Length to 55 mm (Eusirus properdentatus 1). Similar in appearance to Eusirus perdentatus. Pereonites V-VII, pleonites I-III with dorsal spines, urosomite I carinate. Eyes large, pear-like. Lateral lobes of head subrectangular, rounded, slightly produced. ANT I slightly longer than ANT II; accessory flagellum uni-articulate. Peduncle of ANT II reaching three quarters of length of peduncular ART 2 of ANT I. Flagellum of ANT II 3.5 times as long as peduncular ART 4 and 5 combined. Ventral part of ART of ANT I, dorsal part of flagellar ART, 4-5 peduncular ART of ANT II calceolate. Mouth parts as in E. perdentatus but without distal denticles on ART 2 of palp of MXP, inner margin of that ART nearly smooth. P I and II subequal (Eusirus properdentatus 2). ART 4 and 6 in P III-IV subequal, ART 5 shorter. Length of ART 4, 5, and 6 of P V-VII in ratio 1:2:3. Epimeral plate III weakly dentate. Rami of UR III subequal. Telson about 20 % cleft, incised (Eusirus properdentatus 4), top reaching middle of rami of UR III.