Euscalpellum rostratum (Darwin, 1851)

Figures 1 B, 4

Scalpellum rostratum Darwin, 1851: 259, pl. 6 fig. 7.

Scalpellum (Euscalpellum) rostratum . — Hoek, 1907: 65, pl. 5 fig. 13. — Stubbings, 1936: 19 fig. 7.

Euscalpellum rostratum . — Pilsbry, 1908: 107, figs 1e–f. — Utinomi, 1968: 162, fig. 1. — Zevina, 1978: 1001. — Liu & Ren, 1985: 190, fig. 5, pl. 3 figs 1–2. — Liu & Ren, 2007: 214, fig. 90.

Scalpellum (Smilium) rostratum . — Annandale, 1914: 274.

Smilium rostratum . — Broch, 1931: 14. — Nilsson-Cantell, 1938: 24, fig. 1.

Material examined. ASIZCR000225, 1 specimen, Stn. CP164 (22°15.57’N, 120°35.56’E, 25 May 2002, depth: 60–90 m), CL 9.76 mm, CW 6.44 mm, PL 7.6 mm.

Diagnosis. Capitulum higher than wide; 15 white plates; subcarina present; rostrum large, well developed; inframedian latus diamond-shaped; rostrolatus quadrangular, umbo apical.

Description. Capitulum higher than wide, 15 fully calcified, white plates; tergum truncated, quadrangular, wider than high, occludent and basal margins slightly convex, umbo apical (Fig. 1 B); scutum irregularlyshaped, occludent margin almost straight, tergal, lateral and basal margins convex, umbo subapical; upper latus pentagonal, tergal margin longest, apex produced over scutal tergal angle, umbo apical (Fig. 1 B); inframedian latus diamond-shaped, umbo apical (Fig. 1 B); rostrolatus quadrangular, umbo apical; carinolatus quadrangular, umbo apical (Fig. 1 B); rostrum well developed, large, diamond-shaped; carina strongly bowed, umbo apical, roof wide, laterally convex; subcarina quadrangular (Fig. 1 B). Peduncle long, with dense, fine scales (Fig. 1 B). Maxilla bilobed, setae distributed into 2 main clusters (Fig. 4 A); maxillule cutting edge with small notch close to apical region, cutting edge not straight, basal region below notch slightly extended; 2 long setae above notch,> 6 setae below notch,> 10 large setae along extended basal region (Fig. 4 B); mandible with 6 teeth, first separated from remainder, inferior angle ending in single sharp seta (Fig. 4 C); mandibular palp elongated, setae on superior and inferior margins and distally (Fig. 4 D); labrum with cutting edge concave, smooth, teeth absent. Cirrus I separated from remaining cirri, rami unequal, outer ramus longer, 12-segmented, inner ramus shorter, 8-segmented (Fig. 4 F); cirri II–VI with rami sub-equal; cirrus II with outer ramus 16-segmented, inner ramus 14-segmented (Fig. 4 G); caudal appendage short, 1-segmented, apex with dense, short setae, appendage length <height of basal segment of pedicle of cirrus VI (Fig. 4 E).

Distribution. South China Sea, Taiwan, the Philippines, Malay Archipelago, Arabian Sea. Remarks. This is a new record for Taiwanese waters.