Sahelanthropus tchadensis is the species name given to a cranium and some jaw and tooth fragments believed to be about seven million years old, which may be the remains of an as-yet-unknown early hominid species. They were discovered in Chad in 2001.
- Fossil Remains -
In 2001, Ahounta Djimdoumalbaye found a cranium (skull), jaw fragments, and teeth in the southern Sahara Desert, in the country of Chad. The remains were nicknamed "Toumai," it being common to assign an individual name to ancient hominid fossils (Toumai's name is taken from "hope of life" in Dazaga, a Chad language). Toumai was then extrapolated to be representative of an as-yet-undiscovered species of very early hominids, Sahelanthropus tchadensis.
Sahelanthropus, if Toumai is any indication, had a relatively undeveloped brain, one which resembled those of chimpanzees today. They also had notably small canine teeth, a flat face, and large brow ridges. The existing skull has suffered considerable damage and was unaccompanied by any remains of Toumai's body, and therefore the ability to piece together much more in detail is very limited.
- What Sahelanthropus Might Have Been Like -
It is also as yet unclear whether Sahelanthropus was bipedal (i.e. walked on two legs); if so, it would push the history of bipedalism millions of years farther back into the human past than previously suspected. (Currently it is believed that the transition was underway several million years farther into the future, during the early years of the Australopithecus genus.) Either way, if Sahelanthropicus can be conclusively linked to the later hominids which were the ancestors of humans, this would become one of our first known ancestors. It might even be so far back that it was before the division between today's humans and chimpanzees occurred, although if it was, then Sahelanthropicus almost certainly was not bipedal.
The situation is further complicated by the discovery the previous year (in 2000) of a specimen of another species called Orrorin tugenensis, which, at roughly six million years old, is about a million years younger than Sahelanthropus tchadensis. Orrorin, too, shows some indications of having walked bipedally, but it survives only via a few bone fragments. If Orrorin was bipedal, then Sahelanthropus clearly could be bipedal as well (although it wasn't necessarily so). That would mean that the previous century's assumption that the Austrlopithecines (like the famous Lucy) were our direct ancestors, purely on the basis of their being the earliest known primates to stand erect, would be thrown out the window: the australopithecines would become either a series of intermediate species, or perhaps even an unrelated set of extinct cousins, not directly related to today's human beings at all.
Even if Sahelanthropus tchadensis is ultimately ruled out as an ancestor of humans, it could still be an ancestor of other primates, like the gorilla or the chimpanzee. This too would be of interest to zoologists and primatologists (if not human paleoarchaeologists), because the evolutionary picture of those species is really not much clearer than our own. Moreover, the discovery of Sahelanthropus tchadensis reminds us how little we still know about the early history of the hominids which led to ourselves today.