Thirty-five individuals of six priacanthid fish species were sampled from different localities along the coast of India covering the Arabian Sea and Bay of Bengal. The partial sequence of 16S rRNA and cytochrome oxidase subunit I (COI) genes were analyzed for species identification and phylogenetic relationship among the Indian priacanthids (Priacanthus hamrur, P. prolixus, P. blochii, P. sagittarius, Cookeolus japonicus, and Pristigenys refulgens). The intraspecies genetic distance ranged from 0.000 to 0.002, while distances varied from 0.008 to 0.157 interspecies based on 16S sequences. Using COI data analysis, the intraspecies genetic distance ranged from 0.000 to 0.005, while interspecies distances varied from 0.009 to 0.108. Several sequences labeled Priacanthus hamrur in GenBank are shown to be P. prolixus. We also observed cryptic speciation in Heteropriacanthus cruentatus. Partial sequences of 16S rRNA and COI genes provided phylogenetic information to distinguish thirteen species of priacanthids, indicating the usefulness of molecular markers in species identification.

Gymnothorax aurocephalus sp. nov. is described herein based on 4 specimens. Three were collected from off Swaraj Dweep Island of Andaman and Nicobar Islands (A&N Islands) from a depth of 125–130 m and one specimen off Interview Island, A&N Islands at a depth of 90 m. This new species is distinguishable from its congeners by the following combination of characters: chocolate brown color overlain with small irregular white spots, golden skin shadings close to rictus; anus slightly before midbody; pointed and serrated jaw teeth; uniserial teeth in jaws and vomer; vertebral formula 7/61/148–149. The species is compared to all its congeners with white spots.