Hexelasma velutinum Hoek, 1913

Chan, Benny K. K., Prabowo, Romanus Edy & Lee, Kwen-Shen, 2010, North West Pacific deep-sea barnacles (Cirripedia, Thoracica) collected by the TAIWAN expeditions, with descriptions of two new species, Zootaxa 2405, pp. 1-47 : 41

Hexelasma velutinum Hoek, 1913

Figures 2 I, 29, 30

Hexelasma velutinum Hoek, 1913: 246 , pl. 26 figs 1–6. — Broch, 1931: 53. — Hiro, 1933: 70, pl. 3 fig. 2. — Utinomi, 1968: 30. — Newman & Ross, 1971:155. — Newman & Ross, 1976: 46. — Jones, 2000: 273, fig. 64, tabs 28–31. — Liu & Ren, 2007: 328, fig. 146.

Material examined. CEL-BB-102, 1 specimen, Stn. CP371 (24º28.521’N, 122º12.821’E, 26 Aug. 2006, depth: 582–613 m), BD 13.88 mm.

Diagnosis. Shell with 6 compartmental plates; carina, carinolateral and lateral plates with alae, radii absent; rostrum with radii and alae absent; parietes solid, longitudinal ribs on inner surface absent; basis membranous; intermediate segments of cirri IV–VI bearing 2 pairs of long setae.

Description. Shell white, conical or cylindrical, operculum large; shell surface with parallel growth lines, covered by membrane with fine, short setae ( Fig. 2 I); 6 compartmental plates; carina, carinolateral and lateral plates with alae, radii absent; rostrum with radii and alae absent ( Fig. 2 I); parietes solid, longitudinal ribs on inner surface absent; basis membranous; scutum triangular, occludent margin straight, with large teeth, tergal margin straight; tergum narrow, scutal margin long, straight, basiscutal angle oblique, spur pronounced. Maxilla subtriangular ( Fig. 29 A), inferior and superior margins setose; maxillule with cutting edge notched, 2 long, cuspidate setae above notch, 3 fine short setae in notch, 12 fine setae below notch ( Fig. 29 B); mandible with 4 teeth, first separated from remainder ( Figs 29 C, G), lower margin smooth ( Fig. 29 E), inferior angle sharp ( Fig. 29 E); mandibular palp rectangular, apex blunt, dense setae on superior margin and distally ( Fig. 29 D); labrum concave, deep notch absent, cutting edge with fine bidentate and tridentate teeth ( Fig. 29 H). Cirrus I with rami unequal, outer ramus shorter, 11 segmented, inner ramus longer 11-segmented ( Fig. 30 A); cirrus II with rami subequal, outer ramus 14-segmented, inner ramus 13-segmented ( Fig. 30 B); cirrus III with rami subequal, outer ramus 37-segmented, inner ramus 43-segmented ( Fig. 30 C); intermediate segments of cirri IV–VI with 2 pairs of long setae ( Fig. 30 D).

Distribution. South China Sea, Japan, Taiwan and the Philippines.

Remarks. This is a new record for Taiwanese waters.

Figures

FIGURE 2. Taiwanese deep-sea barnacles (right side view on A – C, top view for D – I). A. Annandaleum japonicum biramosum, B. Litoscalpellum spinosus sp. nov., C. Scalpellum stearnsii, D. Altiverruca longimandible sp. nov., E. Altiverruca navicula, F. Metaverruca defayeae, G. Metaverruca recta, H. Rostratoverruca krugeri, I. Hexelasma velutinum.

FIGURE 29. Hexelasma velutinum. A. Maxilla, B. Maxillule, C. Mandible, D. Mandibular palp, E. Lower margin of mandible, F. Labrum, G. First teeth of mandible, H. Cutting edge of mandible, showing fine teeth. Scale bars in µm.

FIGURE 30. Hexelasma velutinum. A. Cirrus I, B. Cirrus II, C. Cirrus III, D. intermediate segments of inner ramus of cirrus VI.