FIGURE 2 in Five well-supported fossil calibrations within the "Waterbird" assemblage (Tetrapoda, Aves)

FIGURE 2. Preferred phylogenetic tree based on the phylogenomic analysis of Hackett et al. (2008) showing the family-level relationships (with silhouettes of representatives within each family) within the waterbird assemblage, with five fossil calibrations (Table 1) included. Groups color-coded by membership in traditional avian orders: Pelecaniformes (green), Ciconiiformes (orange), Procellariiformes (blue), Sphenisciformes (brown), Podicipediformes (gold), Gaviiformes (purple). Stratigraphy and associated ages from Cohen et al. (2013; see also Walker et al., 2013). Branches (internodes) outside of fossil calibrations are set to a unit length to make topological relationships clear, and are not intended to represent actual divergence times. Double hash marks indicate that the clade containing Phaethon, Podiceps, and Phoenicopterus is actually recovered as distantly related to the waterbird clade (i.e., it is not its sister-taxon). Nodes that are numbered correspond to fossil calibrations described in the text. Asterisk next to Waimanu manneringi references a vetted calibration from Ksepka and Clarke (2015). Abbreviations: E, Early. M, Middle. L, Late.