Protula bispiralis ( Savigny, 1822 )

Sun, Yanan, Ten, Harry A. & Qiu, Jian-Wen, 2012, Serpulidae (Annelida: Polychaeta) from Hong Kong, Zootaxa 3424, pp. 1-42 : 24-25

Protula bispiralis ( Savigny, 1822)

( Figure 3 K–O)

Serpula bispiralis Savigny, 1822: 75 .

Protula magnifica Straughan, 1967: 41 .

Protula bispiralis — Day 1967: 818; ten Hove 1994: 109; Pillai 2009: 99. Spirobranchus sp. not Blainville, 1818, sensu Scott 1984 fig. 22.

Material examined. AM W41409, 1 specimen (22°22’N, 114°17’E, Sharp Island, in crevice of rocks, 6 m, May 21, 2009).

Description. TUBE: white, circular in cross-section, rugose outside. Collar-like rings and medial keel absent. Up to 10 mm wide, lumen diameter 0.8 mm.

BRANCHIAE: branchial crown consisting of up to 80 radioles on each side, arranged in spiral with three whorls. Radioles with short pinnules and filiform tips; joined for one-third of their length ( Figure 3 K). Branchial eyes absent.

PEDUNCLE: absent.

OPERCULUM: absent.

COLLAR AND THORACIC MEMBRANES: collar trilobed; thoracic membranes well developed, extending past chaetiger 7 in apron across anterior abdominal chaetigers.

THORAX: with 7 chaetigers. Collar chaetae and other thoracic notochaetae limbate capillaries ( Figure 3 L–M), Apomatus -chaetae not observed. Thoracic uncini absent.

ABDOMEN: abdominal neurochaetae faintly sickle-shaped, with finely serrated blade ( Figure 3 N). Abdominal uncini rasp-shaped with 2 to 4 rows of teeth and 22 teeth in profile view and rounded peg ( Figure 3 O).

SIZE: length up to 79 mm, width of thorax 8.5 mm.

COLOUR: living worm with a pinkish branchial crown, colour in formalin pale yellow.

Habitat. Depth: 6 m. In coral sand or rock-crevices.

Distribution. Widely distributed in the Indo-West Pacific.

Remarks. The present specimen agrees with the description of Day (1967) except that uncini are missing in all thoracic chaetigers, rather than in just the first three. Protula bispiralis is considered to be a species complex (ten Hove & Kupriyanova 2009). Scott (1984: 26, fig. 22) gave a good colour photograph of the branchial crown but erroneously identified the specimen as Spirobranchus sp.

Figures

FIGURE 3. A – B: Hydroides albiceps, AM W 40534, operculum, lateral and apical view. C: Hydroides operculatus, AM W 41406, operculum, lateral view. D – J: Hydroides rhombobulus, AM W 41407. D – E, operculum, lateral and apical view. F, G, collar chaetae. H, thoracic limbate chaeta. I, thoracic uncinus. J, abdominal uncinus. K – O: Protula bispiralis, AM W 41409. K, dorsal view; L, limbate collar chaeta. M, limbate chaeta from chaetiger 6. N, abdominal sickle-shaped chaeta. O; abdominal uncinus. P – Q: Serpula cf. granulosa, AM W 40554, operculum, lateral and apical view. (Scale bars: A – E = 0.2 mm, F – G, O = 50 μm, I – J = 10 μm, K = 5 mm, L – N = 100 μm, P – Q = 1 mm)