A new kentriodontid dolphin (Cetacea; Delphinoidea) from the middle Miocene Choptank Formation, Maryland

Abstract

ABSTRACT A new odontocete genus and species, Macrokentriodon morani, is described from the middle Miocene Choptank Formation of Maryland. This specimen consists of the skull, periotic, and teeth of a single individual. It is placed in the Family Kentriodontidae and the Subfamily Kentriodontinae based on the morphology of the cranial vertex, which is unique to kentriodontines, and features of the periotic. The cranial vertex is flat, roughly pentagonal, formed by nasals and frontals, and is not elevated. The nasals are enlarged and each possesses an oblique groove on the rostral border. Macrokentriodon morani is two to three times larger than other described kentriodontine species, and it possesses relatively larger and fewer teeth. It is similar in size to Hadrodelphis calvertense, but has a cranial vertex distinctly different from that lophocetine kentriodontid. The Kentriodontinae are basal delphinoids of late Oligocene to late Miocene age, and are known from the Atlantic and Pacific ocean basins. This ...