Everything about Sahelanthropus Tchadensis totally explained
Sahelanthropus tchadensis is a
fossil ape, thought to have lived approximately 7 million years ago. It is sometimes claimed as the oldest known ancestor of
Homo (
humans) post-dating the
most recent common ancestor of humans and
chimpanzees. It was a species of
Miocene ape, related to humans and other living African apes.
Fossils
Existing fossils, a relatively small
cranium, five pieces of
jaw, and some
teeth, make up a head that has a mixture of derived and primitive features. The braincase, being only 340
cm³ to 360 cm³ in volume is similar to that of extant chimpanzees and is notably less than the approximate human volume of 1350 cm³.
The teeth, brow ridges, and facial structure differ markedly from those found in
Homo sapiens. Due to the distortion that the cranium has suffered, a 3D computer reconstruction hasn't been produced. Since no postcranial remains (bones below the skull) have been discovered, it's as of yet unknown whether
Sahelanthropus tchadensis was indeed bipedal, although claims for an anteriorly placed
foramen magnum suggests that this may have been the case, although some paleontologists have disputed this interpretation of the basicranium. Its canine wear is similar to other Miocene apes.
The fossils were discovered in the desert of
Chad by a team of four; three Chadians, Mahamat Adoum and Ahounta Djimdoumalbaye (who found the skull on
July 19,
2001), Fanone Gongdibe, and Alain Beauvilain, the French team leader. All fossils of
Sahelanthropus were found between July 2001 to March 2002. The discoverers claimed that S. tchadensis is the oldest known human ancestor after the split of the human line from that of chimpanzees. The bones were found in Chad, far from most previous hominin fossil finds, for example Eastern and Southern Africa. However, an australopithecine mandible was also found in Chad by Sahelanthropus' discoverers in
1993 belonging to
Australopithecus bahrelghazali.
Perspective
The fossil skull TM 266, nicknamed "
Toumaï" ("hope of life" in the local
Goran language of Chad), may be a
common ancestor of humans and chimpanzees; most
molecular clocks suggest humans and chimps diverged 1–2 million years after
S. tchadensis (5
mya) but there's now general acceptance among paleontologists, and even among molecularists, that such a late divergence is no longer tenable. The original placement of this species as a human ancestor but not a chimpanzee ancestor complicated the picture of the human family tree. In particular, if Toumaï is a direct human ancestor, then its facial features bring the status of
Australopithecus into doubt because its thickened brow ridges were reported to be similar to those of some later fossil hominids (notably Homo erectus), whereas this morphology differs from that observed in all australopithecines, most fossil hominids and extant humans.
Another possibility is that Toumaï is related to both humans and chimpanzees, but is the ancestor of neither. Brigitte Senut and Martin Pickford, the discoverers of
Orrorin tugenensis, suggested that the features of
S. tchadensis are consistent with a female proto-
gorilla. Even if this claim is upheld, then the find would lose none of its significance, for at present precious few chimpanzee or gorilla ancestors have been found anywhere in Africa. Thus if
S. tchadensis is an ancestral relative of the chimpanzees (or gorillas) then the first light would be shed on their family trees. Furthermore,
S. tchadensis does indicate that the last common ancestor of humans and chimpanzees is unlikely to resemble chimpanzees very much, as had been previously supposed by some paleontologists.
Further Information
Get more info on 'Sahelanthropus Tchadensis'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://sahelanthropus_tchadensis.totallyexplained.com">Sahelanthropus tchadensis Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
