Parelasmotherium
| Parelasmotherium | ||||||||||||
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| Temporal occurrence | ||||||||||||
| late Miocene | ||||||||||||
| 11 to 5? Million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Parelasmotherium | ||||||||||||
| Killgus , 1923 | ||||||||||||
Parelasmotherium is an extinct genus of rhinos thatlivedin northern China about 11 million years ago inthe late Miocene . It belonged to his great physique and his teeth hochkronigen to the group of Elasmotheriini and was thus a relative of the Pleistocene over much of northern Asia spread Elasmotherium .
features
Parelasmotherium was a large representative of the rhinoceros, but so far it is largely only known from isolated teeth, individual skeletal elements of the musculoskeletal system and from a complete, but laterally slightly pressed skull. At 97 cm, it was extremely elongated and very narrow. The occiput was slightly pulled out and rather rectangular in shape and had a clear, straight bulge when viewed from above as a starting point for the neck muscles. The elongated nasal bone was sturdy and was clearly rounded in the front part. In contrast to later Elasmotheria, the nasal septum did not yet have any ossified structures. Pearl-shaped roughening on the surface of the nasal bone marked the point of attachment for the horn, which, however, did not sit directly on the tip of the nose, but rather in the middle area of the nasal bone. A forehead horn as in Elasmotherium was not developed. The eye socket was above behind the last molar .
As with all Elasmotheriini, the maxillary dentition was characterized by a significant reduction in the front teeth, so that the incisors and the canines were missing. The posterior teeth consisted of three premolars and three molars, and the deciduous dentition also contained the anterior premolar. The premolars were smaller than the molars, but were similar in structure. In general, the teeth had very high crowns , the second molar, which was also the largest tooth in the dentition, was up to 13 cm high. The values for the height of the molars were above those of the length and thus refer to the later representatives of the Elasmotheria with their even higher tooth crowns, while the height values of the earlier genera did not reach those of the length. In addition, they had a high proportion of cement and clearly folded enamel , which, however, did not yet have such distinctive curves as in the later Elasmotherium . The high tooth crowns and the structure of the teeth suggest that Parelasmotherium was a specialized grass eater ( grazer ), which corresponds to the climatic changes and associated landscape changes in the form of the spread of open steppes that occurred in the late Miocene .
Fossil finds
Finds of Parelasmotherium are rare and so far only come from northern China . The finds of the type specimen come from Kutschwuan in the Chinese province of Shanxi and include a jaw fragment with preserved rear teeth as well as several long and foot bones. Other finds come from Guonigou in the Linxia Basin in the Gansu Province . These include numerous isolated teeth, but an almost complete skull was also discovered there in the early 21st century. Various finds also come to light in pharmacies for traditional Chinese medicine .
Systematics
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Internal systematics of the Elasmotheriini according to Sanisidro et al. 2012 and Deng 2008
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Parelasmotherium belongs to the tribe of Elasmotheriini , a group of very large rhinos with very high-crowned molars, which are the closest relatives of the Rhinocerotini to the rhinoceros species still alive today. Within the Elasmotheriini the genus forms a clade with Ningxiatherium . Both rhinoceros forms, together with the Iranotherium standing further out, are assigned to the sub-tribus Iranotheriina due to the position of their horn on the nose and the generally not quite as high-crowned molars and less folded tooth enamel, which are the tribal historically younger forehead horn-bearing and extremely high-crowned modern Elasmotheiina, to which also the known Elasmotherium belongs to face. Some researchers also placed Ningxiatherium in the genus Parelasmotherium , but with the discovery of the first complete Parelasmotherium skull at the beginning of the 21st century, clear differences between the two genera became apparent, among other things in the lack of ossification of the front part of the nasal septum and the differently built occipital bone exist in Parelasmotherium .
The genus Parelasmotherium was first described by H. Killgus 1923 described . The finds from Kutschwuan in Shanxi served as a holotype . T. Ringström, who in 1922 had described another representative of the Elasmotheriina with Sinotherium , saw no major differences to this and equated Parelasmotherium with Sinotherium . Subsequent analyzes showed clear differences in the tooth structure and crown height of the two genera, which were later not only confirmed by the first skull find, but also expanded. Furthermore, Sinotherium was generally larger than Parelasmotherium .
Three recognized species have been described so far:
- Parelasmotherium schansiense Killgus , 1923
- Parelasmotherium simplum ( Chow , 1958)
- Parelasmotherium linxiaense Deng , 2001
Individual evidence
- ↑ a b c d e f Deng, Tao: Skull of Parelasmotherium (Perissodactyla, Rhinocerotidae) from the Upper Miocene in the Linxia Basin (Gansu, China). Journal of Vertebrate Paleontology 27 (2), 2007, pp. 467-47
- ↑ a b c d Qiu Zhanxiang and Xie Junyi: Notes on Parelasmotherium and hipparion fossils from Wangji, Dongxiang, Gansu. Vertebrata Palasiatica 36 (1), 1998, pp. 13-23
- ↑ Deng Tao: Evolution of Chinese Neogene Rhinocerotidae and Its Response to Climatic Variations. Acta Geologica Sinica 76 (2), 2002, pp. 139-145
- ↑ Deng Tao: New remains of Parelasmotherium (Perissodactyla, Rhinocerotidae) from the Late Miocene in Dongxiang, Gansu, China. Vertebrata Palasiatica 39 (4), 2001, pp. 306-311
- ↑ Oscar Sanisidro, María Teresa Alberdi, Jorge Morales: The First Complete Skull of Hispanotherium matritense (Prado, 1864) (Perissodactyla, Rhinocerotidae) from the Middle Miocene of the Iberian Peninsula. Journal of Vertebrate Paleontology, 32 (2), 2012, pp. 446-455
- ↑ Tao Deng: A new elasmothere (Perissodactyla, Rhinocerotidae) from the late Miocene of the Linxia Basin in Gansu, China. Geobios 41, 2008, pp. 719-728
- ↑ Pierre-Okivier Antoine: Middle Miocene elasmotheriine Rhinocerotidae from China and Mongolia: taxonomic revision and phylogenetic relationships. The Norwegian Academy of Science and Letters - Zoologica Scripta 32, 2003, pp. 95-118
- ↑ Esperanza Cerdeño: cladistic analysis of the Family Rhinocerotidae (Perissodactyla). American Museum Novitates 3143, 1995, pp. 1-25