Punjabitherium

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Punjabitherium
Temporal occurrence
Upper Pliocene to Lower Pleistocene
3.6 to 0.781 million years
Locations
Systematics
Higher mammals (Eutheria)
Laurasiatheria
Unpaired ungulate (Perissodactyla)
Rhinocerotoidea
Rhinoceros (Rhinocerotidae)
Punjabitherium
Scientific name
Punjabitherium
Khan , 1971

Punjabitherium is an extinct member of the rhinoceros who lived around 2.5 million years ago at the transition from the Pliocene to the Pleistocene in South Asia . It is proven primarily on the basis of several skull finds. It was a large representative of the rhinoceros who was related to today's armored and Java rhinos. In contrast to these, however, it had two horns on its skull.

features

Punjabitherium was a large representative of the rhinos , which is largely only known from skull finds. This was extremely long with 75 to 76 cm in length and had a wedge-shaped shape when viewed from above , with the tips of the zygomatic arches up to 40 cm apart. In the side view, the forehead line showed a clear indentation, which was comparable to that of the genus Rhinoceros . The occiput had an obtuse angle and was so clearly drawn in, which also connects Punjabitherium with Rhinoceros . The nasal bone had a clearly rounded shape and was massive. There were roughened bone surfaces on both the nasal bone and the frontal bone, which showed the position of the two horns. Thus Punjabitherium had two horns in tandem, a nasal horn on the tip of the nose and a frontal horn on the forehead, which is a clear difference to the unicorned representatives of Rhinoceros . The overgrown bone cones (processus postglenoidalis and processusam posttympanicus) on the temporal bone below the auditory canal were also striking .

The lower jaw is only partially known, but its structure was basically similar to that of Rhinoceros . It reached a height of 9 cm, the symphysis was very strong and spatula-shaped and extended to the second premolar . Two incisors per jaw arch were formed in both the upper and lower jaw . Typically for rhinos, the upper incisors stood vertically in the jaw, while the lower incisors were directed forward, whereby the outer (I2) had a significantly enlarged and conical shape. The diastema to the posterior teeth was relatively extensive. The molars, consisting of premolars and molars , were clearly high crowned ( hypsodont ) and had conspicuously folded enamel . In the lower jaw, the rear dentition consisted of four premolars and three molars. The last tooth reached a length of up to 6.6 cm.

Fossil finds

Punjabitherium fossil finds come mainly from the Siwaliks in India and Pakistan . A partially complete skull, which lacks the front snout, comes from outcrops of the Yamuna River in what is now the Indian state of Himachal Pradesh in the northwest of the country and was discovered in the first half of the 19th century. From the same site, a back and front part of the skull are known, which were considered to belong to an individual, as well as a lower jaw. A very complete skull, which also provided the basis for the description of the genus, came to light near Chandigarh in the Indian Punjab . It can be assigned to the Pinjor Formation , a stratigraphic unit of the Upper Siwaliks that belonged to the transition from Pliocene to Pleistocene around 2.5 million years ago. Other, but isolated teeth are also known from Mirpur in Asad Kashmir in Pakistan and date to the Soan Formation with an early Pleistocene age.

Systematics

Punjabitherium is a genus of the family of rhinos is within which it part of the modern family of Rhinocerotinae is. The exact taxonomic assignment is not clear, but it is often placed in the sub- tribus Rhinocerotina together with the representatives of Rhinoceros living today , the armored rhinoceros ( Rhinoceros unicornis ) and the Java rhinoceros ( Rhinoceros sondaicus ), and the also extinct Gaindatherium . All members of this sub-tribus have the fused bone cones below the auditory canal and a clearly saddled course of the upper skull. Deviating from Gaindatherium and Rhinoceros , Punjabitherium has two well-developed horns, as well as higher-crowned molars and an elongated front snout area, so that it may represent a rather specialized side branch that arose around 10 million years ago. Gaindatherium, on the other hand, is significantly older, dating to the Middle Miocene, and has so far been viewed as a possible common ancestor of Punjabitherium and Rhinoceros . From the two-horned rhinos of Asia, such as the Sumatran rhinoceros ( Dicerorhinus sumatrensis ) living today, Punjabitherium differs in its missing, partially ossified nasal septum , and from those in Africa in its well-developed front teeth.

The first finds of Punjabitherium from the Yamuna River were assigned to the new species Rhinoceros platyrhinus by Hugh Falconer and Proby Thomas Cautley in 1847 , without describing the finds in more detail. This was only done posthumously by Falconer in 1868 . Further finds could be assigned in the course of time. Especially at the beginning of the 20th century, the fossils were assigned to the genus Coelodonta , whereby C. platyrhinus was now regarded as the ancestor of the woolly rhinoceros ( Coelodonta antiquitatis ) due to the presence of two horns and the high-crowned molars , but it was also moved because of the lower incisors a close position to the Sumatran rhinoceros and thus to the genus Dicerorhinus . Due to a newly discovered skull 1971 took place first description of Punjabitherium by Ehsanullah Khan . A study from 2016, on the other hand, classifies Punjabitherium as synonymous with Rhinoceros . The only recognized species of the genus Punjabitherium is P. platyrhinus . The generic name Punjabitherium refers to the find landscape of Punjab , while the Greek word θήριον ( thêrion ) means "animal". The species name platyrhinus , coined by Falconer and Cautley in 1847, is formed from the Greek words πλατις ( platys "broad") and ῥίς ( rhīs "nose"; genitive rhinos ).

Individual evidence

  1. ↑ a b c d Ehsanullah Khan: Punjabitherium, gen. Nov., An extinct rhinocerotid of the Siwaliks, Punjab, India. Proceedings of the Indian National Science Academy 37 (2) A, 1971, pp. 105-109
  2. ↑ a b Richard Lydekker: Indian Tertiary and Post-Tertiary Vertebrata: Siwalik Rhinocerotidae. Memoirs of the Geological Survey of India, Palaeontologia Indica 10 (2) 1. 1881, pp. 1-62
  3. ^ A b W. D. Matthew: Critical observations upon Siwalik mammals. Bulletin of the American Museum of Natural History, New York 56 (7), 1929, pp. 437-560
  4. ^ A b Abdul Majid Khan: Taxonomy and distribution of rhinoceroses from the Siwalik Hills of Pakistan. Department of Zoology, University of the Punjab, Lahore, 2009
  5. ↑ Esperanza Cerdeño: Cladistic analysis of the family Rhinocerotidae (Perissodactyla). American Museum Novitates 3143, 1995, pp. 1-25
  6. ↑ a b Colin P. Groves: The Rhinos - Tribal History and Kinship. In: Anonymus (Hrsg.): The rhinos: encounter with primeval colossi. Fürth 1997, ISBN 3-930831-06-6 , pp. 14-32
  7. ^ Hugh Falconer: On the species of fossil Rhinoceros found in the Sewalik Hills and On the fossil Rhinoceros of central Tibet and its relation to the recent upheaval of the Himalayahs. In: Palaeontological Memoirs and Notes of the late Hugh Falconer, compiled and edited by Charles Murchison Fauna Antiqua Sivalensis, London, 1868, pp. 157-172
  8. ^ Edwin H. Colbert: Siwalik mammals in the American Museum of Natural History. Transactions of the American Philosophical Society NS 26, 1935, pp. 1-401 (177-214)
  9. ↑ Luca Pandolfi and Leonardo Maiorino: Reassessment of the largest Pleistocene rhinocerotine Rhinoceros platyrhinus (Mammalia, Rhinocerotidae) from the Upper Siwaliks (Siwalik Hills, India). Journal of Vertebrate Paleontology, 2016 doi: 10.1080 / 02724634.2015.1071266