LD 350-1
 LD-350-1 mandible | |
| Common name | LD 350-1 |
|---|---|
| Species | Homo, species uncertain |
| Age | 2.775 million years |
| Place discovered | Afar, Ethiopia |
| Date discovered | 29 January 2013 |
| Discovered by | Chalachew Seyoum |
LD 350-1 is the earliest known specimen of the genus Homo, dating to 2.75–2.8 million years ago (mya), found in the Ledi-Geraru site in the Afar Region of Ethiopia. The specimen was discovered in silts 10 m (33 ft) above the Gurumaha Tuff section of the site[1][2] by Ethiopian palaeoanthropologist Chalachew Seyoum on 29 January 2013. It is currently unassigned to a species, and it is unclear if it represents the ancestor to H. habilis and H. rudolfensis which evolved around 2.4 mya.[1]
Description
LD 350-1 is an adult left jawbone including the
Classification
The origin of Homo 2.8–2.5 mya is accompanied by climatic changes, but because other Homo specimens are not known from this time period, it is unclear if this was indeed the causal factor.[1] Because of the strong dental divergence exhibited in LD 350-1, it may be that the initial split was caused by a change in diet.[3] The KNM-ER 5431 specimen (comprising left and right premolars and the first two molars) from Koobi Fora, Kenya, dating to 3–2.7 mya could represent the same species as LD 350-1. The discovery of such an early Homo specimen discredits some past hypotheses on the timing of the Australopithecus/Homo transition, including deriving 2.6 mya from A. garhi. It is unclear if A. afarensis, which is known from the same region until 3 mya, was an ancestor to LD 350-1.[1]
Culture
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In 2019, the earliest Oldowan stone tools were discovered in Ledi-Geraru dating to 2.6 mya and may have been manufactured by the same species as LD 350-1. The invention of the sharp-edged Oldowan may be tied to unique biological changes in Homo. It is unclear if the Oldowan developed independently or from earlier, simpler australopithecine stone traditions (the only one identified is the Lomekwi industry). In either case, the transition to sharper tools would have allowed different feeding strategies and the ability to process a wider range of foods than australopithecine technology permitted, which would have been advantageous in the changing climate of the time.[4]
LD 350-1 lived in a much drier and more open environment than A. afarensis typically inhabited.