Primate taxonomy, plesiadapiforms, and approaches to primate origins

Abstract

In biology, there is currently a debate being waged about the basic principles of doing taxonomy (e.g., Benton, 2000; Cantino and De Queiroz, 2000; De Queiroz, 1994, 1997; De Queiroz and Gauthier 1990, 1992, 1994; Lee, 1996; Lidén and Oxelman, 1996; Lide7acute;n et al., 1997; Moore, 1998; Nixon and Carpenter, 2000; Pennisi, 1996; Schander and Thollesson, 1995). This debate stems from the common opinion that taxonomy should reflect evolution in some manner, combined with a disagreement about the practical details of how to do this. Although some authors have provided suggestions for making the Linnean system of taxonomy work within the context of a cladistic approach to phylogeny reconstruction (e.g., McKenna and Bell, 1997; Nixon and Carpenter, 2000; Wiley, 1981), others have advocated scrapping the entire Linnean system (De Queiroz, 1994; De Queiroz and Gauthier, 1990, 1992, 1994; Griffiths, 1976), culminating in the dissemination by way of the Internet of a new code for phylogenetic nomenclature, the Phylocode (Cantino and De Queiroz, 2000). Although this document does not yet include guidelines for species taxa, and in spite of the fact that the Phylocode has not yet been "activated" by its authors (as of May, 2003; but see below), there are nonetheless a growing number of instances of the principles codified by this system being applied in real taxonomic practice (e.g., the redefinitions of Mammalia by Rowe, 1988). As such, even if the Phylocode is never adopted or accepted in full, it can still be considered to represent many current ideas about the practicalities of doing taxonomy. In light of these debates a reconsideration of the meaning, content, and status of the taxon name "Primates" seems timely. Anthropologists have sometimes been criticized for ignoring taxonomic principles common to other areas of Biology (e.g., Mayr, 1950; Simpson, 1963), and the fact that the intense debates over taxonomic practice that have been waged in the biological literature in recent years are only rarely reflected in the contemporary anthropological literature suggests that this problem is ongoing. One of the central goals in understanding primate origins must be forming an understanding of where the group lies in relation to non-primate groups, since only against that comparative background can the relative uniqueness of primate features be fully understood. Without such an understanding it is impossible to create plausible adaptive scenarios for why changes occurred in the early evolution of the group. In light of this, it is clear that anthropologists cannot work in a vacuum from current evolutionary and taxonomic practice as applied to other groups of mammals. Thus, it seems prudent to consider how Primates would stand in the context of the new system if the Phylocode were enacted, and how our common conceptions of what this term means could be dealt with in this framework. Even if the Phylocode is never accepted by all, it is worth considering the relative merits of the philosophical position that it represents. This has particular relevance in relation to the inclusion or exclusion of plesiadapiforms from the order Primates, since a determination of whether or not this cluster of extinct forms can be designated as primates depends not only on the supported pattern of relationships but also the taxonomic philosophy being applied. Finally it must be asked whether or not these disagreements over taxonomic approach influence the way in which we do, and should, ask questions about primate origins. © Springer Science+Business Media, LLC 2007.