Section 20.2 mentions that there is debate over the evolutionary affinities of Sahelanthro...

Section 20.2 mentions that there is debate over the evolutionary affinities of Sahelanthropus tchadensis. Given the age and appearance of the skull in Figure, there are many possibilities: It could be our common ancestor with the chimpanzees; it could be a species more closely related to us than to the chimpanzees; it could be a species more closely related to the chimpanzees than to us; it could even be a species more closely related to gorillas than to either the chimpanzees or us. Suppose you are a paleoanthropologist who wants to figure out which of these possibilities is correct. What strata would you choose to search for more fossils? If you are lucky enough to find a skull, what features would tell you which hypothesis is closest to the truth?

Figure A possible early hominin This 6- to 7-millionyear-old skull, found by a member of a team led by Michel Brunet, may represent a close relative of our common ancestor with the chimpanzees. From Wood (2002).