Cabillus atripelvicus, a new species of gobiid fish from the Ogasawara Islands, with a key to species of the genus

Cabillus atripelvicus is described from three specimens, 26.1-40.6 mm in standard length, collected from depth 17-29 m in the Ogasawara Islands. In addition, two small specimens taken by dredge in 50-55 m from Sagami Bay, Honshu, and one from Tachibana Bay, Kyushu, are identified as this species but not designated as paratypes. Cabillus atripelvicus is distinguished from the four other described species of the genus by its high count of 18-20 pectoral rays, presence of median predorsal scales, longer pectoral fins, and distinctive color pattern, including black pelvic fins. The range of C. lacertops Smith, 1959 is extended east to the Marshall Islands and that of C. tongarevae (Fowler, 1927) east to American Samoa. More species remain to be described in the genus.