The Importance of Methods: Archontan Phylogeny and Cladistic Analysis of Morphological Data

Abstract

Perusal of the recent systematic literature leaves the impression that cladistic methodology has contributed little to resolving the relationships between primates and other placental mammals. Despite numerous cladistic analyses, no viable consensus has yet been reached among workers studying morphology (e.g., Novacek and Wyss, 1986; Wible and Novacek, 1988; Pettigrew et al., 1989; Novacek, 1990; Dumont, 1992; Beard, 1993) or molecular data (e.g., Ammerman and Hillis, 1990, 1992; Baker et al., 1991a; Mindell et al., 1991; Adkins and Honeycutt, 1991; Bailey et al., 1992). Most workers agree that primate origins lie somewhere among “archontan” mammals (tree shrews, bats, gliding lemurs, extinct plesiadapiformes), but there is little agreement concerning relationships among these groups and monophyly of Archonta is still an open question (Fig. 1). If cladistic analysis is the powerful tool that we suppose, then why haven’t the relationships of primates been resolved? Part of the answer may lie in the different approaches and methods employed by workers using cladistic methods to address archontan relationships.