Thryssa mystax (Bloch & Schneider, 1801)

Zainal Abidin, Danial Hariz, Lavoué, Sébastien, Mohd Abu Hassan Alshari, Norli Fauzani, Mohd. Nor, Siti Azizah, A. Rahim, Masazurah & Mohammed Akib, Noor Adelyna, 2021, Ichthyofauna of Sungai Merbok Mangrove Forest Reserve, northwest Peninsular Malaysia, and its adjacent marine waters, Check List 17 (2), pp. 601-631 : 615

Thryssa mystax (Bloch & Schneider, 1801)

Material examined. MALAYSIA • 1, 120 mm TL; Kedah State, Kuala Kedah, Kuala Muda Whispering Market ; 05.578°N, 100.341°E; 6 Dec. 2018; Danial H. Zainal Abidin, Norli F.M.A.H. Alshari leg.; USMFC (82) 00051 . • 1, 141 mm TL; Kedah State, Merbok, Pompang Sungai Merbok ; 05.664°N, 100.381°E; 6 Dec. 2018; Danial H. Zainal Abidin, Norli F.M.A.H. Alshari leg.; USMFC (82) 00052 .

Identification. A moderate-sized species of anchovy (maximum TL about 150 mm); body elongated, compressed and keeled from isthmus to anus; large mouth, its corner behind the eye; anal fin long with three un- branched and 29–37 branched fin rays; lower gill rak- ers 14–16 (on first gill arch); maxilla long, its posterior tip of the maxilla almost reaching to base of first pec- toral fin ray; prepelvic scutes 17–19; post-pelvic scutes 8–13; body uniformly silvery with a conspicuous blackish blotch behind upper part of gill opening; no silver longitudinal stripe; no pigment line on dorsum ( Whitehead et al. 1988).

Thryssa mystax can be easily distinguished from other species of the genus Thryssa occurring in the Merbok river estuary by its long maxilla reaching to base of first pectoral fin ray. Thryssa mystax is a predominantly coastal marine species occasionally caught in brackish ecosystems of this region; it is an economically important species. Otherwise, widely distributed in the Indo- West Pacific region ( Whitehead et al. 1988).