Murakami, Shimada, Hikida & Hirano 2012. TWO NEW EXTINCT BASAL PHOCOENIDS (CETACEA, ODONTOCETI, DELPHINOIDEA), FROM THE UPPER MIOCENE KOETOI FORMATION OF JAPAN AND THEIR PHYLOGENETIC SIGNIFICANCE. Journal of Vertebrate Paleontology, 32(5) 2012: 1172-1185