distinguished by the formation of large sharp incisors in their upper and lower jaws, while rhinoceroses only have a two on the lower jaw. Urtinotherium was thought of by Leonard Radinsky to be a transitional form between earlier paraceratheres, like Juxia, and later forms, such as Paraceratherium and Indricotherium (now Paraceratherium transouralicum). [5]
This genus represents a primitive form of paracerathere that developed in the late Eocene. It is possibly descended from Juxia, which lived during the Middle Eocene in northern China, and which shares with it having a full set of teeth in its jaws. However, Urtinotherium differs by its larger body size and greater specialization in the incisors. [6] Urtinotherium and later Paraceratherium form the most derived section of the largest known rhinocerotoid lineage. In their specialization emphasizes that compared to Urtinotherium, they possessed significantly reduced dentition with only a couple of incisors in the lower jaw. [7]
The first description of Urtinotherium was published in 1963 by Zhou Ming-Zhen and Chiu Chan-Siang, based on the lower jaw. The type species is recognized as Urtinotherium incisivum. The genus name comes from the location, and from the Ancient Greek word θηρίον (therion) meaning "beast". The species name refers to its elongated incisivos. [3]
Andrewsarchus is an extinct genus of mammal that lived during the Middle Eocene in China. It contains two species, A. mongoliensis and A. crassum. It was formerly placed in the families Mesonychidae or Arctocyonidae, but is now the sole member of a distinct family, Andrewsarchidae. It is most notable for being estimated as the largest terrestrial, carnivorous mammal, but that status has been disputed.
Paraceratherium is an extinct genus of hornless rhinocerotoids belonging to the family Paraceratheriidae. It is one of the largest terrestrial mammals that has ever existed and lived from the early to late Oligocene epoch. The first fossils were discovered in what is now Pakistan, and remains have been found across Eurasia between China and the Balkans. Paraceratherium means "near the hornless beast", in reference to Aceratherium, the genus in which the type species P. bugtiense was originally placed.
Amynodontidae is a family of extinct perissodactyls related to true rhinoceroses. They are commonly portrayed as semiaquatic hippo-like rhinos but this description only fits members of the Metamynodontini; other groups of amynodonts like the cadurcodontines had more typical ungulate proportions and convergently evolved a tapir-like proboscis.
Juxia, ‘joo-she-a’, is an extinct genus of paraceratheriid, a group of herbivorous mammals that are related to the modern rhinoceros. The type species is Juxia sharamurenensis, named by Zhou Mingzhen and Qiu Zhanxiang in 1964. Juxia was around the size of a horse. It lived in Asia during the upper Eocene.
Gobiconodon is an extinct genus of carnivorous mammals belonging to the family Gobiconodontidae. Undisputed records of Gobiconodon are restricted to the Early Cretaceous of Asia and North America, but isolated teeth attributed to the genus have also been described from formations in England and Morocco dating as far back as the Middle Jurassic. Species of Gobiconodon varied considerably in size, with G. ostromi, one of the larger species, being around the size of a modern Virginia opossum. Like other gobiconodontids, it possessed several speciations towards carnivory, such as shearing molariform teeth, large canine-like incisors and powerful jaw and forelimb musculature, indicating that it probably fed on vertebrate prey. Unusually among predatory mammals and other eutriconodonts, the lower canines were vestigial, with the first lower incisor pair having become massive and canine-like. Like the larger Repenomamus there might be some evidence of scavenging.
Tillodontia is an extinct suborder of eutherian mammals known from the Early Paleocene to Late Eocene of China, the Late Paleocene to Middle Eocene of North America where they display their maximum species diversity, the Middle Eocene of Pakistan, and the Early Eocene of Europe. Leaving no descendants, they are most closely related to the pantodonts, another extinct group. The tillodonts were medium- to large-sized animals that probably feed on roots and tubers in temperate to subtropical habitats.
Tapiroidea is a superfamily of perissodactyls which includes the modern tapirs and their extinct relatives.
Brachyhyops is an extinct genus of entelodont artiodactyl mammal that lived during the Eocene Epoch of western North America and southeastern Asia. The first fossil remains of Brachyhyops are recorded from the late Eocene deposits of Beaver Divide in central Wyoming and discovered by paleontology crews from the Carnegie Museum of Natural History during the early 20th century. The type species, Brachyhyops wyomingensis, is based on a single skull and was named by E.H. Colbert in 1937, but was not officially described until 1938. During the latter half of the 20th century, additional specimens from North America have been recorded from Saskatchewan and as far south as Texas, indicating that Brachyhyops had a broad distribution and was well-dispersed throughout western North America.
The Irdin Manha Formation is a geological formation from the Eocene located in Inner Mongolia, China, a few kilometres south of the Mongolian border.
Homogalax is an extinct genus of tapir-like odd-toed ungulate. It was described on the basis of several fossil finds from the northwest of the United States, whereby the majority of the remains come from the state of Wyoming. The finds date to the Lower Eocene between 56 and 48 million years ago. In general, Homogalax was very small, only reaching the weight of today's peccaries, with a maximum of 15 kg. Phylogenetic analysis suggests the genus to be a basal member of the clade that includes today's rhinoceros and tapirs. In contrast to these, Homogalax was adapted to fast locomotion.
Coryphodontidae is an extinct family of pantodont mammals known from the Late Paleocene to the Middle Eocene of Eurasia and North America.
Eggysodon is an extinct genus of odd-toed ungulate belong to the rhinoceros-like family Eggysodontidae. It was a small, ground-dwelling browser, and fossils have been found in Oligocene deposits throughout Europe. Eggysodon may have been related to Preaceratherium, and both had tusklike canines and smaller, and fewer, incisors.
Eggysodontidae is a family of perissodactyls closely related to rhinoceroses. Fossils have been found in Oligocene deposits in Europe, the Caucasus, Central Asia, China, and Mongolia.
Forstercooperia is an extinct genus of forstercooperiine paraceratheriid rhinoceros from the Middle Eocene of Asia.
Ronzotherium is an extinct genus of perissodactyl mammal from the family Rhinocerotidae. The name derives from the hill of 'Ronzon', the French locality near Le Puy-en-Velay at which it was first discovered, and the Greek suffix 'therium' meaning 'beast'. At present 5 species have been identified from several localities in Europe and Asia, spanning the Late Eocene to Upper Oligocene.
Pappaceras is an extinct genus of rhinoceros from the Early Eocene of Asia belonging to Paraceratheriidae.
Allacerops is an extinct genus of odd-toed ungulate belong to the rhinoceros-like family Eggysodontidae. It was a small, ground-dwelling browser, and fossils have been found in Oligocene deposits throughout Central and East Asia.
Dzungariotherium is a genus of paraceratheriid, an extinct group of large, hornless rhinos, which lived during the middle and late Oligocene of northwest China. The type species D. orgosense was described in 1973 based on fossils—mainly teeth—from Dzungaria in Xinjiang, northwest China.
Azygonyx was a small tillodont mammal, likely the size of a cat to raccoon, that lived in North America during the Paleocene and Eocene in the early part of the Cenozoic Era. The only fossils that have been recovered are from the Willwood and Fort Union Formations in the Bighorn Basin of Wyoming, United States, and date to the Clarkforkian to Wasatchian, about 56 to 50 million years ago. Fifty-six collections that have been recovered thus far include the remains of Azygonyx. Azygonyx survived the Paleocene Eocene Thermal Maximum along with other mammals like Phenacodus and Ectocion, both of which were ground-dwelling mammals. Azygonyx probably was a generalist terrestrial mammal that may have roamed around the ground, but was also capable of climbing trees.
Martinmiguelia is an extinct genus of Notoungulate, belonging to the family Leontiniidae. It lived during the Middle Eocene, and its fossil remains were found in South America.