PHYLOGENETIC-RELATIONSHIPS OF THE ZIGZAG HERON (ZEBRILUS-UNDULATUS) AND WHITE-CRESTED BITTERN (TIGRIORNIS-LEUCOLOPHUS) ESTIMATED BY DNA-DNAHYBRIDIZATION

Recently, we acquired DNA of two rare species of heron, the Neotropica l Zigzag Heron (Zebrilus undulatus) and the African While-crested Bitt ern (Tigriornis leucolophus). To estimate their phylogenetic relations hips to other herons, we compared these species with representatives o f the major heron clades using DNA-DNA hybridization. Even though the Zigzag Heron resembles a tiger-heron in its barred plumage and forest habitat, it is most closely related to bitterns. The White-crested Bit tern is monophyletic with the New World tiger-herons (Tigrisoma) and, thus, is better termed the White-crested Tiger-Heron. These findings a ccord well with phylogenetic analyses based on osteology. The remainin g uncertainties in higher-level heron phylogeny are principally: (1) t he position and composition of some enigmatic genera (e.g. Gorsachius, Agamia, Pilherodius, and Ardeola); and (2) the identification of the basal heron lineage, which appears to be either tiger-herons or the Bo at-billed Heron (Cochlearius).