Laetoli

Laetoli is a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominid footprints, preserved in volcanic ash (Site G). The site of the Laetoli footprints is located 45 km south of Olduvai gorge. Professor Terry Harrison, a physical anthropologist at New York University, has continued research at the site since the late 1990s.

Date

The footprint-bearing layers are Pliocene in age, dated by the K/Ar method to 3.7 million years ago (m.y.a.)."

Hominid footprints

A line of hominid fossil footprints, discovered in May 1976 by Mary Leakey, is preserved in powdery volcanic ash from an eruption of the 20 km distant Sadiman Volcano. Soft rain cemented the ash-layer (15 cm thick) to tuff without destroying the prints. In time, they were covered by other ash deposits. The hominid prints were produced by three individuals, one walking in the footprints of the other, making the original tracks difficult to discover. As the tracks lead in the same direction, they might have been produced by a group -- but there is nothing else to support the common reconstruction of a nuclear family visiting the waterhole together.

	hominid 1	hominid 2
length of footprint	21.5 cm	18.5 cm
width of footprint	10 cm	8.8 cm
length of pace	47.2 cm	28.7 cm
reconstructed body-size	1.34-1.56 m	1.15-1.34 m

The footprints demonstrate that the hominids walked upright habitually, as there are no knuckle-impressions. The feet do not have the mobile big toe of apes; instead, they have an arch (the bending of the sole of the foot) typical of modern humans. The hominids seem to have moved in a leisurely stroll.

Computer simulations based on information from "A. afarensis" fossil skeletons and the spacing of the footprints indicate that the hominids were walking at 1.0 m/s or above, which matches human small-town walking speeds. [cite web |url=http://www.liv.ac.uk/premog/premog-sup-info-Laetoli.htm |title=PREMOG - Supplementry Info |accessdate=2007-11-01 |date= 18 May 2007 |work=The Laetoli Footprint Trail: 3D reconstruction from texture; archiving, and reverse engineering of early hominin gait |publisher=Primate Evolution & Morphology Group (PREMOG), the Department of Human Anatomy and Cell Biology, the School of Biomedical Sciences at the University of Liverpool ]

Footprints of other animals

Other prints show the presence of twenty other animal species, among them hyenas, wild cats (Machairodont), baboons, wild boar, giraffes, gazelles, rhinos, several kinds of antelope, hipparion, buffalo, elephants (of the extinct "Deinotherium" genus), hare and birds. Rainprints can be seen as well. Few footprints are superimposed, which indicates that they were rapidly covered up. Most of these animals are represented by skeletal remains in the area as well."

Human remains

The German anthropologist Ludwig Kohl-Larsen was the first to go to Laetoli to look for fossil remains. In 1934 he found the jaw of "Australopithecus afarensis".Kohl-Larsen, Ludwig (ed.1991). "Ludwig Kohl-Larsen - der Mann der Lucy's Ahnen fand: Lebenserinnerungen und Materialien. Pfälzische Verlagsanstalt; Erich Renner. ISBN 3-87629-173-9]

The remains of 13 hominids have been found, mainly mandibles and teeth. They show affinities to the female skeleton Lucy from Hadar, Ethiopia. Most scholars classify them as "Australopithecus afarensis", but some stress the greater similarity to "Homo" and prefer to speak of "Homo sp. indet."

A rather complete skull found at Ngaloba in 1976 has been dated to ca. 120,000 to 100,000 years ago. It is very modern anatomically, with a cranial capacity of ca. 1200 cm³, but the forehead is still very low."

An account of Leakey's early work at the Laetoli (originally laetolil) site, including the construction of the permanent base camp there in spring 1977, is found in Africa Alone, Odyssey of an American Traveler (August House 1983; Columbus & Company 1988). Sandy McMath, the author, worked as Leakey's camp manager at the time, taking a break from a 2-year trans-continental jeep trek.

Artifacts

No artifacts have been found in the vicinity."

Further reading

* Mary D. Leakey and J. M. Harris (eds), "Laetoli: a Pliocene site in Northern Tanzania" (Oxford, Clarendon Press 1987). ISBN 0-19-854441-3.
* Richard L. Hay and Mary D. Leakey, "Fossil footprints of Laetoli." "Scientific American", February 1982, 50-57."'

References

* [http://encarta.msn.com/media_461543938_761566394_-1_1/Footprints_From_the_Past.html Footprints From the Past]

See also

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

External links

* [http://www.sciam.com/article.cfm?chanID=sa004&articleID=0005C9B3-03AE-12D8-BDFD83414B7F0000 Footprints to Fill : Flat feet and doubts about makers of the Laetoli tracks] - Scientific American Magazine (August 2005)
* [http://www.nature.com/nature/ancestor/pdf/278317.pdf Leakey, M. D. and Hay, R. L. - Pliocene footprints in the Laetolil Beds at Laetoli, northern Tanzania] - Nature
* [http://www.pbs.org/wgbh/evolution/library/07/1/l_071_03.html Laetoli Footprints] - PBS - Evolution
* [http://www.mountainfilm.com/en/2004/film/175/] - film about Ludwig Kohl-Larsen
* [http://www.solwayjonesgallery.com/pr/GSK%20PR%20image.pdf] - artworks for and about Laetoli