Archicebus

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Archicebus
Temporal occurrence
Eocene ( Ypresian )
approx. 55.8 to 54.8 million years
Locations
Systematics
Euarchonta
Primates (Primates)
Dry- nosed primates (Haplorrhini)
Tarsiiformes
Archicebidae
Archicebus
Scientific name of the  family
Archicebidae
Ni , Gebo , Dagosto , Meng , Tafforeau , Flynn & Beard , 2013
Scientific name of the  genus
Archicebus
Ni, Gebo, Dagosto, Meng, Tafforeau, Flynn & Beard, 2013
Art
  • Archicebus achilles  Ni et al., 2013

Archicebus is a genus of the dry- nosed primates (Haplorhini), whose representativeslivedin East Asia during the early Eocene (54.8-55.8  mya ). Archicebus achilles , the only species of the genus, was a slender, 20-30 g heavy and a total of about 23 cm long animal that was native to eastern Asia. Archicebus lived in the tops of trees, was probably diurnal and ate mainly insects. The fossil remains of archicebus come from the Chinese Yangxi lineup . The genus was in 2013 by Ni Xijun , Daniel Gebo , Marian Dagosto , Meng Jin , Paul Tafforeau , John J. Flynn and Christopher Beard erected . According to phylogenetic studies, it is a very early representative of the Tarsiiformes , i.e. the branch of the primates that is stillrepresentedtoday by the Koboldmakis (Tarsiidae). Archicebus is the oldest species of animal that can be clearlyassigned tothe primates .

features

Archicebus achilles was a very small primate. The skull of the holotype is 25 mm long, its rump was estimated to be 71 mm long during its lifetime. The tail of the fossil is 129 mm long. On the basis of a model developed for Teilhardina asiatica , the live weight of the species is estimated at 24.52–38.77 g. A. achilles points with I 2/2 - C 1/1 - P 4/4 - M 2 /? probably the same tooth formula as other primates such as Teilhardina or Tetonius . The teeth of the species are relatively long and pointed, especially the premolars have sharp, well-developed shear edges. A. achilles' legs are significantly longer than the arms. The construction of the feet, especially the calcaneus , is more like monkeys than goblin tarsiers . For tarsiiforms , the tarsus is very short, the metatarsus extremely, and the toes relatively long. Overall, at 33.5 mm, the foot reaches around 37% of the leg length. Archicebus shows characteristics typical of both tarsiers and monkeys (Anthropoidea).

Ecology and diffusion

Archicebus lived in Eastern Asia when it was still separated from Africa , India , Europe and the Alpidian Islands by the Tethys . Its habitat was warm and humid, as pollen analyzes suggest. Its sharp, high teeth identify Arcicebus as an insect eater , while the long hind legs, the strongly developed fingers and the very long tail are characteristic of a climbing way of life, as it still occurs in many small primates today. The short arms suggest, however, that the genus was not specialized in moving around in the branches. Archicebus' eyes are stereoscopic and relatively large, but significantly smaller than the more recent goblin lemurs. So the animals orientated themselves strongly on the basis of the visual sense, but were probably diurnal.

Fossil material and stratigraphy

The known fossil material from Archicebus comes from a single individual and comprises a largely complete skeleton ( inventory number IVPP V18618). Most of the bones are preserved, only the front spine, parts of the lower jaw and the hands are missing. The skeleton was uncovered from the lower Yangxi Formation near Jingzhou , China . The formation gathers numerous genera typical for the fauna age of the Bumbanium (55.8–54.8  mya ), but only a few mammals. The Archicebus layer contains many microfossils that are characteristic of both the late Paleocene and the early Eocene . The genus is therefore dated to the earliest Ypresian , just above the Paleocene-Eocene boundary.

Systematics and taxonomy

  Primates  

 Wet-nose primates (Strepsirrhini)


  Dry-nosed primates 

 Monkey (anthropoidea)


  Tarsiiformes  

 Archicebus


   

 remaining tarsiiformes





Systematic position of Archicebus within the primates according to Ni et al. (2013). The cladogram is based on the combined evaluation of 1186 morphological and 658 molecular properties, the underlying analysis comprised 119 fossil and 38 recent species.

The genus archicebus was 2,013 of Ni Xijun , Daniel Gebo , Marian Dagosto , Meng Jin , Paul Tafforeau , John J. Flynn and Christopher Beard on the basis of the skeleton from the Yangxi lineup set up and assigned to a family, the Archicebidae. The generic name is made up of the Greek "arche / ἀρχή" for "origin" and the Latin "cebus" for "tail monkey". Based on the ape-like calcaneus of the holotype , the authors gave the species the epithet achilles , which refers to the hero Achilles from Greek mythology . Achilles is only vulnerable at his heel and eventually dies after being injured.

A statistical analysis carried out by the first descriptions of 1186 morphological and 658 molecular characteristics classified Archicebus among 38 recent and 119 fossil taxa as the most original representatives of the Tarsiiformes . Since the genus shows a mosaic of properties that are typical either for monkeys or for tarsiiformes, it is probably very close to the last common ancestor of monkeys and tarsier both in time and in appearance.

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literature

  • Xijun Ni, Daniel L. Gebo, Marian Dagosto, Jin Meng, Paul Tafforeau, John J. Flynn, K. Christopher Beard: The oldest known primate skeleton and early haplorhine evolution . In: Nature . tape 498 , no. 7452 , 2013, p. 60–64 , doi : 10.1038 / nature12200 .

Web links

Individual evidence

  1. ↑ Ni et al. 2013, supplement p. 8.
  2. ↑ Ni et al. 2013, supplement p. 23.
  3. ↑ Ni et al. 2013, pp. 60–63.
  4. ↑ Ni et al. 2013, supplement p. 3.
  5. ↑ Ni et al. 2013, pp. 63–64.
  6. ↑ Ni et al. 2013, Supplement pp. 2-4.
  7. ↑ a b Ni et al. 2013, p. 63.
  8. ↑ Ni et al. 2013, pp. 60–63.
  9. ↑ Ni et al. 2013, p. 60.
  10. ^ Perkins 2013. Retrieved June 8, 2013.