Laetoli
Laetoli is a significant paleontological locality of fossils from the Pliocene in northern Tanzania. It is located in the Rift Valley about 45 kilometers south of Olduvai Gorge and about 200 km west of Arusha, in the Ngorongoro Conservation Area. International attention was the place in 1978, after fossil footprints were discovered by three bipedal individuals of Hominini there. The volcanic ash of this area are reported today than about 3.6 million years old.
The term Laetoli is the reading of Tim White According to a variation of " Olaitole ", the name of a nearby watercourse; According to Mary Leakey, however, it is derived from the usual with the Maasai name for the blood flowers ( Haemanthus ); in the 1970s, the site was also written Laetolil.
History of Research
The today known as Laetoli site is known in professional circles as fossil site since the 1930s, its full meaning for paleoanthropology, however, was not recognized until the 1970s.
The site extends over a distance of about ten kilometers left and right of the river Garusi and is about three miles wide, where the fossils usually emerge on its slopes. Due to the size of this area several dozen find sites ( localities ) have been defined. The predominantly volcanic deposits ( tuff ) are in several places more than 130 feet thick.
Was first scientifically noted was the site in 1935, when Louis Leakey in the Olduvai Gorge worked and was alerted by a local named Sanimu on the fossils from Laetoli. Leakey and his team - including Mary Leakey - spent then a few days in Laetoli and collected various mammalian fossils, including the canine of a primate, but only in 1981 as a hominin ( Australopithecus belonging ) was described previously 44 years unnoticed in the collection of the Natural History Museum ( BMNH M.18773 archive number ) had been detained.
1938/39, then attended the German explorer Ludwig Kohl- Larsen terrain. There he discovered in 1939 among other things, a hominines maxillary fragment with two premolars ( Garusi 1, also: Garusi Hominid 1) and a third maxillary molar ( Garusi 2 ), but without having to assign a new taxon. Have been described: its fossils first time in 1950 by Hans Weinert, which she described as Meganthropus africanus. Later, a canine was in Larsen's collection yet identified as a hominin ( Garusi 4), and all three fossils as the first found fossils of Australopithecus afarensis were finally recognized.
1959 Louis and Mary Leakey returned again after Laetoli back and rallied again mammalian fossils, but discovered no further remains of Hominini; a third visit of the two took place in 1964. Only in 1974, after headed by Mary Leakey in Laetoli, a homininer premolar was discovered (archive LH 1 = Laetoli Hominid 1 ) increased interest in a more thorough exploration of the site, especially since soon discovered several well-preserved mandible of juvenile and adult Hominini were. However, their taxonomic classification initially remained in the dark as there were no reliable data on the age of the fossils. In 1976, 13 newly discovered fossils but was first attributed to an age from 3.59 to 3.77 Millionen years as a result of the conducted Garniss H. Curtis potassium - argon dating. Recent datings were for known until 2010 had become 33 finds an age of about 3.63 to 3.85 million years ago.
1978 started off with Donald Johanson instead of a separate finding from the Afar region the discovered from the Leakey team and first described in Nature, adult mandibular 1976 LH 4 from Laetoli as holotype for the newly described by him in collaboration with Yves Coppens and Tim White Art Australopithecus afarensis from.
The footprints
1976 saw Andrew Hill, a professor of paleontology at Yale University, during a visit to Laetoli in a hamlet on the earth's surface volcanic tuff - called Tuff 7 - depressions, which he called the imprints of the impinging fossil rain drops as well as animal tracks of birds, mammals and invertebrates interpreted. Hill found the tracks when he ducked a lump elephant dung, which a colleague threw at him. 1977 have been discovered in Laetoli additional tracks, which were interpreted with discretion as hominin. In July 1978, the chemist Paul Irving discovered Abell ( member of the team of Mary Leakey ) two parallel traces of doubt bipedal individuals of Hominini who had survived more than 20 meters away. The Western Track comes from a single current hominin individual and initially had 22 marks on, 1979, the neighboring eastern trail of 12 prints as the trail of two was finally consecutively detected in the same lane running individuals: these were the previously oldest evidence of bipedalism in early Hominini. Later, other hominin footprints were secured, so that today around 70 are known. The double track is assigned by many researchers Australopithecus afarensis.
The producers of the tracks - including small monkeys, antelopes, elephants, rhinos, horses, a cat, guinea fowl and a beetle - had taken place about 3.6 million years side by side on fresh and light rain moistened by volcanic ash 20 km away, the volcano Sadiman. The wetted ash from hardened in the sun and was covered by other ash layers.
After completion of scientific investigation, the footprints were covered in 1979 to protect against the weather. 1995/96, the tracks were uncovered again, for fear that the roots of the plants grown on them could destroy the valuable findings. On this occasion, the footprints were again measured, photographed and signed and then sealed again under several layers of sand and soil.
Since 1998, directs Terry Harrison from New York University, further excavations in the area of Laetoli; more than 10,000 fossils were collected, including various Hominini - bones, so also the first discovery of a Paranthropus aethiopicus in Tanzania, whose age is given as 2.66 million years.