Ningxiatherium

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Ningxiatherium
Temporal occurrence
late Miocene
11 to 5? Million years
Locations
  • East Asia: northern China
Systematics
Higher mammals (Eutheria)
Laurasiatheria
Unpaired ungulate (Perissodactyla)
Rhinocerotoidea
Rhinoceros (Rhinocerotidae)
Ningxiatherium
Scientific name
Ningxiatherium
Chen , 1977
species
  • Ningxiatherium longirhinus Chen , 1977
  • Ningxiatherium euryrhinus Deng , 2008

Ningxiatherium is a now extinct genus of very large rhinos that lived about 11 million years ago in the Miocene in northern China. It belongs to the group of Elasmotheriini, which is generally characterized by its large body size and high crowns of the molars with partly clearly folded enamel and represents the closest related group to the rhinoceros species living today.

features

Representatives of Ningxiatherium were very large rhinos. The genus is known from two largely complete skulls and a few isolated teeth. The skull was elongated and narrow, reaching a length of 93 to 100 cm. The elongated and acute-angled occiput resulted in a relatively low head position. The nasal bone was rounded and had an ossified nasal septum in the front third . The forehead line between the nasal and occiput showed only a slight saddle. Rough, speckled surface structures on the top of the skull indicated the position of the horn, which was not on the forehead , as in the later Elasmotheria , but on the nasal bone. A forehead horn was not trained at Ningxiatherium . The position of the orbit was at the level of the end of the last molar and thus very far back in the skull.

The maxillary dentition was significantly reduced and consisted of at least three premolars and three molars, incisors and canines were not formed. But that made it a little more extensive than that of its later descendants, such as the Elasmotherium . The two rows of teeth were clearly parallel to each other. The anterior premolars were relatively small, while the last almost reached the dimensions of the following molar and was characteristically molarized. However, the largest was the second molar. As with all Elasmotheriini, the teeth were extremely high crowned ( hypsodontic ), but the tooth enamel did not yet show such strong folds.

Fossil finds

So far only a few sites are known, all of which are in northern China . A first skull was found in the 1970s in sandstone deposits of the Ganhegou Formation in the Ningxia Basin in the autonomous region of Ningxia and is also the evidence for the first description of the rhinoceros genus. Another complete skull comes from red-clay sediments of the Linxia- Basin in Dongxiang Autonomous County of Gansu Province and came to light in the early 21st century.

Systematics

Internal systematics of the Elasmotheriini according to Sanisidro et al. 2012 and Deng 2008
  Rhinocerotinae  

 Menoceratini


   
  Elasmotheriini  

 Bugtirhinus


   

 Kenyatherium


   

 Caementodon


   

 Hispanotherium


   

 Procoelodonta


   

 Huaqingtherium


   

 Iranotherium


   

 Ningxiatherium


   

 Parelasmotherium


   

 Sinotherium


   

 Elasmotherium










Template: Klade / Maintenance / 3

   

 Rhinocerotini




Template: Klade / Maintenance / Style

Ningxiatherium belongs to the tribe of the Elasmotheriini , which forms a subgroup of the Rhinocerotidae and the sister taxon of the Rhinocerotini , to which today's rhinos belong. Within the Elasmotheriini, its closest relative is Parelasmotherium , with which it forms a clade and is assigned to the lower tribus of the Iranotheriina due to the position of the horn on the nasal bone . It stands opposite that of Sinotherium and Elasmotherium , the Elasmotheriina. Some researchers also put Ningxiatherium directly to Parelasmotherium , but both show clear differences. So has Ningxiatherium a partially ossified nose, which at Parelasmotherium not occur. The occiput is also strongly drawn out and pointed in the former, while in the latter it is short and rectangular in shape.

Ningxiatherium developed in the late Miocene around 11 million years ago, probably from Parelasmotherium , which survived as the only representative of the Elasmotheriini in northern China after a cooler climatic phase due to which numerous rhinoceros became extinct. How long it lived is unclear, but it has not yet been proven in the Pliocene .

The first description was made by Chen Guafeng in 1977 based on the skull from the Ningxia Basin. According to the transcription of the time, it was written Ninxiatherium . Today two types are recognized:

  • Ningxiatherium longirhinus Chen , 1977
  • Ningxiatherium euryrhinus Deng , 2008

Both species differ largely in the shape of the nasal region, which is very long and narrow in N. longirhinus, but much shorter and broader in N. euryrhinus .

Individual evidence

  1. a b c d e f Deng Tao: A new elasmothere (Perissodactyla, Rhinocerotidae) from the late Miocene of the Linxia Basin in Gansu, China. Geobios 41, 2008, pp. 719-728
  2. Yupei Zhai and Tiliang Cai: The Tertiary system of Gansu Province. Gansu Geology 1984, pp. 1-40
  3. Deng Tao: The sequence of Cenozoic rhinocerotid fossils from the Linxia Basin (Gansu, China). In: L. Maul and RD Kahlke (Eds.): Late Neogene and Quaternary biodiversity and evolution: Regional developments and interregional correlations. Conference Volume. 18th International Senckenberg Conference. VI International Palaeontological Colloquium in Weimar. Conference in Weimar, 25. – 30. April, 2004. Terra Nostra, Writings of the Alfred Wegener Foundation (Berlin), 2004
  4. 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
  5. 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
  6. Esperanza Cerdeño: cladistic analysis of the Family Rhinocerotidae (Perissodactyla). American Museum Novitates 3143, 1995, pp. 1-25
  7. 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: 467-475
  8. Deng Tao: Evolution of Chinese Neogene Rhinocerotidae and Its Response to Climatic Variations. Acta Geologica Sinica 76 (2), 2002, pp. 139-145
  9. Chen Guanfeng: Ning Xia Zhongning rhinoceros fossils. Vertebrata Palasiatica 15 (2), 1977, pp. 143-147 (in Chinese)