Three fossils discovered over the last few years in Kenya have now been identified as ancient members of our genus, Homo. Together, they paint a more complete picture of early Homo as an upright, relatively big-brained African group that encompassed different species with various body types, Science News reports.
A team of Stony Brook University researchers unearthed these fossil hominins (that’s us and our close extinct ancestors) back in 2012 and 2013 from two sites within the Kolom Odiet area of the Turkana Basin in Kenya. These fossil bones belonged to three separate individuals: a near-complete lower jaw (missing only the right central incisor) and two partial skeletons.
Based on the sediment layer they were discovered in, the mandible (KNM-ER 64060) and one of the partial skeletons (KNM-ER 64061) -- which includes some arm bones, the collar bone, and parts of the shoulder blade -- date back to 2.02 to 2.03 million years ago. The arm bones are relatively gracile (or slender), while the cross-section of their cortices are pretty thick. The other incomplete skeleton (KNM-ER 64062) dates back to 1.82 and 1.86 million years ago, and it includes parts of the forearm and right foot. The foot bones show a mix of both primitive (ancestral) and modern (or derived) features. This individual stood at just under a meter-and-a-half tall (or about 4 feet, 7 inches).
All three ancient Kenyans resemble members of early Homo. Specifically the ancient teeth -- with one of the largest canines of any Homo fossil -- probably come from Homo habilis, the earliest member of our genus. (Another Homo habilis fossil, the most complete skull we have of the species, is pictured above.) The partial skeletons likely belonged to Homo erectus.
The findings were presented at the annual American Association of Physical Anthropologists meeting last month.
[Via Science News]
Image: Chip Clark, Smithsonian Institution