Laetoli
From Wikipedia, the free encyclopedia
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.
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[edit] Date
The footprint-bearing layers are Pliocene in age, dated by the K/Ar method to 3.7 million years ago (m.y.a.).
[edit] The footprints
A line of hominid fossil footprints, discovered in 1978 by Mary Leakey, Richard Hay, Tim White and their team, 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.[1]
[edit] 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. Traces of raindrops can be seen as well. Few prints are superimposed, which indicates that they were rapidly covered up again. Most of these animals are represented by skeletal remains in the area as well.
[edit] 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.[2]
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.
[edit] Artifacts
No artifacts have been found in the vicinity.
[edit] 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.
[edit] References
- ^ PREMOG - Supplementry Info. The Laetoli Footprint Trail: 3D reconstruction from texture; archiving, and reverse engineering of early hominin gait. Primate Evolution & Morphology Group (PREMOG), the Department of Human Anatomy and Cell Biology, the School of Biomedical Sciences at the University of Liverpool (18 May 2007). Retrieved on 2007-11-01.
- ^ 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
[edit] See also
- List of fossil sites (with link directory)
- List of hominina (hominid) fossils (with images)
[edit] External links
- Footprints to Fill : Flat feet and doubts about makers of the Laetoli tracks - Scientific American Magazine (August 2005)
- Leakey, M. D. and Hay, R. L. - Pliocene footprints in the Laetolil Beds at Laetoli, northern Tanzania - Nature
- Laetoli Footprints - PBS - Evolution
- [1] - film about Ludwig Kohl-Larsen
- [2] - artworks for and about Laetoli
