Figure 1. This diagram shows the approximate temporal ranges of the main hominid taxa. It assumes that modern humans and the chimpanzees shared a common ancestor; one interpretation of the taxonomy of Pan is given in the right-hand box. The unnamed taxa, marked with a question mark, are based on the informed speculation that there is likely to be as much variety in the early phase of hominid evolution as there is between 3 and 1.5 Ma. Bold dashed lines represent likely evolutionary relationships; dotted lines are even more speculative statements about ancestor–descendant relationships. The left-hand box shows one interpretation of the taxonomy of later Homo.