Heyning, J. E. 1997 Sperm whale phylogeny revisited: analysis of the morphological evidence Marine Mammal Science 13 596-613 Probiscidea Artiodactyla Perissodactyla Balaenopteridae Balaenidae Neobalaenidae Eschrichtiidae Physteridae Ziphiidae Platanistidae Iniidae Monodontidae Phocoenidae Delphinidae Osteology Maximum Parsimony Based on reanalysis of the original matrix. Heyning_1997a