Ledi-Geraru, Ethiopia: 13 teeth reveal coexistence of a new Australopithecus and the oldest homo. A branched, non -linear evolution.
An international group of paleoanthropologists has created a discovery of great value on the Ledi-Geraru website, in the Afar region, in Ethiopia: 13 fossil teeth-dating back to about 2.6–2.8 million years ago-which indicate the simultaneous presence in a single place of An unknown Australopithecus and the oldest specimens of the homo genre. According to Brian Villmoare, the first author of the study published on Natureit is the confirmation that Homo and Australopithecus coexisted in the same period and in the same African territory.
Because this discovery is important
The discovery confirms once again that there was no A linear evolution of our Trisanti, but an intricately branched tree scenario. Also Kaye Reed, Paleoecologist of the Arizona State University and the Ledi-Geraru Research Project from 2002, stressed that “this discovery shows that the evolutionary perception of monkey-neanderthal-modern man is misleading: human evolution forms a bushy shrub, with species that cohabit, extinguish and diverge”.
The 13 teeth include 10 attributed to two specimens of Australopithecus, sufficiently other than not to match with Australopithecus Aparensis (the famous “Lucy”), currently dated up to about 2.95 million years ago. The other 3 teeth have characteristics attributable to the oldest Homo known, therefore most likely a homo habilis. For now, however, the researchers have not given a name to the new species of Australopithecus: more complete fossils will be needed for an official description.
The importance of the place of the discovery
The Ledi-Geraru website is located in a geologically active region, where frequent volcanic eruptions have deposited ashes rich in feldspati (rich in silice minerals and other elements), useful for dating the stratigraphic levels with methods based on the decay of potassium-argon: the teeth are set between two eruptive events dated thanks to these techniques.
Already in 2013, the same site returned the LD 350-1 mandibola-the oldest find attributed to the Homo genre, dating back to around 2.75–2.8 million years ago. In addition, dating back to about 2.6 million years ago, the first were found Olduvaian Lithic industries. The environment of the time was very different from the current desert morphology: they were grassy plains crossed by rivers that resulted in shallow lakes, surrounded by dense vegetation and rich in grassy and aquatic fauna.
Someone doubts that it is a new species
Not all scholars, however, have accepted the interpretation that the teeth belong to a new species. Some experts warn against outlining the Australopithecus discovered as from scratch on the basis of only teeth, highlighting possible possible intraspish or evolutionary variations.
In any case, Villmoare and Reed observe that, for now, it is certain that Homo and Australopithecus lived in contact and the recent discoveries are a further test, but it remains uncertain if they confrontation for the resources, they hybridized or if they fought with each other. To resolve these questions it will be crucial to discover new fossils, in particular bone, in order to analyze anatomy, diet (through dental enamel) and behaviors.