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8

January/February 2018^ DISCOVER^19

ANDRZEJ BOCZAROWSKI (2)

❯

ABOUT 5.7 MILLION YEARS

AGO, on what’s now the

Greek island of Crete,

something went for a stroll.

Walking on two legs, its clawless

feet left impressions. Instead of its

first toe sticking out thumblike,

as an ape’s would, this creature’s

big toe was in line with the other

four. This trait and other features

preserved in the ancient prints

are unique to hominins, primates

more closely related to us than to

apes or chimps.

And in an analysis published

in August, researchers concluded

— controversially — that these

footprints at Trachilos, Crete,

appear to belong to a hominin,

walking where none was thought to

set foot until millions of years later.

Other fossilized trackways have

provided valuable insight about

how our lineage evolved to walk

upright, but the oldest currently

accepted hominin trackway, at

Laetoli in Tanzania, is 3.6 million

years old. The Trachilos prints are

about 2 million years older.

The Greek tracks are also

thousands of miles from

eastern Africa, where nearly all

paleoanthropologists believe

hominins — including humans —

evolved. Trachilos study co-author

Per Ahlberg, a paleontologist at

Sweden’s Uppsala University, says

critics have accused the team of

trying to revive a long-debunked

idea that our species evolved in

Europe.

“Some people have suggested

that we are driven by a

Eurocentrism claim. We are

making no claim whatsoever,”

says Ahlberg. “It’s clear modern

humans evolved in Africa.”

Instead, he says, the Trachilos

prints show at least one branch

of early hominins was present in

Europe, and that members of our

family tree were walking efficiently

on two legs more than a million

years earlier than we thought.

“The technical side is well done.

The analysis itself is complex and

sophisticated — they’ve thought it

through,” says William Harcourt-

Smith, a paleoanthropologist at

New York’s Lehman College and

the American Museum of Natural

History. “[But] the devil is in the

details.”

For example, Harcourt-Smith

notes that bears, whose hind

legs do not typically make claw

impressions, were present in this

region at the time, but the team

compared the prints with only a

bear’s forelimb. The lack of claws

is one of the traits cited by the

authors as evidence a hominin

made the prints.

“Bears do rear up and move

bipedally on occasion,” Harcourt-

Smith says. “I’m not saying that’s

what this is, but it was a major

omission not to include hind leg

bear prints for comparison.

“New things get discovered

all the time that challenge old

thinking, and that’s wonderful, but

this is a big claim. It needs to be

properly comparative. It needs to

be better,” he adds.

In a bizarre twist, in mid-

September some of the impressions

were cut from the rock and stolen.

Greek authorities quickly arrested

a man suspected of trying to sell

the prints, which were recovered.

The site is now off-limits, under

a protective cover of tarps and

“a great big heap of rubble,” says

co-author Matthew Bennett of

Bournemouth University, one

of the world’s leading experts

on hominin trackways. Bennett

says research will continue using

the team’s high-resolution digital

scans, a permanent record of the

trackways: “No scientific data has

been lost.”  GEMMA TARLACH

Hominin Trackways

in Greece? The Game

Is Afoot

Trackways on the Greek island of Crete may have been made by a hominin millions of

years before most researchers believe possible, challenging our evolution story.

Is this a 5.7 million-year-old hominin

footprint? A controversial study says yes.