fossilized hominin material, but additional complications have come from shifting taxonomic paradigms and nomenclatural practices within the systematics community itself, as well as from continuing debates about phylogenetic methods and species concepts, especially as they apply to fossil material. The net result has been an oft-confusing proliferation of species names and taxonomic realignments for putative human ancestors. To help simplify this imbroglio, Wood compiles, describes, and provides geological dates for all named fossil taxa in the human clade, ranging from anatomically modern Homo sapiens back to various archaic hominins and “possible hominins” that lived several million years ago, and many taxa temporally in between. Wood also addresses several looming opportunities for the field of comparative primate morphology, such as the use of new imaging technologies that should help to clarify (by permitting more detailed levels of examination) when similar anatomical traits in different taxa register genuine homology (shared ancestry) versus homoplasy (evolutionary convergence from separate ancestors).
In Chapter 2, Juan Luis Arsuaga reviews the history of scientific debate, beginning in Darwin’s era, about the precise phylogenetic interrelationships among modern humans and the various great apes of Africa and Asia. Another longstanding debate in anthropology is whether two or more species of more recent human ancestry ever inhabited the planet at the same time (which might seem unlikely based on general ecological considerations for competitive, large-brained primates). Traditionally, fossil-based assessments of this question relied heavily on rather meager population-level data from craniodental anatomy, but more comprehensive morphotypic descriptions are now becoming possible as the available number of known postcranial hominin fossils has swelled as well. Arsuaga reviews these recent fossil-based discoveries about anatomical variation within and among particular proto-human populations dating to more than 0.5 mya, and he concludes that the data are consistent with the more-or-less contemporaneous presence of either different species (depending on one’s definition of species) or, perhaps, morphologically distinct populations within a single species that seems to have been much more polytypic in anatomy than are modern humans.
Increasingly in recent years, the field of physical anthropology has shifted much of its attention from morphology-based appraisals of human evolution to historical reconstructions based on molecular-genetic and genomics data. In Chapter 3, Morris Goodman and Kirsten Sterner review the history of molecular approaches in refining our understanding of primate phylogeny, for example, in revealing the branching orders of lineages that led to extant great apes and humans. They then argue that a modern “phylogenomic approach” can go well beyond phylogeny reconstruction per se by helping to identify Darwinian (positively selected) genetic