Discover - USA (2020-01 & 2020-02)

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JANUARY/FEBRUARY 2020. DISCOVER 51

i

A scrap of skull

collected in 1978 and

stored for decades

in an Athens museum may

rewrite the timeline of

when Homo sapiens left our

ancestral African homeland.

In July, a new analysis of

the Apidima 1 fossil, named

for the Greek cave where

it was found more than

40 years ago, suggested it’s

at least 210,000 years old —

the oldest evidence of our

species outside Africa.

The conclusion comes just a year

after a separate team announced

that a partial jaw from Misliya, Israel,

was 177,000 to 194,000 years old.

Along with 120,000-year-old fossils

from China, these recent finds

challenge the long-held notion that

our species did not leave Africa until

about 60,000 years ago.

Unfortunately, all of these

convention-busting fossils are

fragmentary. Apidima 1, for example,

only consists of part of the back of

a skull. However, the piece is telling.

We have a uniquely rounded shape

to the back of our heads — and so

does Apidima 1.

The feature, along with more

subtle anatomical traits, led

researchers to classify Apidima 1 as

H. sapiens despite the incomplete

nature of the find.

Researchers also took a second

look at Apidima 2, another, more

complete skull found nearby back

in the 1970s. They determined that

it belonged to a Neanderthal and

is younger than Apidima 1 by about

40,000 years.

Previous research on the

skull fragments had focused on

the better-preserved specimen,

Apidima 2. Since the two fossils were

found just a foot apart, those same

studies generally assumed that the

skull scraps belonged to the same

species and were of the same age.

According to coauthor Rainer

Grün, speaking at a press conference

in July ahead of the paper’s

publication in Nature, that earlier

research failed to take into account

the location of the fossils: in a

jumbled pile of debris, deposited

over millennia, as material washed

through the cave system.

Said Grün: “It’s a fantastic

coincidence that you have two skulls

together, 30 centimeters apart.”

Skull Is Oldest

Human Fossil

Outside Africa

BY GEMMA TARLACH

23

The U.S. is one

of Earth’s most

volcanically active

countries.

In the last 40 years, there have been

120 eruptions and 52 episodes of

unrest at 44 U.S. volcanoes.

What makes a volcano dangerous?

Current threat levels of

U.S. volcanoes

18 Very high

39 High

49 Moderate

34 Low

21 Very low

Hazards

ash, lava, seismic

events and other

potential volcanic

phenomena

Threat

qualitative risk posed

by a volcano based on

exposure to potential

hazards

Exposure

people, property

and infrastructure,

including aviation, in

harm’s way

Volcanoes by location in U.S.

and its territories

86 Alaska

19 Guam

14 Oregon

12 California

7 Washington state

5 Hawaii

4 Idaho

4 New Mexico

3 American Samoa

2 Arizona

2 Utah

1 Colorado

1 Nevada

1 Wyoming Source: USGS

Above: Digital models (left and center) of the skull

fragment, which is still partly encased in rock (right).

Misliya, Israel

177,000-194,000

years old

Apidima, Greece

210,000 years old

Earliest Homo Sapiens Sites Outside Africa