A new basal chaeomysticete (Mammalia: Cetacea) from the Late Oligocene Pysht Formation of Washington, USA

摘要: Modern baleen-bearing mysticetes are descendant from archaic, toothed known the Late Eocene and Oligocene of Pacific Ocean. These mysticetes, such as aetiocetids mammalodontids, dominate fossil record. However, larger bodied eomysticetids have recently been described western Atlantic. lack functional teeth adults thus considered to be earliest members Chaeomysticeti. A new Olympic Peninsula, Washington State, including a partial skull, tympanic bullae, mandibles postcrania, is here Sitsqwayk cornishorum gen. et sp. nov. S. mysticete lacking most phylogenetically basal chaeomysticete. Accordingly, exhibits mosaic aetiocetid eomysticetid characteristics. The presence in North Pacific, its phylogenetic position relative Southern Ocean, suggests possible point origin for