Laetoli

'''Laetoli''' is a site in [[Tanzania]], dated to the [[Plio-Pleistocene]] and famous for its [[hominin]] footprints, preserved in [[volcanic ash]] (Site G). The site of the '''Laetoli footprints''' is located 45 km south of [[Olduvai gorge]]. [[Image:Laetoli.jpg|frame|Laetoli Site, February 2006]] ==Date== The footprint-bearing layers are [[Pliocene]] in age, dated by the [[Potassium-argon dating|K/Ar method]] to 3.5 million years ago ([[mya (unit)|m.y.a.]]).'' ==Hominin footprints== A line of [[Hominidae|hominid]] [[trace fossil|fossil]] footprints, discovered in 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.

	hominin 1	hominin 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 [[fossil trackway|footprint]]s 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 hominins 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 walking speeds. The results of other studies have also supported a human-like gait. ==Footprints of other animals== Other prints show the presence of twenty other animal species, among them [[hyena]]s, wild cats ([[Machairodus]]), [[baboon]]s, [[wild boar]], [[giraffe]]s, [[gazelle]]s, [[Rhinoceros|rhino]]s, several kinds of [[antelope]], [[hipparion]], [[African Buffalo|buffalo]], elephants (of the extinct ''[[Deinotherium]]'' genus), [[hare]] and [[bird]]s. 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 [[skeleton|skeletal]] remains in the area as well.'' ==Hominin 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]]''. The remains of 13 [[Hominidae|hominid]]s have been found, mainly [[mandible]]s and [[teeth]]. They show affinities to the female skeleton [[Australopithecus afarensis|Lucy]] from [[Hadar, Ethiopia]]. Most scholars classify them as ''[[Australopithecus afarensis]]'', but some stress the greater similarity to ''[[homo (genus)|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). ==Artifacts== No [[Artifact (archaeology)|artifact]]s have been found in the vicinity, at least within the ancient Laetolil Beds that contain the trackway. Artifacts from the younger Olpiro and Ngaloba Beds, also preserved at Laetoli, have been found.'' ==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.''' == See also == *[[List of fossil sites]] ''(with link directory)'' *[[List of hominina fossils|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 *[http://www.webcitation.org/5kwsY24mV Footprints From the Past] 2009-10-31) {{coord missing|Tanzania}}