Abstract
Belone is distinguished from other genera of Belonidae mostly because of its complete cephalic sensory system, presence of gill rakers, vomerine teeth, and the pattern of its dentition. This eastern North Atlantic genus contains two extant species and at least three described fossil species from Lower Oligocene and Upper Miocene formations in Europe. †Belone countermani, sp. nov., a new species of needlefish from the Tortonian Upper Miocene St. Marys Formation of Calvert Cliffs (Maryland, U.S.A.), is described herein based on a well-preserved three-dimensional associated pair of upper and lower jaws. This rostrum represents the only record of this genus in the western North Atlantic Ocean. †Belone countermani is characterized by a unique dental pattern on the dentary. The dentary commissural region is filled with several rows of small accessory teeth (five to seven) that gradually decrease in number of rows; along the symphysial region there is one inner row of conical teeth and one external row of accessory teeth. Discovery of †Belone countermani indicates that extant Belone species are a relict diversity of an old group that had a wider distribution that included the western North Atlantic.