Based on new material collected from the Upper Devonian, “Catskill Formation” of Pennsylvania, and a comparison with variation in Bothriolepis canadensis and B. yeungae, it is suggested that the species Bothriolepis minor, B. virginiensis, B. coloradensis, and B. darbiensis, pending the discovery of more complete materials, cannot reliably be distinguished from Bothriolepis nitida (Leidy, 1856). Although some of the present named species may be invalid, Bothriolepis as a whole (some 70 species world-wide, over 20 million years) is not abnormally speciose when compared with modern bottom-living species. A better understanding of the species of Bothriolepis is essential if the potential of this genus for palaeobiogeography is to be realized.