Key to species of genus Archocentrus
14a(7a) Teeth tricuspid (except symphysial, sometimes truncate) ........................ Archocentrus multispinosus
14b All teeth pointed ................................................................................................................................ 15
15a(14b) Two opercular spots (Fig. 2); D. XVI; A. IX -XI ........................................ Archocentrus centrarchus
15b One opercular spot (part of longitudinal stripe) (Fig. 4); D. XVIII -XIX; A. XI -XII ........................... .............................................................................................................. …. Archocentrus spinosissimus