Descriptions of two new gobies (Gobiidae: Acentrogobius) from Milne Bay Province, Papua New Guinea

Two new species belonging to the gobiid genus Acentrogobius are described from mud-bottom habitat in the vicinity of Alotau, Milne Bay Province, Papua New Guinea. Acentrogobius vanderloosi is described on the basis of three specimens, 30.4–47.7 mm SL. Diagnostic features include the combination of 10 soft dorsal and anal-fin rays, first two dorsal spines with elongate filaments, pectoral-fin rays 20, scales covering the entire cheek and upper portion of the opercle, and a unique colour pattern that includes a pair of yellow cheek stripes, numerous orange spots on the body, and a mid-lateral row of five, horizontally-elongate dark brown blotches, which are not enclosed within parallel dark stripes. Acentrogobius violarisi is described from three specimens, 14.9–30.1 mm SL. It differs from congeners on the basis of its combination of 11 soft dorsal and anal-fin rays, filamentous first dorsal spine, 12–13 predorsal scales, and a colour pattern that includes a mid-lateral row of four, short narrow black bars and spot (at caudal-fin base) enclosed within a pair of brown stripes extending from the pectoral fin to the caudal-fin base, a pair of neon blue cheek stripes, alternating blue and brown bands on the dorsal fins, and orange spots on the upper half of the caudal fin. Both new species were collected/observed at depths from 15–18 m, which is well below the normal depth zone for most members of the genus.