New 4 mya anamensis Find In Ethiopia
Rich Travsky
http://news.bbc.co.uk/1/hi/sci/tech/4900946.stm
Fossil hunters have found remains of a probable direct ancestor of humans
that lived more than four million years ago.
The specimens of this ancient creature are helping bridge a long gap during
a crucial phase of human evolution.
Professor Tim White of the University of California, Berkeley, and colleagues
unearthed the cache of fossils in the Middle Awash region of Ethiopia.
They describe the finds, which belong to the species Australopithecus
anamensis, in the journal Nature.
...
When placed together with other fossils from the same general area of
Ethiopia, the 4.1-million-year-old anamensis specimens appear to establish an
evolutionary succession between earlier and later species.
"The fact anamensis is sandwiched between earlier and later hominids is what
is really significant about this Ethiopian sequence," Tim White told the BBC
News website.
The finds close the gap between a more ancient species known as Ardipithecus
ramidus, which is found at 4.4 million years and a later species known as
Australopithecus afarensis, which is present in the Middle Awash 3.4 million
years ago.
Australopithecus anamensis is intermediate between the two not only
chronologically but also in terms of its anatomy.
The anamensis species is not new, but, say the researchers, "this is the
first time that these three species have been shown to be time-successive in
a single place".
...
The fossils represent at least eight individuals and include the largest
hominid canine ever found, the earliest known Australopithecus thigh bone as
well as hand and foot bones.
The excavation at Asa Issie also uncovered the remains of pigs, monkeys and
big cats. The fauna suggest that anamensis was living in a closed, wooded
habitat.
Australopithecus anamensis had a significantly thicker layer of enamel on its
teeth than Ardipithecus, suggesting the later hominid was adapting to eating a
more abrasive diet of roots.
...