Nsungwepithecus
| Nsungwepithecus | ||||||||
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| Oligocene ( Chattian ) | ||||||||
| 25.2 million years | ||||||||
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| Scientific name | ||||||||
| Nsungwepithecus | ||||||||
| Stevens et al., 2013 | ||||||||
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Nsungwepithecus is an extinct genus of primates that was foundin East Africa during the Oligocene . The only fossil discoveredso far near the city of Mbeya in Tanzania that is ascribed to this genus was dated around 25 million years ago. The only described species of the genus is Nsungwepithecus gunnelli .
Naming
Nsungwepithecus is an artificial word . The name of the genus refers to the Nsungwe formation appointed stratum of the Rukwa basin in the southwestern Tanzania, from the holotype was recovered from genus and species. The second half of the generic name is derived from the Greek word πίθηκος ( pronounced píthēkos in ancient Greek : "monkey"). The epithet gunnelli honors the American paleontologist Gregg F. Gunnell (1954–2017) "for his numerous contributions to the paleontology of primates."
Initial description
The holotype of Nsungwepithecus is the fragment of a left lower jaw with preserved molar M3 with the archive number RRBP 11178 (RRBP = Rukwa Rift Basin Project) from the Nsungwe 2B site. The fossil was recovered during the 2011/12 excavation campaign. It lay between two volcanic tuff layers , for which an age of 25.237 and 25.214 million years was determined with the help of uranium-lead dating .
Due to the nature of the tooth only preserved the fossil was superfamily of tailed Old World monkeys, that is the form circle of Cercopithecidae attributed. According to the first description published in May 2013 , the tooth has a unique combination of nine characteristics compared to other fossil finds that belong to the superfamily, on the basis of which a new genus had to be established for it. These features include, in particular, the considerable size of the tooth, the undivided mesial tooth root , low and rounded tooth cusps and a clearly recognizable, centrally arranged minor cusp called hypoconulid at the rear end of the tooth.
Importance of the find
Using the molecular clock Geneticists have calculated that some 25 to 30 million years in the lineage of the Old World monkeys to today's human-like leading line of development from the tailed Old World monkeys (which includes u. A. Vervet monkeys , baboons and macaques ) has disconnected. Since the exact “speed” of the molecular clock, that is, the frequency of mutations in past epochs, is unknown, the calibration of the molecular clock depends on reliably dated fossil finds. However, until the Nsungwepithecus fossil was discovered, there were only three scientifically described primate genera ( Kamoyapithecus , Saadanius and Propliopithecus ) that are older than 20 million years. Only the joint find of Nsungwepithecus - a tailed Old World monkey - and the fossil of Rukwapithecus - a genus of the human species found in the same layer - provided paleontological evidence for the separation of the two lines of development in the Upper Oligocene , should the interpretations of both finds be valid .
Tectonic processes ( uplifts ) in the area of the East African rift system were described as contributing to the separation of both lines of development in this epoch .
Web links
- Nsungwepithecus on fossilworks.org
- Video: animation of the holotype of Nsungwepithecus
- Rukwa Rift Basin Project website
Individual evidence
- ↑ a b Nancy J. Stevens et al .: Palaeontological evidence for an Oligocene divergence between Old World monkeys and apes. In: Nature . Volume 497, 2013, pp. 611-614, doi: 10.1038 / nature12161 .
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^ Obituary in The Cedar Springs Post dated November 2, 2017.
Gregg Gunnell, Fossil Hunter, Dies at 63. Obituary dated September 25, 2013 on the Duke University server - ^ Jan E. Janečka et al .: Molecular and Genomic Data Identify the Closest Living Relative of Primates. In: Science . Volume 318, No. 5851, 2007, pp. 792-794, doi: 10.1126 / science.1147555 .
- ^ Fossils indicate common ancestors for two primate groups. On: nature.com from May 15, 2013.
- ↑ Ancestors of modern primates: Finds fill gaps in the family tree. On: spiegel.de from May 17, 2013.
- ↑ Fossils May Pinpoint Critical Split Between Apes and Monkeys. On: sciencemag.org from May 15, 2013.
- ↑ Eric M. Roberts et al .: Initiation of the western branch of the East African Rift coeval with the eastern branch. In: Nature Geoscience. Volume 5, 2012, pp. 289-294, doi: 10.1038 / ngeo1432 .