Final answer:
Sahelanthropus tchadensis was discovered in Chad, West Africa. This species lived around seven million years ago and provides insight into the complex evolutionary history of hominins, coinciding with the period when humans and chimpanzees diverged.
Step-by-step explanation:
Sahelanthropus tchadensis, known as Toumai, was found in Chad in West Africa. Discovered in 2001-2002 by a team led by French paleoanthropologist Michel Brunet, the species dates back nearly seven million years ago. This discovery placed Sahelanthropus tchadensis at the cusp of the divergence from the common ancestor of humans and chimpanzees, which took place between 5 to 7 million years ago. The fossil is notable for its small cranial capacity similar to that of a chimpanzee, and traits such as a large brow ridge.Comparisons with other hominin fossils, such as Australopithecus africanus, Australopithecus afarensis, and Australopithecus sediba, demonstrate the complex evolutionary history of the hominins. These discoveries, along with the Toumai fossil, contribute to our understanding of human evolution, even as they sometimes provoke debate among researchers concerning the ancestry of modern humans.