Eosimias

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Eosimias
Temporal occurrence
Middle Eocene
47.8 to 38 million years
Locations
Systematics
Euarchonta
Primates (Primates)
Dry- nosed primates (Haplorrhini)
Eosimiiformes
Eosimiidae
Eosimias
Scientific name
Eosimias
Beard , Qi , Dawson , Wang & Li , 1994
species
  • Eosimias sinensis Beard et al. 1994 (type)
  • Eosimias centennicus Beard et al. 1996
  • Eosimias dawsonae Beard and Wang 2004
  • Eosimias paukkaungensis (?) Takai et al. 2005

Eosimias ("Monkey of the Dawn") is an extinct genus of mammals and one of the most original representatives of the monkeys (Anthropoidea). This genus is so far only known from various finds of pines and a few leg bones, which come from the Middle Eocene of China and are ascribed to three different species. A possible fourth species comes from Myanmar , but the assignment of this species to Eosimias is only provisional.

features

It was a small representative of the monkeys. The lower jaw measures a length of about 2.6 centimeters; the body weight is estimated at 90 to 180 grams.

As with other representatives of the monkeys, the incisors were relatively small and aligned vertically. The canines were large, the molars were three-pointed and wide. The lower jaw was relatively deep. However, Eosimias differs from more advanced monkeys in a number of primitive features: the molars resembled those of the goblin tarsier , while the incisors are not spatulate like those of other monkeys, but represent an intermediate form between spatulate and tapering.

Systematics and types

Eosimias is the eponymous representative of the extinct family Eosimiidae . Other representatives of this family are Bahinia , Phenacopithecus and Philesomias . While most current studies consider the Eosimiidae to be the most primitive group of monkeys (Anthropoidea), critical voices note that the very fragmentary fossils would not be enough to reliably evaluate the family relationships of the group; For example, well-preserved skull finds are necessary in order to be able to confirm the classification within the monkeys.

So far, four species have been assigned to the genus Eosimias - in addition to the type species Eosimias sinensis (Beard et al. 1994), these are Eosimias centennicus (Beard et al. 1996), Eosimias dawsonae (Beard and Wang 2004) and Eosimias paukkaungensis (Takai et al. 2005). Christopher Beard and Jingwen Wang (2004) note, however, that the assignment of these species to Eosimias is fraught with uncertainty due to the very patchy fossil record - so it is possible that future studies will assign some of the species to other genera. The species Eosimias paukkaungensis appears to be particularly problematic - it is only known from a jaw discovered in Myanmar , whereby only the third molar of the dentition has been preserved - the assignment to the genus Eosimias is therefore only provisional.

Individual evidence

  1. ^ A b TS Kemp: The origin and evolution of mammals . Oxford University Press, Oxford [ua] 2005, ISBN 0-19-850760-7 , pp. 271 (English).
  2. ↑ a b c Masanaru Takai, Chit Sein, Takehisa Tsubamoto, Naoko Egi, Maung Maung, Nobuo Shigehara: A new eosimiid from the latest middle Eocene in Pondaung, central Myanmar . In: Anthropological Science . tape 113 , no. 1 , 2005, p. 17-25 (English).
  3. ↑ a b c Kenneth D. Rose: The beginning of the age of mammals . Johns Hopkins Univ. Press, Baltimore 2006, ISBN 0-8018-8472-1 , pp. 192-193 (English).
  4. ↑ a b Laurent Marivaux, Pierre-Olivier Antoine, Syed Rafiqul Hassan Baqri, Mouloud Benammi, Yaowalak Chaimanee, Jean-Yves Crochet, Dario De Franceschi, Nayyer Iqbal, Jean-Jacques Jaeger, Grégoire Métais, Ghazala Roohi, Jean-Loup Welcomme Anthropoid Primates from the Oligocene of Pakistan (Bugti Hills): Data on Early Anthropoid Evolution and Biogeography . In: Proceedings of the National Academy of Sciences . tape 102 , no. 24 , May 14, 2005, pp. 8436-8441 , doi : 10.1073 / pnas.0503469102 (English, pnas.org ).
  5. ↑ Eosimiidae. In: The Paleobiology Database. Retrieved May 18, 2012 .
  6. ↑ K. Christopher Beard, Jingwen Wang: The eosimiid primates (Anthropoidea) of the Heti Formation, Yuanqu Basin, Shanxi and Henan Provinces, People's Republic of China . In: Journal of Human Evolution . tape 46 , no. 4 , March 2004, p. 401-432 , here pp. 403-405 , doi : 10.1016 / j.jhevol.2004.01.002 (English, ukpmc.ac.uk ).