Pelagic fishes of the genus Eustomias (Melanostomiidae) presently associated with Eustomias achirus Parin and Pokhilskaya with the description of five new species

Eustomias achirus, previously known only from the holotype and a few specimens of questionable identity, is unique in that it lacks pectoral-fin rays but has a short, pigmented barbel with three prominent branches similar to the barbels of species with two pectoral-fin rays in the subgenus Dinematochirus. Examination of over 70 previously unreported specimens without pectoral-fin rays and with structurally similar barbels revealed many different forms occurring in all three major oceans. Five of these are described as new species: E. aequatorialis, E. intermedius, and E. insularum from the Atlantic and E. tomentosis and E. woollardi from the Pacific. Several other Indo-Pacific specimens of uncertain status are also reported. All species and forms of the group are distinguished from other members of Dinematochirus by a unique combination of barbel characters.