|
|||
|
"Long
before it's in the papers" |
|||
|
RETURN TO THE WORLD SCIENCE HOME PAGE Chimp-sized hominid walked upright six million years ago, researchers say Posted
Sept.
2,
2004 Recent fossil evidence, they report, suggests that a hominid, the size of a chimp, walked upright on two legs in Kenya's Tugen Hills, over 6 million years ago --- about 3 million years earlier than "Lucy," the most famous early biped in our lineage.
Robert
Eckhardt,
professor
of
developmental
genetics
and
evolutionary
morphology,
Laboratory
of
Comparative
Morphology
and
Mechanics
(LCMM),
Department
of
Kinesiology
at
Penn
State
University,
was
part
of
a
French
and
American
research
team
responsible
for
analysis
of
the
CT
scans
of
the
internal
structure
of
the
fossil
bone.
Eckhardt
says,
"We
have
solid
evidence
of
the
earliest
upright
posture
and
bipedalism
securely
dated
to
six
million
years."
The
evidence
is
detailed
in
the
current
(Sept.
3)
issue
of
the
research
journal
Science. The
fossil
the
team
studied
is
part
of
a
left
thighbone
unearthed
nearly
four
years
ago
by
Senut
and
Pickford
at
their
dig
in
the
Kenyan
Lukeino
Formation.
The
fragment
includes
the
intact
head
of
the
left
thighbone
--
the
ball
that
is
inserted
into
the
hip
socket
joint
--
plus
the
bony
neck
that
connects
the
ball
to
the
thighbone
shaft
as
well
as
part
of
the
thighbone
shaft.
Measurements
show
that
the
fossil
bone
is
about
the
same
size
as
a
chimpanzee's.
However,
CT
scans
of
the
interior
of
the
bone
reveal
that
the
neck
connecting
the
ball
to
the
shaft
is
thinner
on
top
than
it
is
on
the
bottom,
a
sign
the
researchers
say
that
the
individual
from
which
it
came
walked
on
two
legs.
Eckhardt
says,
"In
present
day
chimps
and
gorillas,
the
thicknesses
in
the
upper
and
lower
parts
of
that
bone
are
approximately
equal.
In
modern
humans,
the
bone
on
top
is
thinner
than
on
the
bottom
by
a
ratio
of
one
to
four
or
more.
The
ratio
in
this
fossil
is
one
to
three."
The ratio in the fossil is evidence for transition to an upright posture and habitual bipedal gait the researchers argue. In addition, Eckhardt notes, because walking upright is the essential mark of a hominid, the ratio is functional evidence that the bones fossilized at Lukeino were from hominids.
|
