A preliminary review of the Indo-Pacific gobiid fishes of the genus Gnatholepis.

The gobiid fish genus Gnatholepis Bleeker is characterised as follows: dorsal-fin rays VI+I,1012, the spines slender, none filamentous; anal-fin rays I,1112; pectoral-fin rays 14-19, none free of membrane; pelvic disc with a frenum; scales on body largely ctenoid, 28-31 in longitudinal series; gill-rakers short, 1 + 3-4; anterior interorbital pores 2; sensory papillae on cheek primarily in a pattern of 4 or 5 vertical rows; body moderately elongate, the depth 3.8-5.4 in SL; head and body compressed; dorsal profile of head initially near-vertical, often with a slight anterior protuberance above upper lip; lower lip with a ventral flap on side of jaw; mouth inferior, the gape slightly oblique; teeth anteriorly in jaws in several rows, the outer row in upper jaw as slender well spaced canines (outer row of teeth at front of lower jaw may or may not be caniniform); tongue bilobed; gill opening ending slightly below level of lower edge of pectoral-fin base; caudal fin rounded, usually longer than head; a dark line extending ventrally from eye, sometimes with one or more side branches. Of the 21 nominal Indo-Pacific species that have been described in Gnatholepis, only 5 are recognised as valid. G. anjerensis (Bleeker), for which a neotype is described, occurs from East Africa and the Red Sea to the Hawaiian Islands and French Polynesia [synonyms include G. deltoides (Seale), G. knighti Jordan and Evermann, and G. corlettei Herre]. G. cauerensis (Bleeker) is provisionally divided into 4 subspecies, mainly by modal differences in pectoral-ray counts and slight colour variation: G.cauerensis cauerensis from East Africa to the Society Islands (G. scapulostigma Herre and G. inconsequens Whitley are synonyms); G. c. australis from Rarotonga, Cook Islands to the Pitcairn Islands; G. c. hawaiiensis from the Hawaiian Islands; and G. c. pascuensis from Easter Island. G. davaoensis Seale, also provided with a neotype and description, ranges from the Ryukyu Islands to the Solomon Islands, Papua New Guinea, and Indonesia (G. gemmus Herre is a synonym). G. gymnocara, n. sp., is described from 26 specimens from shallow water of Queensland and the Northern Territory, Australia; it is unique in having 12 anal-fin soft-rays, prepectoral scales, no scales on cheek and opercle, median predorsal zone naked or with only a few small scales across its anterior part, and a large black spot on fourth interspinous membrane of dorsal fin in males. Gnatholepis sp., also a new species from northern Australia, will be described by Helen K. Larson; it is distinct in having 10 dorsal soft-rays, 15-17 pectoral-fin rays (modally 16), no scales on cheek, opercle, median predorsal zone, or prepectoral area; and the last 2 to 4 mid-lateral blotches of the male dark brown to black. The count of pectoral-fin rays is the most useful meristic character to separate the species and subspecies of Gnatholepis: G. anjerensis, with 14-17 rays, has a strongly modal count of 16; G. cauerensis cauerensis and G. c. hawaiiensis have 16-19 rays (strongly modal 17); G. c. australis has 17-19 rays (modally 18); G. c. pascuensis has 18 or 19 rays, modally 19; G. davaoensis has 15-17 rays, modally 17.