A new species of Eustomias (Nominostomias) (Stomiiformes: Stomiidae) from the Kermadec Ridge-Tonga Trench region, western South Pacific Ocean, with notes on the barbel morphology of E. trewavasae

Abstract

A new species of dragonfish Eustomias (Nominostomias) robertsi is described from the western South Pacific Ocean. The new species, the first record of a member of Eustomias (Nominostomias) Group III (sensu Gibbs et al. 1983) from the region, it is most similar to Eustomias suluensis in barbel morphology. However, it has a smaller proximal and distal bulb distance, the smallest distal inter-bulb value in the group, and much longer terminal filaments. Comments are also provided on the morphology of the diagnostic features on the barbel of Eustomias trewavasae, including an important character overlooked in the original description of the species. The barbel morphology is redescribed taking this into account. A brief observation is made recording the first record of the subgenus Triclonostomias from the western South Pacific Ocean.