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A highly significant discovery
Oldest human-like fossil uncovered in South Africa
By Frank Gaglioti
30 December 1998
The discovery of the oldest complete fossilised hominid or
human-like skeleton in South Africa announced on December 9 will
greatly enhance scientific knowledge of evolutionary history by
enabling an unprecedented examination of the bone structure of
a primitive human.
Dr Ron Clarke of Witwatersrand University of South Africa made
the discovery of the 1.2-metre adult Australopithecus (southern
ape) in the Sterkfontein caves near Johannesburg. Australopithecus
is the immediate ancestor of the genus Homo, the biological classification
that includes modern man or Homo sapiens. The skeleton has been
dated at between 3.22 and 3.58 million years old by the Geomagnetism
Laboratory at the University of Liverpool. Previously the oldest
complete hominid skeleton was a 1.5 million-year-old Homo erectus
discovered in Kenya.
The age of the skeleton may prove to be contentious, as it
has been notoriously difficult to date fossil material from South
Africa because of a lack of volcanic ash, which is used in the
most advanced radiometric dating. Donald Johanson, the Director
of the Institute of Human Origins at Arizona State University,
commented that "it may very well be that it is a million
years younger than they say. That should not overshadow the remarkable
importance of a complete specimen like this, so we can really
define what a hominid looks like."
In 1994, Clarke was led to the discovery through the examination
of some stored fossilised bones identified as belonging to the
foot and lower leg of a hominid, which he named "Little Foot".
He followed the clues to the Sterkfontein caves. After a thorough
search, he unearthed more hominid bones, which were found to be
a perfect match with "Little Foot". After careful excavation,
the team discovered that they had a complete skeleton.
The Sterkfontein caves have already proved a veritable treasure
trove of fossilised hominids. It was the site of the discovery
of the 2.6 million-year-old Australopithecus africanus skull known
as "Mrs Ples" as well as numerous other related fossils.
Clarke's discovery was made in a deeper and much older rock stratum.
The analysis of "Little Foot" has already yielded
some valuable insights into the hominid's ability to walk upright.
An examination of its bone structure revealed the creature was
adapted for clutching onto tree branches. Philip Tobias, one of
Clarke's colleagues, said that the hominid had "arboreal
habits coupled with terrestrial habits". His statement has
created considerable controversy, as most anthropologists previously
believed that hominids were completely ground dwelling 3.5 million
years ago.
The current knowledge of Australopithecus has been obtained
from a number of incomplete skeletons and bone fragments. Until
now the oldest most complete Australopithecus was the 3.2 million-year-old
fossil, known as "Lucy," which Donald Johanson discovered
in 1974 in the Hadar valley of Ethiopia.
The discovery of "Lucy" caused a scientific sensation
as it possessed human characteristics such as the ability to walk
upright and use tools but had the brain size of a chimpanzee.
Until then scientists had dismissed the conjecture made by Karl
Marx's collaborator Fredrick Engels last century that upright
stature, freeing the hands for tool making, was the crucial first
step in human evolution--not brain size.
Clarke's find is still partially embedded in the Sterkfontein
cave. Given the delicate and painstaking nature of the work, it
will take another year to complete the excavation. The skeleton
has only just started to yield its full story, which the scientific
community eagerly await.
See Also:
T. H. Huxley and the rise of
modern science
[27 November 1998]
New dinosaur
fossils ignite old controversy
[16 July 1998]
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