A late Miocene ziphiid (<i>Messapicetus</i>sp.: Odontoceti: Cetacea) from the St. Marys Formation of Calvert Cliffs, Maryland

Abstract

The vast majority of the more than 600 species that have been identified from the Miocene sediments of Calvert Cliffs, Maryland (Fig. 1), are of marine organisms. The biota includes palynomorphs, terrestrial plants, diatoms, dinoflagellates, foraminiferans, sponges, annelid worms, corals, abundant and diverse mollusks, ostracods, decapod crustaceans, barnacles, an inarticulate brachiopod, echinoderms, sharks and rays, bony fishes, turtles, crocodiles, pelagic birds, seals, sea cows, isolated and fragmentary remains of large terrestrial mammals, and a diverse assemblage of approximately 30 species of both odontocetes and mysticetes (Gottfried et al., 1994). In terms of vertebrate remains, those of cetaceans are second only to the number of chondrichthian teeth that erode from the length of Calvert Cliffs and their extensions out under the waters of the Chesapeake Bay. The three Miocene formations comprising Calvert Cliffs (Fig. 2) differ in their cetacean assemblages. The Lower Miocene to lower Middle Miocene (Burdigalian and Langhian) Calvert Formation has long been known to preserve one of the world's richest and most diverse extinct cetacean assemblages. Of the 19 recognized odontocete species from the Chesapeake Group, 12 are known exclusively from the Calvert Formation and another three are derived from both the Calvert and the Middle Miocene (Serravallian) Choptank formations (to date, no odontocete spe