Fossils reveal a strong-armed, dead-end hominid

Brawny-limbed human relative walked and climbed trees in East Africa

LIMB BREAKERS The ends of a leg bone (top) and arm bone (bottom) from a 1.34-million-year-old member of Paranthropus boisei were probably chewed off by meat-eating animals. The bones reveal P. boisei had robust arms and legs.

M. Domínguez-Rodrigo et al/PLOS ONE 2013

By Bruce Bower

December 10, 2013 at 11:23 am

A first look at the strapping arms and legs of an unusual member of the human evolutionary family has arisen from new fossil finds at Tanzania’s famous Olduvai Gorge site.

A team led by paleoanthropologist Manuel Domínguez-Rodrigo of Complutense University of Madrid unearthed nine teeth and large parts of two arm bones and two leg bones from an adult male Paranthropus boisei. This hominid, known for having a relatively small brain, big jaws and large teeth at the back of the mouth, lived alongside early Homo species in eastern Africa for about 1 million years before dying out.

Age determinations for volcanic ash layers that border fossil-bearing sediment indicate that this Stone Age hominid lived 1.34 million years ago. Until now, P. boisei fossils dated from around 2.3 million to no earlier than 1.4 million years ago.

Large, powerful limbs enabled P. boisei to both walk upright and at least occasionally spend time in the trees, the scientists report December 5 in PLOS ONE. The ancient Olduvai guy stood just over 5 feet tall and weighed about 136 pounds, the team estimates.