Colloquium paper: reconstructing human evolution: achievements, challenges, and opportunities

Abstract

This contribution reviews the evidence that has resolved the branching structure of the higher primate part of the tree of life and the substantial body of fossil evidence for human evolution. It considers some of the problems faced by those who try to interpret the taxonomy and systematics of the human fossil record. How do you to tell an early human taxon from one in a closely related clade? How do you determine the number of taxa represented in the human clade? How can homoplasy be recognized and factored into attempts to recover phylogeny?

Fig. 1.

Taxa recognized in a typical speciose hominin taxonomy. Note that the height of the columns reflects either uncertainties about the temporal age of a taxon, or in cases where there are well-dated horizons at several sites it reflects current evidence about the earliest (called the first appearance datum, or FAD) and the most recent (called the last appearance datum, or LAD) fossil evidence of any particular hominin taxon. However, the time between the FAD and the LAD is likely to be represent the minimum time span of a taxon, because it is highly unlikely that the fossil record of a taxon, and particularly the relatively sparse fossil records of early hominin taxa, include the earliest and most recent fossil evidence of a taxon. The newest archaic hominin taxon, the ca.1.9 Ma Australopithecus sediba, would occupy the space just above the box for Au. africanus.