Spirobranchus spinosus Moore, 1923

Bastida-Zavala, J. Rolando, 2008, Serpulids (Annelida: Polychaeta) from the Eastern Pacific, including a brief mention of Hawaiian serpulids, Zootaxa 1722, pp. 1-61 : 51

Spirobranchus spinosus Moore, 1923

( Figures 13B–C)

Spirobranchus spinosus Moore, 1923: 248–250 , pl. 18, fig. 47. Type locality: Off Santa Barbara Island , California, USA. Spirobranchus spinosus .— Hartman, 1969: 775–776, figs. 1–5, Southern California, USA .

Material examined. More than 20 specimens: California ( Mexico), USNM 17109, type (approx. 33º22– 24’N, 119º39–44’W, off Santa Barbara, R / V Albatross, sta. 4417, 68 m, April 12, 1904). Baja California ( Mexico), ECOSUR s.n., UMAR-Poly 104, 20+ spec. (approx. 31º53–54’N, 116º41–43’W, Villas las Rosas, near Sauzal, low tide, rock plain with seagrass Phylospadix, molluscs, 1 m, March 6, 2004, coll. SISV, NEV, MATH & PSS) .

Diagnosis. Tube bluish with prominent longitudinal ridge, lacking peristomes or alveoli. Opercular peduncle with wide wings. Operculum calcareous, circular or pear-shaped; plate with five short thin spines (one lost, noted by the fracture mark on plate), arising from middle of opercular plate, with 5–8 spinules on each ( Figs 13B–C). Radioles arranged in spire with up to four whorls. Thoracic membrane extends to last thoracic chaetiger, forming short ventral apron. Collar with “ Spirobranchus ” chaetae coarsely serrated in subapical section.

Measurements. TL=20.5 mm, THL=3.8 mm, THW=2.2 mm, POL=6.7 mm, OL=2.3 mm, OW=2.2 mm, SL=1.5 mm.

Habitat. Depth: 1–68 m. On rocks with seagrass Phylospadix.

Distribution. Temperate Eastern Pacific. California ( USA) to Baja California ( Mexico) ( Hartman 1969).

Taxonomic remarks. Spirobranchus spinosus was considered a part of the S. giganteus complex (cf. ten Hove 1970), but elevated to full species by Fiege and ten Hove (1999: 363). The specimens revised here, with five to seven spines ( Figs 13B–C), is different from the other Spirobranchus species recorded from the Eastern Pacific ( S. cf. gaymardi , S. incrassatus ) and more similar to S. dendropoma (Gulf of Mexico) or S. tetraceros (Indo-Pacific) (cf. ten Hove 1970; Bastida-Zavala & Salazar-Vallejo 2001). The measurements also indicate that this is a smaller species of Spirobranchus , from different ecological conditions (temperate waters).

Remarks. Gotshall (1994: 42) recorded to S. spinosus with pinkish tubes.