Final answer:
Sahelanthropus tchadensis lived around 7 million years ago and is considered by some researchers as the last common ancestor of humans and chimpanzees. Its fossil record is crucial to understanding early hominid evolution, despite debates over its place in the human lineage.
Step-by-step explanation:
Temporal Range of Sahelanthropus tchadensis
The fossil record places Sahelanthropus tchadensis, discovered in the Djurab Desert of Chad, within a temporal range of around seven million years ago (7 MYA). The species emerged during a time of significant evolutionary change, near the point where the genetic lineage of humans and chimpanzees split. The sole specimen found, nicknamed "Toumai", combines both primitive and advanced traits and its discovery has implications for our understanding of early hominid evolution. While some researchers propose that Sahelanthropus tchadensis may be the last common ancestor between humans and chimpanzees, this remains a topic of debate due to contrasting molecular and fossil evidence. Nonetheless, its fossilized skull, with a cranial capacity similar to that of a chimpanzee and distinctive features such as a pronounced brow ridge, offers crucial insights into early human ancestry.