Ledi-Geraru

Ledi-Geraru is a paleoanthropological research area in Mille district, Afar Region, northeastern Ethiopia, along the Ledi and Geraru rivers (two left tributaries of the Awash, south of the Mille river). It stretches for about 50 km, located just to the northeast of the Hadar paleoanthropological area.

Ledi-Geraru
Paleoanthropological site
Ledi-Geraru
Coordinates: 11.25°N 40.70°E / 11.25; 40.70
Country	Ethiopia
Region	Afar

Early research was conducted in 1972–1974 The Ledi-Geraru Research Project was launched in 2002.^[1] The site is known for its early stone tools, dated about 2.6 million years old.^[2] A hominin mandible was found in 2013, known as LD 350-1 and dated 2.8 million years old, which may qualify as a very early specimen of the genus Homo.^[3]

LD 350-1

Main article: LD 350-1

LD 350-1 is a fossil hominin mandible fragment discovered in 2013 at the Ledi-Geraru site. It was found by Chalachew Seyoum, an Ethiopian graduate student in the Institute of Human Origins at Arizona State University. The fossil was stratigraphically dated to 2.80 to 2.75 million years old.^[4]

It has been described as combining "primitive traits seen in early Australopithecus with derived morphology observed in later Homo.^[5] The fossil is the left mandibular body, but does not include the ascending ramus. It has attached the three molars, both premolars, and the left canine, some of which have complete crowns.^[5]

See also

• Afar Triangle
• List of human evolution fossils

References

1. "Ledi-Geraru Research Project". ASU. Retrieved 5 August 2015.
2. Bruce Bower (June 3, 2019). "Hominids may have been cutting-edge tool makers 2.6 million years ago; Contested finds point to a sharp shift in toolmaking by early members of the Homo genus". ScienceNews.org. Retrieved June 5, 2019.
3. Jeanna Bryner. "Earliest Known Human Fossils Discovered". Livescience.com. Retrieved 5 August 2015.
4. Villmoare et al. (2015): "The Gurumaha Tuff is radiometrically dated to 2.842±0.007 Ma, a date that is consistent with the normal magnetic polarity of the Gurumaha section, presumably the Gauss Chron. An upper bounding age for LD 350-1 is provided by an adjacent, downfaulted younger block that contains the 2.665±0.016 Ma Lee Adoyta Tuff. [...] the age of LD 350-1 can be further constrained by stratigraphic scaling. [...] Based on the current chronostratigraphic framework for Ledi-Geraru, we consider the age of LD 350-1 to be 2.80-2.75 Ma". See also: DiMaggio, Erin N.; Campisano, Christopher J.; Rowan, John; Dupont-Nivet, Guillaume; Deino, Alan L.; Bibi, Faysal; Lewis, Margaret E.; Souron, Antoine; Garello, Dominique; Werdelin, Lars; Reed, Kaye E.; Arrowsmith, J Ramón (20 Mar 2015). "Late Pliocene fossiliferous sedimentary record and the environmental context of early Homo from Afar, Ethiopia". Science. 347 (6228): 1355–1359. Bibcode:2015Sci...347.1355D. doi:10.1126/science.aaa1415. PMID 25739409.
5. Villmoare, Brian; Kimbel, William H.; Seyoum, Chalachew; Campisano, Christopher J.; DiMaggio, Erin N.; Rowan, John; Braun, David R.; Arrowsmith, J. Ramón; Reed, Kaye E. (2015-03-20). "Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia". Science. 347 (6228): 1352–1355. Bibcode:2015Sci...347.1352V. doi:10.1126/science.aaa1343. ISSN 0036-8075. PMID 25739410.. See also: Erin N. DiMaggio EN; Campisano CJ; Rowan J; Dupont-Nivet G; Deino AL; et al. (2015). "Late Pliocene fossiliferous sedimentary record and the environmental context of early Homo from Afar, Ethiopia". Science. 347 (6228): 1355–1359. Bibcode:2015Sci...347.1355D. doi:10.1126/science.aaa1415. PMID 25739409..

• Dimaggio, E. N.; et al. (2015). "Tephrostratigraphy and depositional environment of young (<2.94 Ma) Hadar Formation deposits at Ledi-Geraru, Afar, Ethiopia". Journal of African Earth Sciences. 112: 234–250. doi:10.1016/j.jafrearsci.2015.09.018.