A jawbone fossil, steps from where it was sighted by Chalachew Seyoum, an ASU graduate student from Ethiopia, is pictured in Afar Regional State, Ethiopia in this undated handout photo courtesy of ... more 
A jawbone fossil, steps from where it was sighted by Chalachew Seyoum, an ASU graduate student from Ethiopia, is pictured in Afar Regional State, Ethiopia in this undated handout photo courtesy of Arizona State University/Kaye Reed . Scientists said on March 4, 2015 the fossil represents the oldest known representative of the human genus Homo and appears to be a previously unknown species from the human lineage's earliest phases. REUTERS/Arizona State University/Kaye Reed/Handout via Reuters (ETHIOPIA - Tags: SCIENCE TECHNOLOGY ENVIRONMENT) ATTENTION EDITORS - NO SALES. NO ARCHIVES. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS less 
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Reuters | Photo By HANDOUT / Reuters
Wed, Mar 4, 2015 1:03 PM EST