Bugtirhinus
| Bugtirhinus | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Lower Miocene ( Burdigalium ) | ||||||||||||
| 20 to 18 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Bugtirhinus | ||||||||||||
| Antoine & Welcomme , 2000 | ||||||||||||
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Bugtirhinus is an extinct genus of rhinos . She livedin South Asia in the Lower Miocene 20 million years ago. It is a very small representative of this odd ungulate group and is the earliest member of the Elasmotherien, an extinct collateral line related to today's rhinos, which producedone of the largest known forms of rhinosin the Pleistocene with Elasmotherium .
features
Bugtirhinus was a small and slender representative of the rhinos, but so far only fossils of teeth and the musculoskeletal system have survived. Like the early representatives of the Elasmotherien, the rhinoceros genus also had incisors , but they are quite small. The lower outer tooth in particular had a typical sub-conical shape, which is also found in other Elasmotherien, and was at least 3.5 cm long. Of the posterior teeth, only the upper one is sufficiently known. This consists of the three posterior premolars and the molars . In general, the molars are clearly low-crowned ( brachyodont ) and small, with the tooth size increasing towards the back. The tooth crowns are rounded and not as angular as in later Elasmotheria, but already contain dental cement , which is much more common in the molars. The largest tooth in the dentition is the rearmost molar with a length of 3.4 cm, a width of 3.9 cm and a height of 3.4 cm.
The remaining finds include the musculoskeletal system, whereby only the foot is largely known. This consists of three rays with a more robust central ray ( metatarsus III), which is typical of rhinos. The traditional ankle bones are square, relatively small and slender. Only a fragmented radius has survived from the arm . Individual carpal bones and a metacarpus have been discovered from the hand . The shape of the hook bone (Unciform) indicates that a smaller fourth toe was still formed (Metacarpus V), so that the hand was constructed with four rays, as has also been demonstrated in other Elasmotheria. In contrast to other rhino lines, this additional finger was not lost here later.
Locations
Remains of Bugtirhinus were found in several places within the Dera-Bugti formation in the Bugti Mountains in Balochistan . Here they come from the fourth layer member (Bugti 4), which due to numerous African fauna elements is dated to the early Miocene ( Burdigalium , more precisely the lowest area of the MN 3 level, determined by the mammals of the Neogene ).
Systematics
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Internal systematics of the Elasmotheriini according to Sanisidro et al. 2012 and Deng 2008
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Bugtirhinus is an extinct representative of the rhinoceros family . Within this it is assigned to the tribe of the Elasmotheriini (Elasmotherien), which are also extinct and in turn represent a group in the subfamily of the Rhinocerotinae , which includes the modern rhinos. The sister group are the Rhinocerotini , to which the rhinos still alive today belong.
Within the Elasmotheria, Bugtirhinus represents the most primitive representative of this rhinoceros group to date, as shown by the small size, but also by the numerous archaic features, such as the four-pointed hand or the rounded crowns of the molars. The genus has no modern or derived characteristics compared to the later Elasmotheria. The closest related forms are Kenyatherium and Caementodon . Since both Caementodon and Bugtirhinus were widespread in South Asia , an origin of the Elasmotherien, which is to be assumed during the Oligocene , is assumed in this region. It was only around 18 million years ago that representatives of the Elasmotheria appeared, such as B. Hispanotherium in Europe . However, the spread must have been very rapid and probably took place during the second Proboscidean datum event 19 million years ago, as Kenyatherium and Ougandatherium, two very early Elasmotherias from Africa , have been described.
The first findings of Bugtirhinus were discovered at the beginning of the 20th century and described by Clive Forster-Cooper as Ceratorhinus in 1934 . Kurt Heissig later assigned them to the genus Caementodon . It was not until 2000 that it was described as a Bugtirhinus by Pierre-Olivier Antoine and Jean-Loup Welcomme . A right upper row of molars (M1 to M3) is the holotype (specimen number M 15361), which is kept in the Natural History Museum in London . The only recognized species is B. praecursor . The generic name Bugtirhinus refers on the one hand to the site in the Bugti Mountains, on the other hand rhinos is the genitive of the Greek word ῥίς ( rhīs "nose"). The species name praecursor is of Latin origin and means "forerunner", which indicates the position as the most original Elasmotherien representative.
Individual evidence
- ↑ a b c d e Pierre-Olivier Antoine and Jean-Loup Welcomme: A new rhinoceros from the lower miocene of the Bugti Hills, Baluchistan, Pakistan: the earliest elasmotheriine. Palaeontology 43 (5), 2000, pp. 795-816
- ↑ Pierre-Olivier Antoine, Francisco Alferez and Carlos lñigo: A new elasmotheriine (Mammalia, Rhinocerotidae) from the Early Miocene of Spain. Comptes Rendus Palevol 1, 2002, pp. 19-26
- ↑ Oscar Sanisidro, María Teresa Alberdi and 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
- ↑ Kurt Heissig and Oldřich Fejfar: The fossil rhinos (Mammalia, Rhinocerotidae) from the Lower Miocene of Tuchorice in northwestern Bohemia. Sborník Národního Muzea v Praze. Acta Musei Nationalis Pragae (series B, Natural History) 63 (1), 2007, pp. 19-64
- ^ Claude Guérin and Martin Pickford: Ougandatherium napakense nov. gen. nov. sp., le plus ancien Rhinocerotidae Iranotheriinae d'Afrique. Annales de Paléontologie 89, 2003, pp. 1-35