First Records of the Vanishing Silhouette Goby Silhouettea evanida (Pisces: Actinopterygii: Gobiidae) from the South China Sea, with Notes on Reproductive Behavior of the Species

Five sand goby specimens (four males and one female), collected from runnels on the sandy coast of Kuantan, east coast of Peninsular Malaysia were identified as Silhouettea evanida Larson and Miller, 1986, characterized by the following combination of characters: dorsal-fin rays VI-I, 10; anal-fin rays I, 12; pectoral-fin rays 14–16; lateral scale rows 24 or 25; nape with single narrow, densely pigmented transverse band; and a single black blotch posteriorly on first dorsal fin. Apparent breeding colors in larger male specimens included more dense pigmentation on the branchiostegal membrane, pelvic fin and anal fin, compared with female and the smallest male. The molecular analysis of partial COI gene supported that the difference of dark males and the smallest pale male is intraspecific. The field survey revealed that S. evanida spawns eggs on the under surface of embedded shell fragments, after constructing radial grooves directed to the spawning bed, not unlike the spawning behavior of Favonigobius gymnauchen (Bleeker, 1860), which occupies a similar sandy habitat. The specimens represent the first record of S. evanida from the South China Sea.