Afradapis
| Afradapis | ||||||||||||
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| Eocene | ||||||||||||
| 37 million years | ||||||||||||
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| Scientific name | ||||||||||||
| Afradapis | ||||||||||||
| Seiffert , Perry , Simons & Boyer , 2009 | ||||||||||||
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Afradapis is a genus of primates from the extinct group of Adapiformes . The approximately 37 million year old fossil remains from the Eocene were discovered in the Fayyum in Egypt and scientifically described by an international group of researchers in 2009. The only known species is Afradapis longicristatus .
The genus Afradapis was interpreted as a close relative of the genus Darwinius , its teeth as a convergence to the reduction of the teeth in the line of development leading to the great apes. According to the first description , the genus as an extinct sister group - probably already in the Eocene - is close to today's lemurs and loric species . According to its discoverer, remains of nearly 40 individuals had been discovered by the end of 2009.
Naming
Afradapis is an artificial word . The name of the genus is derived from "afra", the Latin word for Africa , as well as from the species name Adapis introduced by Frédéric Cuvier in 1821 for a genus of primates from the Eocene in Europe. The epithet of the only scientifically described species so far, Afradapis longicristatus , is also derived from Latin, namely from "longi-" = long and "cristatus" = carrying a comb ; In this genus, the chewing surfaces of the teeth are designed like a comb . Afradapis longicristatus therefore means "African adapis with oblong, comb-like chewing surfaces".
Initial description
As holotype of the species and also the type species Afradapis longicristatus , the first description (83690 VSN CGM) with four obtained molars (4, a fragment of a juvenile left mandibular premolar to 3. Molar ) and joint approach from. In addition, other fossils are listed (paratypes), including two lower jaw fragments with two or three preserved molars , ten molars, eight incisors and two canines .
These remains came from several individuals who lived in the late Eocene ( Priabonian ) and were among the more common mammals in the area of the Egyptian excavation site - derived from the numerous finds. With an estimated weight of 3.2 kg, they were the largest primates discovered to date in the area of the Birket Quarun Locality (BQ-2).
The lack of the 2nd premolars, the narrow, beveled 3rd premolars of the upper and lower jaw and various features of the tooth cusps are highlighted as special features. The surface of the molars of the upper and lower jaw is similar to that of recent primates living on leaf food such as howler monkeys , sifakas and indri . However, the authors of the first description argue that the comb-like elevations of the chewing surfaces is no evidence of a closer relationship to these recent species, since this characteristic has developed several times independently of one another as an adaptation to certain foods in the sense of homoiology . Nevertheless, they admit that Afradapis share a particularly large number of tooth and lower jaw features with the real apes (Anthropoidea). However, they explain that these features are still missing in the indisputably original fossils of the Anthropoidea - for example Biretia and Proteopithecus - and therefore emerged relatively late in the tribal history of this group.
Find history and systematics
The first teeth and mandible fragments of Afradapis longicristatus were discovered in 2000 about 60 km southwest of Cairo in the Fayyum. In the following years, more teeth were exposed, so that by the beginning of 2009 almost all of the lower teeth and parts of the upper jaw could be reconstructed. The planned first description of the genus Afradapis was postponed in spring 2009 after the newly discovered species Darwinius had been assigned to the ancestral line of the dry-nosed monkeys - from which Homo sapiens arose. The fossils from the Fayyum were then compared on the basis of 360 anatomical features with 117 partly recent and partly fossil primate species in order to ensure the classification of the finds in the primate family tree . Even after completing these morphological comparisons (including the holotype of Darwinia ), the research group stuck to their assessment that the molars show typical features of early wet-nosed monkeys : on the one hand, they are relatively elongated, on the other hand, they lack the front hump. Jørn Harald Hurum , who was instrumental in the first description of Darwinia , insisted that the group of Adapiformes should be assigned to the dry-nosed monkeys.
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Web links
- sueddeutsche.de of October 22, 2009: “A distant relative. Researchers delete Ida from the human family tree. "
Individual evidence
- ↑ Erik R. Seiffert, Jonathan MG Perry, Elwyn L. Simons and Doug M. Boyer: Convergent evolution of anthropoid-like adaptations in Eocene adapiform primates. In: Nature . Volume 461, 2009, pp. 1118-1121, doi: 10.1038 / nature08429
- ↑ Rex Dalton: Fossil primate challenges Ida's place. In: Nature. Volume 461, 2009, p. 1040, doi: 10.1038 / 4611040a
- ↑ " Darwinius as a skeleton is much more complete than Afradapis , and Darwinius shows additional haplorhine characteristics not preserved here." Quoted from: Rex Dalton: Fossil primate challenges Ida's place. In: Nature. Volume 461, 2009, p. 1040, doi: 10.1038 / 4611040a