The Ethiopian fossils Ardipithecus ramidus "the root of terrestrial apes" is a hominid Ethiopian old female from 4.4 million years reminds us that our distant origins. The fossil, discovered in 1994, is also a star of paleoanthropology, along with Lucy, and Orrorin Toumai.
11 articles, signed by 47 scientists (paleontologists, paleoanthropologists, biochemists, geologists, and paleobotanists) worldwide have been published in the journal Science October 2, 2009.
He had patiently cleaning the fossils before researchers can scan them to see the inside of bones. The name Ardipithecus ramidus from the Afar language in which Ardi means "soil" and Ramid "root", pithecus is derived from the Greek word "monkey".
Its main measurements and its practice of bipedalism, related to the human branch. His brain (between 300 and 350 cm3) was comparable to that of modern chimpanzees or female bonobo. The studies cover 36 different individuals found around the first fossil skeleton but the most complete (45% of the total skeleton) is Ardi with 125 different bones (skull fragments, teeth, arm bones, hand and wrist, pelvis, legs and feet). Ardipithecus ramidus hominid is the best documented before the advent of Australopithecus there are 4 million years. The Ardipithecus kadabba (5.6 million years), or Orrorin tugenensis (6 million) and Sahelanthropus tchadensis (7 million), are known only through a few dozen bones.
What like this distant ancestor?
Ardi weighed about 50 kg and measured 1.20 m, details and Tim White of UC Berkeley and co-director of the Middle Awash project, which is a lot for a hominid as old. By comparison Australopithecus afarensis Lucy, discovered 75 km away from Aramis and who lived more than a million years later, weighed only 25 kg.
Ardi evolved in a tropical clear with palm trees, hackberry trees and fig trees, including elephants, rhinos, giraffes and other antelopes.
The information has been obtained through phytolites, which accumulate in and around plant cells.
"Unlike pollens, phytolites are resistant to oxidation in soils, making them good markers of the vegetation at the time of the earliest hominids," explains Raymonde Bonnefille and Doris Barboni of the European Research Center and d teaching of Environmental Geosciences (Cerege), located in Aix-en-Provence.
"On the ground, Ardi walked on two legs, as evidenced by the shape of its basin, detailing Tim White. But his big toe entirely effective against other toes, and arch, very flat, forbade long walks and running.
In trees, Ardi was certainly less agile and fast as chimpanzees, his hand does not have the adaptations specific to monkeys, like a palm and some very elongated ligaments allowing the suspension to the branches.
" The teeth are smaller and thinner than in monkeys, could be used as weapons to Ardipithecus males to attack others, as is the case in primates.
"The males were probably matched to one female, did not like competing in the monkeys access to several partners, explains Owen Lovejoy of Kent State University. Perhaps males did they bring food to females. "
Ardipithecus upsets many certainties.
"Based on the genetic proximity between chimpanzees and modern humans, it was thought that the earliest hominids would resemble chimpanzees, says Owen Lovejoy. Ardipithecus and contradicts the theory tells us that certain traits specific to chimpanzees, as their aggressive social behavior, emerged after the separation of our two lines. "
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Image: On December 18, 2009, coverage of the journal Science has shown that gentle face and enigmatic Ardi, or Ardipithecus ramidus. Ardipithecus is both bipedal and arboreal. the creature probably resembled a chimpanzee more than a man. The most famous fossils are those of Australopithecus "Lucy", a female skeleton discovered in Ethiopia in the 1970s. The australopithecines have led to the human lineage. Ardipithecus may therefore represent an earlier stage on the path that leads to humans.
Ardi he lived 4.4 million years ago in Ethiopia. Ardipithecus is an extinct genus of the tribe Hominini order Primates. His brain (≈ 300 to 350 cm3) is much smaller than the brains of australopithecines like Lucy (≈ 400 to 550 cm3).
The fossil "Lucy," a female skeleton discovered in Ethiopia in the 1970s, are more famous than Ardi. Ardi teeth suggest it was an omnivorous and frugivorous with a regime that does not depend on hard foods or abrasives.
Ardipithecus was updated in the sands of the Valley of the Awash, site of Aramis, 230 km northeast of the Ethiopian capital Addis Ababa.
It is the researcher Ethiopian Yohannes Haile-Selassie, member of the Middle Awash Paleoanthropological Research Project has identified land in the bones of his hand, November 11, 1994.
The studies cover 36 different individuals found around the first fossils discovered in Ethiopia, but the most complete skeleton (45% of the total skeleton) is Ardi with 125 different bones (skull fragments, teeth, arm bones, hand and wrist, pelvis, legs and feet). Researchers have recreated the environment of Ardipithecus and have lived in a forest when he was already walking.
Indeed Ardi evolved in a tropical clear of Ethiopia, with palm trees, hackberry trees and fig trees, including elephants, rhinos, giraffes and other antelopes.
Other fossils found at the site show that Ardi lived alongside monkeys, rats, moles and other grazing animals like cows.
Professor White and his colleagues, Gen Suwa and Berhane Asfaw discovered the fossils in the Middle Awash of Ethiopia in the middle of the Rift Valley.
The fossil hunters working in Ethiopia have unearthed the remains of at least nine primitive hominids that are between 4.5 million and 4.3 million years.
All these discoveries are of the same species, Ardipithecus ramidus, described in 1995. These tests show the abundance of trees, estimated between 40 and 65% of the plant landscape of Ardi.
The theory of bipedalism, which requires an adjustment to the transformation of a community woodland in open savanna, in this case to reconsider because Ardipithecus rebounded in a semi-wooded landscape. whether Ardipithecus is not our ancestor, it is a possible first representatives of the human lineage.
Image: Ardipithecus lived about 4.4 million years ago in Ethiopia, in a tropical clear.
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