Description

SINGLE PAPER

Volume 15, Issue 2 – 15 April 2009

Richard Winterbottom: A new species of the genus Trimma (Percomorpha; Gobiidae) from Helen Reef, South-West Islands of Palau, pp. 109-116

Abstract
A new species of the genus Trimma is described based on 41 specimens from the southern tip of Helen Reef, SW Islands of Palau. Trimma hotsarihiensis n. sp. is characterized by the absence of scales in the predorsal midline, no cheek or opercular scales, a broad U-shaped interorbital trough and a slit-like postorbital trench, a fleshy ridge, the dermal crest, in the dorsal midline extending from the first spine of the dorsal fin and decreasing in height anteriorly, reaching to a vertical above the vertical limb of the preopercle, no elongate dorsal spines, usually 9 dorsal-fin rays, 17 pectoral-fin rays with 6-12 of the inner rays branched, and an unbranched fifth pelvic-fin ray. When freshly collected, T. hotsarihiensis is yellow with small yellow spots on the caudal fin, a black basal stripe in the dorsal and anal fins bordered distally by an approximately equalwidth yellow stripe in the dorsal fins and rest of anal fin yellow, a short, diffuse, irregular dark stripe extending posteriorly from immediately above the opercle, and a dark, pupilwidth, internal band extending along the midline from the occipital region, tapering out at the end of the caudal peduncle. Preserved specimens are straw-yellow, with the dark external stripes in the dorsal and anal fins and above the opercle, and, usually, the dark internal bar, still visible. Trimma hotsarihiensis is currently known only from Helen Reef just north of the equator in the western Pacific Ocean.