Big Woman with a Distant Past: Stone Age gal embodies humanity's cold shifts

From: Janice Matchett <janmatch@earthlink.net>
Date: Sat Feb 25 2006 - 15:29:58 EST

Note to self: Quote for future reference:

"Some researchers had previously dubbed this
ancient individual a male solely on the basis of
its large, thick-boned skull."

~ Janice :)

Big Woman with a Distant Past: Stone Age gal embodies humanity's cold shifts
Science News ^ | Bruce Bower
http://www.sciencenews.org/articles/20060225/fob3.asp

A 260,000-year-old partial skeleton excavated in
northwestern China 22 years ago represents our
largest known female ancestor, according to a new
analysis of the individual's extensive remains.

This ancient woman puts a modern twist on Stone
Age human evolution, say Karen R. Rosenberg of
the University of Delaware in Newark, Lü Zuné of
Peking University in Beijing, and Chris B. Ruff
of Johns Hopkins University School of Medicine in
Baltimore. The fossil individual's large size and
the apparent adaptation of her body to cold
conditions are "consistent with the idea that
patterns of human anatomical variation that we
see today have deep evolutionary roots," Rosenberg asserts.

Although the woman belonged to the Homo genus,
her species is uncertain. Now known as the
Jinniushan specimen, she stood roughly 5 feet,
5-1/2 inches tall and tipped the scales at 173
pounds, the three anthropologists estimate. The
only Stone Age Homo woman known to have
approached that size weighed an estimated 163
pounds. Her partial skeleton came from a
100,000-year-old Neandertal site in France.

The Jinniushan specimen's size reflects her
membership in a population that, as an adaptation
for retaining heat in a cold climate, evolved
large, broad bodies with short limbs, a shape
similar to that of near-polar populations today,
the scientists propose in an upcoming Proceedings
of the National Academy of Sciences.

The large estimated brain size of the Chinese
fossil supports a current theory of mid–Stone Age
brain expansion in Homo species, the researchers
say. Earlier analyses of other fossils' skulls
and lower-body bones­not including multiple bones
from single individuals­had indicated that,
between 1 million and 200,000 years ago, the Homo
lineage peaked in body size and displayed
considerable brain growth relative to body size.

Bones of the Jinniushan specimen include a skull
with many upper-jaw teeth, six vertebrae, two
left ribs, a left-forearm bone, and the left half of the pelvis.

Pelvic shape and proportions are those of a
female, the researchers conclude. Some
researchers had previously dubbed this ancient
individual a male solely on the basis of its large, thick-boned skull.

Three other partial-fossil individuals found in
high-latitude, mid–Stone Age sites­two
Neandertals and one of another Homo species­had
wide torsos and short limbs, although to a lesser
extent than the Jinniushan specimen did, Rosenberg says.

The Chinese skeleton's age estimate derives from
measurements of radioactive material that
accumulated in animal teeth found in the same sediment.

The new findings reinforce previous fossil
analyses suggesting that mid–Stone Age human
ancestors evolved cold-adapted bodies at lower
latitudes and in warmer climates than modern
people did, remarks anthropologist Erik Trinkaus
of Washington University in St. Louis.

In his view, that's because mid–Stone Age folk
had less effective ways to protect themselves
from the cold than people did after about 60,000
years ago. At that time, campfires gave way to
stone-lined hearths. The nature of mid–Stone Age
clothing and shelter is unknown, Trinkaus adds.
Received on Sat Feb 25 15:31:23 2006

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