Scabrilucina victorialis (Melvill 1899)

Shell white, thin, often semi-translucent, H to 43 mm, L to 39 mm, higher than long, H/L = 1.03±SD 0.03 (n=17), moderately inflated T/L 0.27±SD 0.014 (n=17), outline subtrigonal in larger shells, juvenile shells subcircular. Posterior sulcus, prominent, deeply incised, with marginal sinus; anterior sulcus narrow and shallow. Sculpture of fine, closely spaced (200–500 µm apart), thin, sharp-edged, striated, commarginal lamellae (Figs 2A–C) that narrow to around 30 µm at the distal edges and are slightly elevated along the posterior and anterior dorsal margins. Fine sediment is frequently trapped between lamellae. Protoconch (Fig. 2D): PI 150 mm, PI + PII 165 µm, PII with 2-3 growth increments. Lunule long, lanceolate and asymmetric, slightly larger in left valve. Ligament short, set in narrow groove. Hinge plate narrow, LV with 2 cardinal teeth, the anteriormost reduced and often obscured by ventral extension of lunule (Fig. 1M–P), lateral teeth absent; RV with 1-2 small cardinal teeth, sometimes obscure, small anterior lateral tooth sometimes visible in younger shells (Fig. 1P). Anterior adductor muscle scar long, thin, tapering at ventral tip, detached for ½–⅔ length and diverging ventrally at angle of 25–30° from pallial line, posterior adductor scar ovate. Pallial line broad, continuous, inner shell surface rough with many small translucent circular spots representing mantle attachment points and prominent radial grooves. Track of pallial blood vessel visible. Inner shell margin smooth.

50 – ca 150 m in offshore muds, northern Arabian Sea, Gulf of Oman, northeastern Arabian Gulf (Fig. 4). Smith (1906) records victorialis from the Arabian Gulf, 47 fthms, Investigator station 346, 26°37'30"N, 53°03'30"E.