Cavern Triplefin

Description: Dorsal rays III +XIII- XIV + 10-11, 1-2 free pterygiophores; anal fin I, 20; pectoral rays 16-17 (usually 1+9+7); pelvic fin I,2; caudal rays 13, branched 9, procurrent 9 each in both dorsal and ventral. Vertebrae 11+ 26; last pleural and epipleural ribs on 11th vertebral centrum. Lateral line continuous, pored scales 21-27 (usually 25); scales ctenoid; largest (twice in size) at the area posterior to pectoral-fin base and below the lateral line; head, nape, belly, and pectoral-fin base scaleless. Mandibular sensory pores 5-12 + 5-10 + 5-12 (usually 9+5+8); orbital cirri minute (Ref. 52308, 90102). Male overall dusky, head darker ventrally, body with 7-8 bars, irregular and faint; female tan to dusky brown with bars more faint (Ref. 90102).

Dorsal spines (total): 16 - 17; Dorsal soft rays (total): 10 - 11; Analspines: 1; Analsoft rays: 20; Vertebrae: 37

Inhabits sand channels in patch reefs (Ref. 90102). Found on large boulders of Porites and scattered small corals (Ref. 52308).

Adults inhabit sand channels in patch reefs (Ref. 90102). Eggs are hemispherical and covered with numerous sticky threads that anchor them in the algae on the nesting sites (Ref. 240). Larvae are planktonic which occur primarily in shallow, nearshore waters (Ref. 94114).

Helcogramma lacuna, the cavern triplefin, is a species of triplefin blenny in the genus Helcogramma. It was described by Jeffrey T. Williams and Jeffery C. Howe in 2003. This species has only been recorded in the Similan Islands in the Andaman Sea, part of Thailand.