A new pygmy goby of genus Trimmatom (Teleostei: Gobiidae) from Lanyu Island, Taiwan.

The new pygmy goby of genus Trimmatom was found and collected from Lanyu Island off Taiwan via SCUBA diving. The new species, T. lanyuensis, can be well distinguished from other congeneric species by the unique combination of the following features: (1) fin rays: second dorsal fin rays 10, anal fin rays 10, pectoral fin rays 21; (2) squamation: longitudinal scale rows 27-28 (modally 27), predorsal naked; and (3) specific coloration: head and body with greyish brown background bearing bloody red marks. Lateral body with pale gray 5 vertical bars, anterior 4 longer extension to ventral side, the last one shorter passing less than only half way of lateral side against the red body. Head generally with entirely gray in cheek. Opercle with two red vertical lines. The two red lines interrupted to dorsal two cross red bars. Caudal fin pinkish red, with basal region bloody red. Pectoral fin bloody red with basal central red mark. A brief comparison of related congeneric species will also be addressed.