The genus Homo is older than thought…

Another close-up view of the Homo mandible, LD350-1, shown just steps from where Arizona State University graduate student Chalachew Seyoum from Ethiopia spotted it. The scientists involved in the discovery aren’t sure if the fossil belongs to a new species or to a known, extinct human species, such as Homo habilis. They plan to learn more about the fossil before making that decision and giving it a name. (Photo credit: Kaye Reed)

Scientists sieve through sand at the Ledi-Geraru site at the Afar Regional State in Ethiopia, where they discovered the Homo mandible, known as LD 350-1. (Photo credit: Brian Villmoare)

Chris Campisano, of Arizona State University, samples a tuff in the Ledi-Geraru project area in Ethiopia with support from Sabudo Boraru. (Photo credit: J Ramón Arrowsmith)

The mandible of a hippo was also discovered at the Ledi-Geraru site. The mandible is still in the ground there, said study researcher Brian Villmoare of the University of Nevada Las Vegas. (Photo credit: Brian Villmoare)

Another view of a camel caravan as the animals move across the so-called Lee Adoyta region in the Ledi-Geraru research site near where researchers discovered the early Homo mandible. The hills behind the camels reveal sediments that are younger than 2.67 million year old, providing a minimum age for the partial mandible dubbed LD 350-1, say the scientists. (Photo credit: Erin DiMaggio, Penn State)

Geologists work in the field at the Ledi-Geraru site in Ethiopia, where they discovered a partial mandible, with five of its teeth intact, belonging to an individual in the genus Homo. (Photo credit: Brian Villmoare)

A camel caravan walks through the excavation site in the Afar region where researchers dug up a partial mandible from a potentially new Homo species. The researchers dated the fossil by looking at the ages of the layers of volcanic ash above and below it. (Photo credit: Brian Villmoare)