AL 129-1

Infobox fossil


catalog number = AL 129-1
species = "Australopithecus afarensis"
age = 3-3.2 mya
place discovered = Hadar, Ethiopia
date discovered = 1973
discovered by = Donald Johanson

AL 129-1 is the fossilized knee joint of the species "Australopithecus afarensis". It was discovered in Hadar, Ethiopia by Donald Johanson in November 1973. [harvnb|Johanson|1981|p=154] cite web
last = Johanson
first = Donald
authorlink =Donald Johanson
title =Lucy's Knee Joint, Letter from Donald Johanson, August 8, 1989
publisher =TalkOrigins Archive
date= 1989
url =http://www.talkorigins.org/faqs/knee-joint/johanson1.html
accessdate =2007-06-03 ] [cite web
last = Foley
first =Jim
title =Prominent Hominid Fossils
publisher =TalkOrigins Archive
date= 2004
url =http://www.talkorigins.org/faqs/homs/specimen.html#al129-1
accessdate = 2007-06-03
cite web
last = Foley
first =Jim
title =Biographies: Donald Johanson
publisher =TalkOrigins Archive
date= 1998
url =http://www.talkorigins.org/faqs/homs/djohanson.html
accessdate = 2007-06-03 ]

It is estimated to be 3-3.2 million years old.Fact|date=November 2007

Its characteristics include an elliptical Lateral condyle and an oblique femoral shaft like in humans, indicating bipedalism.

Discovery

French geologist Maurice Taieb discovered the Hadar Formation in 1972. He then formed the IARE, inviting notably Johanson, an American anthropologist now head of the Institute of Human Origins of Arizona State University, and Yves Coppens, a French born paleontologist now based at the Collège de France to co-direct the research. An expedition was formed with four American and seven French participants, and in the Fall of 1973 the team surveyed Hadar, Ethiopia for fossils and artifacts related to the origin of humans. [harvnb|Johanson|1981|p=154-158]

They found numerous fossils, but at first no hominids. Then in November 1973, near the end of the first field season, Johanson kicked at what he thought was a hippopotamus rib and found that it was actually a fossil of a proximal tibia, the upper end of a shinbone. From its small size he thought it was a monkey, and decided to collect it. While he was writing it up, he noticed a few yards away a distal femur, the lower end of a thighbone, This was split so that it had only one of the condyles, or lumps making the knee joint. However, the other condyle lay next to it, and when he fitted them together and fitted them to the proximal tibia, the angle that the femur and tibia formed at the knee joint clearly showed that this was an upright walking hominid, unlike a monkey which has the femur and tibia forming a straight line. Tom Gray walked up, and shown the tibia on its own thought it was a monkey, but when shown the angle formed with the tibia agreed that this was from a hominid. [harvnb|Johanson|1981|p=159-160]

This was an immensely important find, as it would be the first showing upright walking hominids from 3 million years ago. On the day after finding the fossil Johanson was beginning to doubt his certainty, and there was an urgent need for confirmation as their agreement with the Ethiopian government required them to describe the finds at a press conference before they left. He did not want to botch his first important fossil interpretation, but they would not be allowed to take the fossil away for study unless he gave a description. That second evening he remembered a nearby ruin of an Afar burial mound. Comparison of the fossil finds with modern bones exposed by the collapsed side of the mound showed that, except for size, the bones were indeed virtually identical. [harvnb|Johanson|1981|p=161-163]

The team returned for the second field season in the following year and found hominid jaws. Then, on the morning of November 30, 1974, Johanson and Gray were searching in a gully about two and a half kilometres from the site where the knee joint had been discovered, when Gray found the first fossil fragment of Lucy (Australopithecus).

See also

*List of fossil sites "(with link directory)"
*List of hominina (hominid) fossils "(with images)"

Further reading

*Johanson, D. C. and T. Taieb, 1976. "A preliminary anatomical diagnosis of the first plio/pleistocene hominid discoveries in the central Afar, Ethiopia." Am. J. Phys. Anthropol. 45: 217-234.
*

References

External links

*cite web | title=Images of AL 129-1 | url=http://www.mnh.si.edu/anthro/humanorigins/ha/al129.htm | accessdate=2006-07-12