History of Research in Palaeoanthropology
Beginning of the 20th CenturyEdit
In 1891, Eugene Dubois discovers remains of hominid fossils (which he will call Pithecanthropus) on the island of Java, in southeast Asia. The two main consequences of this discovery:
- stimulated research for a "missing link" in our origins
- oriented research interest toward southeast Asia as possible cradle of humanity
Yet, in South Africa, 1924, Raymond Dart accidentally discovered the remains of child (at Taung) during exploitation of a quarry and publishes them in 1925 as a new species - Australopithecus africanus (which means "African southern ape"). Dart, a British-trained anatomist, was appointed in 1922 professor of anatomy at the University of the Witwatersrand in Johannesburg, South Africa. Through this discovery, Dart:
- documented the ancient age of hominids in Africa and
- questioned the SE Asian origin of hominids, arguing for a possible African origin.
Nevertheless, Raymond Dart's ideas were not accepted by the scientific community at the time because:
- major discoveries carried out in Europe (such as Gibraltar, and the Neander Valley in Germany) and Asia (Java) and
- remains of this species were the only ones found and did not seem to fit in phylogenetic tree of our origins and
- ultimately considered simply as a fossil ape.
It took almost 20 years before Dart's ideas could be accepted, due to notable new discoveries:
- in 1938, identification of a second species of Australopithecine, also in South Africa: Paranthropus (Australopithecus) robustus. Robert Broom collected at Kromdraai Cave the remains of a skull and teeth,
- in 1947, other remains of Australopithecus africanus found at Sterkfontein and Makapansgat, and
- in 1948, other remains of Paranthropus robustus found at Swartkrans, also by R. Broom.
1950s - 1970sEdit
During the first half of the 20th century, most discoveries essential for paleoanthropology and human evolution were done in South Africa.
After World War II, research centered in East Africa. The couple Mary and Louis Leakey discovered a major site at Olduvai Gorge, in Tanzania:
- many seasons of excavations at this site - discovery of many layers (called beds), with essential collection of faunal remains and stone tools, and several hominid species identified for the first time there;
- In 1959, discovery in Bed I of hominid remains (OH5), named Zinjanthropus (Australopithecus) boisei;
- L. Leakey first considered this hominid as the author of stone tools, until he found (in 1964) other hominid fossils in the same Bed I, which he attributed to different species - Homo habilis (OH7).
Another major discovery of paleoanthropological interest comes from the Omo Valley in Ethiopia:
- from 1967 to 1976, nine field seasons were carried out;
- In 1967, discovery of hominid fossils attributed to new species - Australopithecus aethiopicus
- 217 specimens of hominid fossils attributed to five hominid species: A. afarensis, A. aethiopicus, A. boisei, H. rudolfensis, H. erectus, dated to between 3.3 and 1 Million years ago.
Also in 1967, Richard Leakey starts survey and excavation on the east shore of Lake Turkana (Kenya), at a location called Koobi Fora:
- research carried out between 1967 and 1975
- very rich collection of fossils identified, attributed to A. afarensis and A. boisei
In 1972, a French-American expedition led by Donald Johanson and Yves Coppens focuses on a new locality (Hadar region) in the Awash Valley (Ethiopia):
- research carried out between 1972-1976
- in 1973, discovery of most complete skeleton to date, named Lucy, attributed (in 1978 only) to A. afarensis
- more than 300 hominid individuals were recovered
- discoveries allow for a detailed analysis of locomotion and bipedalism among early hominids
From 1976 to 1979, Mary Leakey carries out research at site of Laetoli, in Tanzania:
- In 1976, she discovers animal footprints preserved in tuff (volcanic ash), dated to 3.7 million years ago (MYA).
- In 1978-1979, discovery of site with three series of hominid (australopithecine) footprints, confirming evidence of bipedalism.
1980 - The PresentEdit
Four australopithecine foot bones dated at around 3.5 million years were found at Sterkfontein in 1994 by Ronald Clarke:
- oldest hominid fossils yet found in South Africa
- They seem to be adapted to bipedalism, but have an intriguing mixture of ape and human features
Since then, eight more foot and leg bones have been found from the same individual, who has been nicknamed "Little Foot".
Recent discovery of new A. boisei skull is:
- one of the most complete known, and the first known with an associated cranium and lower jaw;
- It also has a surprising amount of variability from other A. boisei skulls, which may have implications for how hominid fossils are classified.
Recent research suggests that the some australopithecines were capable of a precision grip, like that of humans but unlike apes, which would have meant they were capable of making stone tools.
The oldest known stone tools have been found in Ethiopia in sediments dated at between 2.5 million and 2.6 million years old. The makers are unknown, but may be either early Homo or A. garhi
A main question is, how have these species come to exist in the geographical areas so far apart from one another?
A partial jaw found in Chad (Central Africa) greatly extends the geographical range in which australopithecines are known to have lived. The specimen (nicknamed Abel) has been attributed to a new species - Australopithecus bahrelghazali.
In June 2002, publication of major discovery of earliest hominid known: Sahelanthropus tchadensis (nickname: "Toumai").