Litoscalpellum spinosus sp. nov.

Figures 2 B, 16, 17

Material examined. Holotype: NMNS 6058-001, 1 specimen, Stn. CP238 (25º12.28’N, 123º1.85’E, 23 Jul. 2004, depth: 1650–1689 m), CL 27.75 mm, CW 17.54 mm, PL 11.85 mm.

Diagnosis. Capitulum with 14 partially calcified plates; plates white, surfaces covered by dense, short setae; inframedial latus not touching upper latus; somatic body with dorsal thoracic, sharp processes, located at bases of cirri III and IV.

Description. Capitulum with 14 partially calcified plates, plates white, surfaces covered by dense, short setae, separated by chitinous interspaces (Figs 2 B, 17A); tergum triangular, umbo apical, apex slightly truncated, scutal, occludent and carinal margins straight (Figs 2 B, 17A); scutum quadrangular, higher than wide, apex produced at tergal margin, slightly overlaying tergum, umbo apical, occludent margin slightly convex, lateral, basal and tergal margins straight (Figs 2 B, 17A); upper latus quadrangular, carinal margin shortest, tergal and lateral margins convex, scutal margin slightly concave; rostrum very narrow, small (Figs 2 B, 17A); inframedian latus triangular, wider than high, not touching upper latus, umbo apical; rostrolatus quadrangular, occludent and scutal margins forming right angle, scutal margin longest; carinolatus subtriangular, lateral margin convex, umbo at basicarinal angle, angle not extending beyond carina; carina bowed, roof flat, umbo apical (Figs 2 B, 17A). Peduncle with white, concentric scales (Fig. 2 B). Maxilla quadrangular, setae divided into 3 clusters (Fig. 16 A); cutting edge of maxillule short, notched, 3 large, long cuspidate setae and 2 short, cuspidate seta above notch, several large cuspidate setae below notch (Fig. 16 B); mandible with 3 teeth, first widely separated from second and third, lower margin smooth, inferior angle sharp with dense setae (Figs 16 C, E, G); mandibular palp elongated, narrow, setae distally and along superior margin, inferior margin naked (Fig. 16 D); labrum strongly concave, cutting edge with fine, sharp teeth (Figs 16 F, H). Cirrus I separated from cirri II–VI, rami subequal, outer ramus slender, longer, 13-segmented, inner ramus broader, shorter, 8-segmented (Fig. 17 C); cirri II–VI with rami subequal; cirrus II with outer ramus 19- segmented, inner ramus 30-segmented (Fig. 17 E); cirrus III with outer ramus 18-segmented; inner ramus 21- segmented; cirrus IV with outer ramus 25-segmented, inner ramus 7-segmented; cirrus V with outer ramus 25-segmented, inner ramus 25-segmented; cirrus VI with outer ramus 29-segmented, inner ramus 32- segmented; caudal appendage very short, 1-segmented, length <height of basal segment of cirrus VI (Figs 17 B, D); somatic body with dorsal thoracic, sharp processes, located at bases of cirri III and IV (Fig. 17 B).

Etymology. The name spinosus is to denote the dorsal thoracic, sharp processes, located at the bases of cirri III and IV, a diagnostic character of this species.

Distribution. Presently known only from the type locality.

Remarks. The capitular morphology of Litoscalpellum spinosus sp. nov. is similar to L. affbricatum Foster, 1978 . However, the capitulum of L. affbricatum is covered by a naked, smooth integument (Foster, 1978) whilst that of L. spinosus sp. nov. is covered by dense, short hairs. The rostrum of L. affbricatum is large, wide and triangular (Fig. 17 G; Foster, 1978), whilst the rostrum of L. spinosus sp. nov. is narrow (Fig. 17 F). The somatic body of L. affbricatum is not reported to have dorsal thoracic, sharp processes at the bases of cirri III and IV. Previously, no Litoscalpellum species has been reported to possess dorsal thoracic, sharp processes.