Gobiodon howsoni, a new species of coral reef fish (Gobiidae: Teleostei) from Rowley Shoals, Western Australia
by Gerald R. Allen – aqua 27 (1) pp. 23-35
A new species of gobiid fish, Gobiodon howsoni, is described from north-western Australia on the basis of 15 specimens, 15.8-27.1 mm SL. It is separable from congenerics on the basis of its unique live colour pattern: semitranslucent greyish with a bifurcate white stripe straddling the spinal column, a narrow brown stripe on the back extending from the side of the nape to the caudal peduncle, and a wider brown stripe on the ventral portion of the body extending from the pectoral-fin axil to the caudal peduncle. Some smaller individuals (< about 20 mm SL) possess a strong yellow tint on the head and body, and lack the dorsal-most brown stripe on the side. The new species also differs from most members of the genus in having a relatively low number of pectoral-fin rays (15-17, usually 16). Other features include: dorsal-fin rays VI+I,10, anal-fin rays I,9 (rarely I,8), branched caudal-fin rays usually 15 (occasionally 14, especially specimens < 16 mm SL), anterior dentary with a single enlarged canine posterior to the main band of smaller teeth, and the aperture of the genital papilla reaching or nearly reaching the anal-fin origin when adpressed. The species is most similar to and sympatric with G. okinawae, but differs in usually having 15 versus 13 branched caudal rays, one versus two enlarged canines on the posterior dentary, the genital papilla usually reaching the anal-fin origin versus falling well short of the anal fin, and possessing 1-2 brown stripes on the body versus a uniform bright yellow colour.