Mystus alasensis Ng & Hadiaty 2005

Distinguished from all other Southeast Asian congeners, except Mystus castaneus, M. impluviatus and M. nigriceps by the following combination of characters: a moderately long (29-37% SL), low adipose-fin, uniform body color, fossa on midline of the cranium not reaching to the base of the supraoccipital process and extremely long maxillary barbels that reach beyond the base of the caudal fin (Ref. 55439). Differs from M. castaneus, M. impluviatus and M. nigriceps in lacking a dark triangular mark at the base of the caudal fin. Further differs from M. nigriceps in having a longer (34.3-36.3% SL vs. 26.3-31.4), deeper (6.7-7.5% SL vs. 4.1-6.0) adipose fin and longer pelvic fins (17.6-20.2% SL vs. 13.4-16.7); and from M. castaenus and M. impluviatus in having a more gently-sloping dorsal profile of the head. Differs also from M. impluviatus in lacking (vs. presence) of fontanel on the supraoccipital and having a deeper adipose fin (6.7-7.5% SL vs. 4.7-6.0) (Ref. 55439).

Dorsal spines (total): 1; Dorsal soft rays (total): 7; Analsoft rays: 12 - 14; Vertebrae: 38 - 41

Oviparous, distinct pairing possibly like other members of the same family (Ref. 205).