Bohaskaia monodontoides, a new monodontid (Cetacea, Odontoceti, Delphinoidea) from the Pliocene of the western North Atlantic Ocean

ABSTRACT

Here we describe Bohaskaia monodontoides, a new taxon of beluga-like odontocete cetacean from the early Pliocene Yorktown Formation of Virginia and North Carolina. Among odontocetes, Bohaskaia shares key characteristics of the rostrum and face with belugas (Delphinapterus leucas), narwhals (Monodon monoceros), and Denebola brachycephala from the late Miocene of Baja California, thus placing it as a member of the Monodontidae. It also displays autapomorphies that merit its placement in a new genus and species. Both Denebola and Bohaskaia occurred in warmer latitudes than those of extant monodontids, even accounting for extralimital records. Such data from the fossil record of Monodontidae indicates that putative cold climate adaptations of living monodontids might have appeared under different environmental conditions and that their Holarctic and sub-Arctic distribution is a relatively recent phenomenon.

ACKNOWLEDGMENTS

We dedicate this paper to Frank C. Whitmore, Jr., in recognition of his ongoing influence and contributions to the study of fossil marine mammals, through generations of students visiting collections at USNM. We also thank the many volunteers and collectors who have collected fossil material from Rice's Pit locality in Virginia over many years. Careful comments and suggestions from O. Lambert, an anonymous reviewer, and Editor J. H. Geisler improved this paper. C. W. Potter and J. G. Mead (USNM) provided access to modern specimens. J.V.J. thanks the WBHR-LSAMP Bridge to the Doctorate Program for financial support during his first two years at Howard University and a National Museum of Natural History predoctoral fellowship from the Smithsonian Institution. We also thank L. G. Barnes and H. Thomas (LACM) for access to specimens and preparation of key anatomical structures on the type specimen of Denebola brachycephala, and L. G. Barnes, T. A. Deméré, and C. S. Gutstein for useful discussions. N.D.P. thanks R. Cavoukian for sharing his lyrical observations on the diving ecology of juvenile Delphinapterus at the Vancouver Aquarium, and L. G. Barrett-Lennard, C. Birdsdale, and the staff at the aquarium for the opportunity to make observations on live Delphinapterus. N.D.P. was supported with funding from the Remington Kellogg Fund and the Smithsonian Institution.

Handling editor: Jonathan Geisler