|Oligocene ( Chattian )|
|25.2 million years|
|Stevens et al., 2013|
Rukwapithecus 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 Rukwapithecus fleaglei ; It was very early relative of the ancestor of all apes interpreted.
Rukwapithecus is an artificial word . The name of the genus refers to the site where the holotype of genus and species in the East African grave system associated Rukwa Basin in southwestern Tanzania. The second half of the generic name is derived from the Greek word πίθηκος ( pronounced píthēkos in ancient Greek : "monkey"). The epithet fleaglei honors the American paleontologist John G. Fleagle "for his numerous studies on the morphology , behavior and evolution of primates."
Rukwapithecus holotype is the fragment of a right lower jaw with four preserved teeth ( premolar P4 to molar M3) with archive number RRBP 12444A (RRBP = Rukwa Rift Basin Project) from the location Nsungwe 2B. 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 teeth, the fossil was ascribed to the superfamily of the human species , that is, the gibbons and the great apes. According to the first description published in May 2013 , the teeth show 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 the lower jaw. During their lifetime, the body weight of the animals could have been around 12 kilograms, comparable to a Siamang .
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 is dependent on reliably dated fossil finds. However, until the discovery of the Rukwapithecus fossil, there were only three scientifically described primate genera ( Kamoyapithecus , Saadanius and Propliopithecus ) that are older than 20 million years. Only the joint discovery of Nsungwepithecus - a tailed Old World monkey - and the fossil of Rukwapithecus found in the same layer has provided paleontological evidence for the separation of the two lines of development in the Upper Oligocene .
- Rukwapithecus on fossilworks.org
- Video: animation of the holotype of Rukwapithecus
- Fossils May Pinpoint Critical Split Between Apes and Monkeys. On: sciencemag.org from May 15, 2013.
- Rukwa Rift Basin Project website
- 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 .
- Oldest Fossils Reveal When Apes & Monkeys First Diverged. On: livescience.com on May 15, 2013.
- 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.
- 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 .