New records of congrid eels of the genus Bathycongrus (Congridae) in the west-central tropical part of the Pacific Ocean, with a description of three new species

Abstract

Results of the study of a collection of bathyal benthopelagic congrid eels of the genus Bathycongrus collected during the MUSORSTOM and other expeditions in the west-central tropical part of the Pacific Ocean are presented. The synonymy and brief descriptions of three known species (B. guttulatus, B. odontostomus, and B. wallacei) and more detailed descriptions of three new species (B. longicavis, B. parapolyporus, and B. unimaculatus) are provided. The first species, B. longicavis, is described from one specimen caught in the New Hebrides Trench at a depth of approximately 600 m; it differs from all related species of the genus in its maximum number of trunk vertebrae (68), relatively short head (35% aA), and long mouth cleft (45% c). B. parapolyporus, whose type specimens were caught off the Fiji Islands and in the South China Sea at depths of 310–500 m, differs from all the known Indo-Pacific species of the genus in its greater number of head pores in the supraorbital (5–6), infraorbital (7–8), and preoperculo-mandibular (11) canals, and from the West-Atlantic B. polyporus, which is similar to it in the number of head pores, in its smaller number of vertebrae (150–160) and preanal pores (31–33). The third species, B. unimaculatus, described from one specimen caught in the Loyalty Basin at a depth of 470–480 m, differs from the other two West-Pacific species of this group (B. bleekeri and B. trimaculatus) in its greater number of vertebrae (137) and the presence of a dark wide band along the posterior part of the anal fin. The geographic distribution is considered, and the habitat depths of the genus species under consideration are listed.