The ancient hominid species that includes ‘Nutcracker Man’ may have made tools – Science News

Paranthropus boisei,
an African hominid that lived between around 2.3 million and 1.2 million years
ago, may have strong-armed its way into stone-tool making with a deft touch.

That’s the implication of the first hand, arm and shoulder
fossils discovered from the same P. boisei
individual, say paleobiologist David Green and colleagues. The fossils suggest
that this extinct species combined powerful arms suited to tree climbing with
grasping hands capable of fashioning stone implements, the researchers
report in the April Journal of Human
Evolution.

P. boisei, a distant cousin to modern
humans, lacked a thick, powerfully gripping thumb characteristic of its hominid
contemporary, Homo erectus (SN: 3/24/15), a prolific maker of
sophisticated stone tools. But the newly described hand bones suggest that P. boisei gripped well-enough to make
and use simple stone and bone tools, just as other
members of the human evolutionary family may have as early as 3.3 million
years ago (SN: 5/20/15). That’s long
before the emergence of the Homo genus,
which appeared around 2.8 million years ago. But reports of tool-making before Homo originated are controversial.

“This is the first evidence that creatures that were almost
certainly not our direct ancestors could have made tools,” says
paleoanthropologist Bernard Wood of George Washington University in Washington,
D.C. “So we can no longer assume — nor should we ever have assumed — that only Homo could make tools,” says Wood, who
was not involved with the new research.

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It’s tempting to argue that only H. erectus, which had a brain approaching twice the average size of
P. boisei’s, could have made
teardrop-shaped, double-edged hand axes that date to around the same time as
the two hominids. Those tools demanded more skill and planning than earlier,
simpler cutting implements. But the case is not closed, says Green, of Campbell
University School of Osteopathic Medicine in Buies Creek, N.C. “We’ll need to
find tools that can be confidently associated with P. boisei and assess its technical abilities before assuming that H. erectus was the superior toolmaker.”

Excavations and surveys from 2004 to 2010 at Kenya’s Ileret
site produced the new P. boisei
finds. Fossils were found in sediment that dates to between about 1.53 million
and 1.51 million years old. Previously excavated 1.5-million-year-old
footprints at Ileret may have been left by H. erectus or P. boisei (SN: 4/16/12).

A large male skull discovered in 1959 is the best-known P. boisei fossil. Dubbed Nutcracker Man,
the individual has wide cheekbones that project forward and a bony crest atop
its braincase that once anchored huge chewing muscles. Nutcracker
Man may have eaten mainly grasses and flowering plants called sedges (SN: 5/2/11).

Suggestions that another member of the Paranthropus genus, P. robustus,
crafted stone tools, based on isolated finger bones
unearthed in South Africa’s Swartkrans cave complex, go back more than 30
years (SN: 5/28/88). Parts
of two arm bones and two leg bones from an adult male P. boisei have turned up since then at Tanzania’s Olduvai Gorge (SN 12/10/13). But the Ileret discoveries
offer the first look at bones from throughout a P. boisei individual’s upper limb. As a result, researchers can
more confidently reconstruct what types of arm and hand movements that hominid
could perform.

Stone artifacts are abundant at ancient Homo sites, a sign that our genus relied far more heavily on
toolmaking than P. boisei did, says
biological anthropologist Neil Roach of Harvard University, who wasn’t involved
in the research. No stone artifacts have been clearly linked to P. boisei fossils.

Intriguingly, Roach adds, the Ileret fossils are relatively
large and thick, suggesting that P.
boisei was more athletic and physically active than typically presumed for
a hominid species that, unlike H. erectus,
probably did not eat meat.