Fossil discovery fills gap in human evolution
spiznet
Tim D. White / Brill Atlanta
Teeth and bones from the hand, foot and thigh are among the fragments
of the Australopithecus anamensis fossil found in the Middle Awash
region in northeastern Ethiopia.
By Seth Borenstein
Updated: 1:01 p.m. ET April 12, 2006
WASHINGTON - The latest fossil unearthed from a human ancestral hot
spot in Africa allows scientists to link together the most complete
chain of human evolution so far.
The 4.2 million-year-old fossil discovered in northeastern Ethiopia
helps scientists fill in the gaps of how human ancestors made the giant
leap from one species to another. That’s because the newest fossil,
the species Australopithecus anamensis, was found in the region of the
Middle Awash — where seven other human-like species spanning nearly 6
million years and three major phases of human development were
previously discovered.
“We just found the chain of evolution, the continuity through
time,” study co-author and Ethiopian anthropologist Berhane Asfaw
said in a phone interview from Addis Ababa. “One form evolved to
another. This is evidence of evolution in one place through time.”
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The findings were reported Thursday in the scientific journal Nature.
The species anamensis is not new, but its location is what helps
explain the shift from one early phase of human-like development to the
next, scientists say. All eight species were within an easy day’s
walk of each other.
Until now, what scientists had were snapshots of human evolution
scattered around the world. Finding everything all in one general area
makes those snapshots more of a mini home movie of evolution.
“It’s like 12 frames of a home movie, but a home movie covering 6
million years,” said study lead author Tim White, co-director of
Human Evolution Research Center at University of California at
Berkeley.
“The key here is the sequences,” White said. “It’s about a mile
thickness of rocks in the Middle Awash and in it we can see all three
phases of human evolution.”
Modern man belongs to the genus Homo, which is a subgroup in the family
of hominids. What evolved into Homo was likely the genus
Australopithecus (once called “man-ape”), which includes the famed
3.2 million-year-old “Lucy” fossil found three decades ago. A key
candidate for the genus that evolved into Australopithecus is called
Ardipithecus. And Thursday’s finding is important in bridging — but
not completely — the gap between Australopithecus and Ardipithecus.
Scientists work at the site in northeastern Ethiopia where the fossil
discovery was made. Seven other human-like species spanning nearly 6
million years have been found in the same Middle Awash region.
In 1994, a 4.4 million-year-old partial skeleton of the species
Ardipithecus ramidus — the most recent Ardipithecus species — was
found about six miles from the latest discovery.
“This appears to be the link between Australopithecus and
Ardipithecus as two different species,” White said. The major
noticeable difference between the phases of man can be seen in
Australopithecus’ bigger chewing teeth to eat harder food, he said.
While it’s looking more likely, it is not a sure thing that
Ardipithecus evolved into Australopithecus, he said. The finding does
not completely rule out Ardipithecus dying off as a genus and
Australopithecus developing independently.
The connections between Ardipithecus and Australopithecus have been
theorized since an anamensis fossil was first found in Kenya 11 years
ago. This draws the lines better, said Alan Walker of Penn State
University, who found the first anamensis and is not part of White’s
team.
Rick Potts, director of the Smithsonian’s Human Origins Program,
agreed: “For those people who are tied up in doing the whole human
family tree, being able to connect the branches is a very important
thing to do.”
© 2006 The Associated Press. All rights reserved. This material may
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Dar Habel
spiznet wrote:
> We just found the chain of evolution, the continuity through time'
> Tim D. White / Brill Atlanta
>
> Teeth and bones from the hand, foot and thigh are among the fragments
> of the Australopithecus anamensis fossil found in the Middle Awash
> region in northeastern Ethiopia.
The full article appears in the 13 April 2006 issue of Nature, and
appears to be free for all to download in html or pdf from:
http://www.nature.com/nature/journal/v440/n7086/full/nature04629.html
At least today,
Dar
rmacfarl
spiznet wrote:
> We just found the chain of evolution, the continuity through time'
> Tim D. White / Brill Atlanta
> Rick Potts, director of the Smithsonian's Human Origins Program,
> agreed: "For those people who are tied up in doing the whole human
> family tree, being able to connect the branches is a very important
> thing to do."
Ain't that the truth! Pass the grains of salt please - a story of 4
million years' continuity in 1 small place smacks of wish projection,
don't you reckon?
Exciting stuff though - but where's the Ardipithecus monograph???
Ross Macfarlane
spiznet
Ross-
"This appears to be the link between Australopithecus and
Ardipithecus as two different species," White said. The major
noticeable difference between the phases of man can be seen in
Australopithecus' bigger chewing teeth to eat harder food, he said.
While it's looking more likely, it is not a sure thing that
Ardipithecus evolved into Australopithecus, he said. The finding does
not completely rule out Ardipithecus dying off as a genus and
Australopithecus developing independently.
-Tim White
This is as far as he's willing to go in this article. maybe saving the
good stuff?
-Mark
rmacfarl
Saving it since 1994? Bloody Mary's phantom pregnancy didn't last that
long.
White et al announced Ardipithecus in '94 in a blaze of publicity.
Since then, no one else has seen the fossils up close, & White has
still yet to produce a detailed monograph on them - & yet White et al
continue to issue pronouncements which include the a priori assumption
that Ardipithecus is indeed a valid generic designation.
It smacks of Dead Sea Scrolls - a small clique who produce data on a
drip feed spread over decades, but won't allow anyone outside the
clique to access the source material.
Show me the money Tim!
Ross Macfarlane
Dar Habel
I'm with you all the way on this, Ross.
> White et al announced Ardipithecus in '94 in a blaze of publicity.
White, T.D., Suwa, G. and Asfaw, B., 1994. Australopithecus ramidus a
new species of early hominid from Aramis, Ethiopia: Nature, 371:
306-312.
WoldeGabriel, G., White, T. D., Suwa, G., Renne, P., de Heinzelin, J.,
Hart, W. K. and Helken, G., 1994. Ecological and temporal placement of
early Pliocene hominids at Aramis, Ethiopia. Nature, 371: 330-333.
and a corrigendum a year later, changing the taxon to Ardipithecus
ramidus.
White, T. D., Suwa, G. and Asfaw, B., 1995. Corrigendum:
Australopithecus ramidus new species of early hominid from Aramis,
Ethiopia. Nature, 375: 88.
> Since then, no one else has seen the fossils up close, & White has
> still yet to produce a detailed monograph on them - & yet White et al
> continue to issue pronouncements which include the a priori assumption
> that Ardipithecus is indeed a valid generic designation.
I agree, that's been the White et al. agenda since discovery.
Interestingly, the 1995 corrigendum changing the taxon to Ardipithecus
also served as the announcement of the December 1994 discovery at
Aramis of more material including a partial skeleton thought to be of
the same type individual (A. ramidus). Even less is known of this
partial skeleton than what scant information was published by Nature
in 1994, BUT, some of the December 1994 material seems to have made a
re-appearance with this new paper. In Supplementary Table 1 of White
et al. 2006, "Hominid fossils", ARA-VP14-1, a left and right maxilla,
discovered at Aramis 11/13/94 (that's the date given on the
supplementary table 1), is now listed right alongside the Asa Issie
specimens as Australopithecus anamensis. The explanation for this is
that ARA-VP-14-1 was found at a higher stratographic level (~80m above)
at Aramis (site 14), now dated at 4.1-4.2 myr BP (as is Asa Issie),
than were the ramidus fossils found in the "Lower Aramis Member
strata", dated ca. 4.4 myr BP. OK, but what about the "partial
skeleton" announced in the 1995 corrigendum. I think White owes us
some explanation for the whereabouts and progress made on these
"December 1994" discoveries. Ron Clarke has given us more information
on the StW-573 skeleton from Sterkfontein, almost immediately, even
though the skeleton was not even yet removed from the cave matrix when
Clarke published his preliminary reports. I see no reason why White
refuses to at least offer a similar preliminary report on A. ramidus
ramidus.
> It smacks of Dead Sea Scrolls - a small clique who produce data on a
> drip feed spread over decades, but won't allow anyone outside the
> clique to access the source material.
Again, I agree.
Dar
J. Bahl
"Dar Habel" <Dar_...@yahoo.com> wrote in message
news:1144987119.0...@g10g2000cwb.googlegroups.com...
I wonder what White's motives are for waiting so long to publish? To me, it
seems to go against the whole concept of scientific inquiry aand the free
exchange of ideas. Pity.
John