Multiple data sets are now available for examining the phylogenetic relationships of certain well-studied taxa. Integrating this information into unified statements of evolutionary history is a major challenge in the field of systematics, with supertree and supermatrix methods emerging as competing strategies for this task. In the su-permatrix approach, all relevant character data are joined into a single data set, and a total evidence analysis of this large matrix is used to test competing phylogenetic hypotheses (Kluge, 1989). In supertree methods, characters first are partitioned into separate data sets, these data sets are analyzed individually, and source trees derived from the preliminary analyses then are combined to yield large synthetic trees (Sanderson et al., 1998). Gatesy et al.(2002) highlighted some problems with previously published supertrees (Purvis, 1995; Bininda-Emonds et al., 1999; Jones et al., 2002) in the context of a recent supertree analysis of mammals (Liu et al., 2001):(1) the supertree data set of Liu et al. included a variety of unnecessary appeals to authority, such as