Forstercooperia

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Forstercooperia
Temporal occurrence
Lutetium (Middle Eocene ) to Bartonian (Upper Eocene)
47.8 to 33.9 million years
Locations
Systematics
Mammals (mammalia)
Higher mammals (Eutheria)
Laurasiatheria
Unpaired ungulate (Perissodactyla)
Indricotheriidae
Forstercooperia
Scientific name
Forstercooperia
Wood , 1939

Forstercooperia is an extinct genus of the family of Indricotheriidae and thus belongs to the close relationship of today's rhinos . It is the smallest and most pristine representative of this fossil mammal group, which with Paraceratherium was also the largest known land mammal in geological history, and livedin Central and East Asiain the Middle and Upper Eocene 48 to 37 million years ago. In the second half of the 20th century, Forstercooperia was regarded as the only form of Indricotheria that also occurred in North America, but this has now been refuted. The first valid description of the genus was made in 1939. Several species are recognized.

features

They are medium-sized representatives of the mammals , which reached about the size of today's ponies . The genus is largely known from individual skull and tooth finds. The skull itself was at least 40 cm long and had a slightly extended occiput . The primal position of the genus is indicated by a small crest . The nasal bone had a obtuse triangular shape when viewed from above and was slightly arched when viewed from the side, but was overall weak. The forehead line was slightly arched. The orbit was located relatively far back in the skull and was above the third molar . The front skull also had a small, linear elevation that began near the canine and extended to the area above the eye compartment. This elevation is seen as the muscle attachment point for a highly mobile upper lip, which may also have formed a short, tapir-like trunk.

The lower jaw was about 36 cm long and built low. The bite was the complete original number of teeth, so the teeth formula was: . The anterior dental apparatus did not form a closed row. The incisors were conical in shape and resembled the canine . In addition, they were small in size and not very specialized. The canine, on the other hand, was much larger and up to 1.8 cm long. There was a short diastema at each of the rear teeth . The premolars were relatively small and, due to the presence of only one transverse enamel band, did not show any molarization, that is, they differed significantly from the molars . These were much larger in size, with the second molar being the largest, and also had two enamel bands, but they were only slightly twisted. The primitive structure of the dentition with the non-molarized premolar teeth and the unspecialized incisors reflect the basal position of Forstercooperia within the Indricotheria. The rear teeth had rather low tooth crowns ( brachyodont ).

References

Remains of Forstercooperia have so far only come down to us from Asia . A partially preserved skull found in 1923 comes from the Irdin-Manha Formation near Iren Dabasu in the eastern part of the Erlian Basin in Inner Mongolia ( China ) and has a late-Ocene age. It represents the holotype of the genus. In the same formation, but several kilometers from the first find, another skull with a lower jaw of an adult animal and a lower jaw of a younger animal together with isolated teeth was discovered seven years later. A 45 cm long skull from the Ulan-Shireh formation is available from the western section of the Erlian Basin . Other finds come from eastern Kazakhstan , where they were also found in Middle Eocene deposits near the mouth of the Shinchali .

Systematics

Internal systematics of the family of the Indricotheriidae according to Wang et al. 2016
 Indricotheriidae 


 Pappaceras


   

 Forstercooperia



   

 Juxia


   

 Urtinotherium


   

 Paraceratherium





Template: Klade / Maintenance / Style

Forstercooperia belongs to the extinct family of the Indricotheriidae , which represent medium-sized to very large animals and are closely related to today's rhinos . In contrast to rhinos, the Indricotheria did not develop a horn. Further differences can be found in the front dentition, which in the Indricotheria consisted of short, conically shaped incisors both above and below , which in more modern forms developed into a pair of dagger-like teeth. In contrast to this, the earliest rhinos only had dagger-like incisors in the lower jaw, while in the upper they had a chisel-like shape. Forstercooperia represents the most primitive member of the family due to its age, small size and simple tooth morphology. Due to the small size and the unspecialized front teeth, some paleontologists see the genus together with the phylogenetic successor Juxia occasionally in a close relationship to Eggysodon (family of Eggysodontidae , partly also subfamily of Alloceropinae within Hyracodontidae ). As a rule, Forstercooperia is now placed together with Pappaceras to the subfamily of Forstercooperiinae within the Indricotherien.

Several species of the genus Forstercooperia have been described, three of which are valid today:

  • Forstercooperia mazhuangensis ( Wang , 1976)
  • Forstercooperia totadentata ( Wood , 1938)
  • Forstercooperia ulanshirehensis Wang , Bai , Meng & Wang , 2018

For a long time, F. confluens and F. minuta were other species . F. confluens was originally described as Pappaceras by Horace Elmer Wood in 1963 , but subsequent analyzes assigned both the species and the genus to Forstercooperia . A study from 2016 recognizes the genus Pappaceras , including the nominate form established by Wood , the species F. minuta established by Spencer George Lucas and colleagues in 1981, and a new form, Pappaceras meiomenus , and interprets them as a sideline within the Indricotheria . With F. shiwopuensis , Chow Minchen and colleagues established a further species in 1974, which is considered synonymous with F. totadentata . The species F. jigniensis , which was newly named in 1972 and whose description is based on fragmented teeth from Pakistan , is also heavily questioned . In contrast, F. crudus , informally used in 1977 for some remains of teeth from the Zaisan Basin in Kazakhstan , is considered to be the noun nudum . Juxia , named by Chow Mincheng in 1964, was equated only three years later by Leonard B. Radinsky with Forstercooperia , which received little support. The genus is therefore again considered to be independent. In 1976, Wang Jinmeng established the genus Irmequincisoria with the species I. mazhuangensis and I. micracis based on individual remains of the upper jaw and teeth from the Wucheng Basin in the Chinese province of Henan . Later authors saw the genus Irmequincisoria as identical to Juxia . However, the species I. mazhuangensis was moved to Forstercooperia in 2007 .

Forstercooperia partly had the status of the only known representative of the Indricotherien in North America. This goes back to Leonard Radinsky , who in 1967 renamed the fossils from the Uinta Basin in Utah to F. grandis , which had already been described as Hyrachyus grande in 1919 . Other remains are from Wyoming , in 1981 Spencer George Lucas and colleagues assigned a lower jaw bone from New Mexico of the species F. minuta . The discovery of further bone finds in Utah in 1987 and subsequent anatomical studies of the findings of F. grandis led to the dissolution of the species and the establishment of the new genus Uintaceras . Depending on the point of view, this belongs either to the basis of the development of the rhinos or to the immediate vicinity of the Indricotheria. The lower jaw of F. minuta was excluded from the Indricotheria after the shift to the genus Pappaceras .

The Erstbenennung of Forstercooperia was made in 1938 by Horace Elmer Wood under the name Cooperia , you were findings of a partial skull with front muzzle from Mongolia basis (copy number: AMNH -20,116), which in 1923 during an expedition of the American Museum of Natural History had been found . Since the original genus name Cooperia was already used in a genus of roundworms and is thus preoccupied, Wood renamed it Forstercooperia in 1939 . This publication represents the first valid description of the genus. Both names refer to the British paleontologist Clive Forster Cooper , who in 1911 described Paraceratherium, the largest and most evolutionarily young representative of the Indricotheriidae.

literature

  • Haibing Wang, Bin Bai, Jin Meng and Yuanqing Wang: Earliest known unequivocal rhinocerotoid sheds new light on the origin of Giant Rhinos and phylogeny of early rhinocerotoids. Scientific Reports 6, 2016, p. 39607 doi: 10.1038 / srep39607
  • Horace Elmer Wood: Cooperia totadentata, a remarkable rhinoceros from the eocene of Mongolia. American Museum Novitates 1012, 1938, pp. 1-22

Individual evidence

  1. ↑ a b Demberelyin Dashzeveg: A new Hyracodontid (Perissodactyla, Rhinocerotoidea) from the Ergilin Dzo formation (Oligocene Quarry 1) in Dzamyn Ude, Eastern Gobi Desert, Mongolia. American Museum Novitates 3178, 1996, pp. 1-12
  2. ↑ a b c d e Horace Elmer Wood: Cooperia totadentata, a remarkable rhinoceros from the eocene of Mongolia. American Museum Novitates 1012, 1938, pp. 1-22
  3. ^ A b c d Luke T. Holbrook and Spencer George Lucas: A new genus of rhinocerotoid from the Eocene of Utah and the status of North American "Forstercooperia". Journal of Vertebrate Paleontology 17 (2), 1997, pp. 384-396
  4. ↑ a b c Horace Elmer Wood: A primitive rhinoceros from the late eocene of Mongolia. American Museum Novitates 2146, 1963, pp. 1-12
  5. ↑ a b c d Hai-Bing Wang, Bin Bai, Jin Meng and Yuan-Qing Wang: A New Species of Forstercooperia (Perissodactyla: Paraceratheriidae) from Northern China with a Systematic Revision of Forstercooperiines. American Museum Novitates 3897, 2018, pp. 1–41
  6. ↑ Болат У. Байшашов: Биоразнооърие непарнокопытных (Perissodactyla) палегена восточного Казахстана. In: AM Meldebekov, M. Kh. Baizhanov, AF Kovshar, AB Bekenov, PA Tleuberdina, VL Kazenas, IN Magda and ZZ Sajakova (eds.): Zoological researches of the 20 years of independence of Republic of Kazakhstan. Materials of the International scientific conference devoted to the 20 years of independence of Republic of Kazakhstan. On September, 22-23, 2011. Almaty, 2011, pp. 306-308
  7. ↑ a b c d e Haibing Wang, Bin Bai, Jin Meng and Yuanqing Wang: Earliest known unequivocal rhinocerotoid sheds new light on the origin of Giant Rhinos and phylogeny of early rhinocerotoids. Scientific Reports 6, 2016, p. 39607 doi: 10.1038 / srep39607
  8. ^ Leonard B. Radinsky: The families of the Rhinocerotoidea (Mammalia, Perissodactyla). Journal of Mammalogy 47 (4), 1966, pp. 631-639
  9. ^ A b c Leonard B. Radinsky: A review of the Rhinocerotoid Family Hyracodontidae (Perissodactyla). Bulletin of the American Museum of Natural History 136 (1), 1967, pp. 1-47
  10. ↑ Donald R. Prothero, Earl Manning and C. Bruce Hanson: The phylogeny of the rhinocerotoidea (Mammalia, Perissodactyla). Zoological Journal of the Linnean Society 87, 1986, pp. 341-366
  11. ^ A b c Zhan-Xiang Qiu and Ban-Yue Wang: Paracerathere fossils of China. Palaeontologia Sinica 193 (New Series C, 29), 2007, pp. 1–396 (pp. 247–386 in English)
  12. ↑ a b c d e Spencer G. Lucas, Robert M. Schoch and Earl Manning: The Systematics of Forstercooperia, a Middle to Late Eocene Hyracodontid (Perissodactyla: Rhinocerotoidea) from Asia and Western North America. Journal of Paleontology 55 (4), 1981, pp. 826-841
  13. ^ A b c Spencer George Lucas and Jay C. Sobus: The systematics of Indricotheres. In: Donald R. Prothero and R. Schoch (Eds.): The evolution of Perissodactyls. New York: Oxford Univ. Press., 1989, pp. 358-378
  14. ↑ Chow Minchen, Chang Yu-Ping and Ting Su-Yin: Some Early Tertiary Perissodactyla from Lunan Basin, E. Yunnan. Vertebrata Palasiatica 12 (4), 1974, pp. 262-274
  15. ↑ JGM Thewissen, PD Gingerich and DE Russell: Artiodactyla and Perissodactyla (Mammalia) from the early middle Eocene Kuldana formation of Kohat (Pakistan). Contributions from the Museum of Paleontology 27 (10), 1987, pp. 247-274
  16. ↑ Chow Minchen and Chiu Chan-Siang: An eocene giant rhinoceros. Vertebrata Palasiatica 8 (3), 1964, pp. 264-268
  17. ^ Donald R. Prothero: Rhino giants: The palaeobiology of Indricotheres. Indiana University Press, 2013, pp. 1-141 ISBN 978-0-253-00819-0
  18. ↑ Wang Jingwen: A New Genus of Forstercooperiinae from the Late Eocene of Tongbo, Henan. Vertebrata Palasiatica 14 (2), 1976, pp. 104-111
  19. ↑ Donald R. Prothero: The evolution of North American rhinoceroses. Cambridge University Press, 2005, pp. 1-219

Web links

Commons : Forstercooperia  - collection of images, videos and audio files