We have elsewhere (Graf & Cummings, 2006b) demonstrated the evidence supporting the higher classification of the Unionoida in a phylogenetic context, and that article provides a detailed review of data and methods applied to date to recover the higher-level pattern of cladogenesis of freshwater mussels. Figure 2 depicts a cladogram of the unionoid families based upon our analysis; nodes for which robust phylogenetic tests are wanting are left unresolved. Areas of disagreement based by morphological characters, like the Anodontini (Unioninae) and Lampsilini (Ambleminae) (Graf & Cummings, 2006b). The 61 species of the remaining genera we leave as incertae sedis members of the Ambleminae, representing 18% of the species diversity of the subfamily. We assume, based upon geography and phylogenetic analyses performed to date, that the Amblemi- nae are a monophyletic lineage endemic to North and Central America, including Cuba in the Caribbean. The affinities of these taxa will be resolved as molecular analyses progress and the taxa of the Amblemini Tribe Group are better distinguished with morphological characters.