Spirobranchus cf. gaymardi (de Quatrefages, 1866 )

Bastida-Zavala, J. Rolando, 2008, Serpulids (Annelida: Polychaeta) from the Eastern Pacific, including a brief mention of Hawaiian serpulids, Zootaxa 1722, pp. 1-61 : 48

Spirobranchus cf. gaymardi (de Quatrefages, 1866)

( Figures 12A–B)

Cymospira Gaymardi de Quatrefages, 1866: 539–540 , pl. 20, fig. 13. Type locality: Unknown.

Spirobranchus gaymardi .— Fiege and ten Hove, 1999: 356–362, figs. 1–3 (redescription).

Material examined. Seven specimens: Baja California ( Mexico), ECOSUR s.n., UMAR-Poly 97, 5 spec. (approx. 31º53–54’N, 116º41–43’W, Villas las Rosas , near Sauzal, low tide, rock plain, seagrass Phylospadix, molluscs, 1 m, March 6, 2004, coll. SISV, NEV, MATH & PSS) . Colima ( Mexico), UANL 350 (approx. 19º03–06’N, 104º18–22'W, Manzanillo , Oct. 7, 1981, coll. S. Salcedo Martínez, as S. giganteus ) . Oaxaca ( Mexico), UMAR-Poly 98 (15º51’N, 97º04’W, Puerto Escondido , on Spondylus calcifer, VD , 6–10 m, July 4, 2004, coll. SS) .

Diagnosis. Tube white to greyish, with prominent longitudinal ridge. Anteriormost section of tube forms robust spine extending over tube mouth, usually this spine and opening of tube violet, pinkish or bluish in colour; lacking peristomes or alveoli. Opercular peduncle with wide wings. Operculum calcareous, pinkish, circular or pear-shaped, bearing three wide spines emerging from short common stem; two dorso-lateral spines with 2–3 secondary spinules, and one small, broad basal branch; medio-ventral spine bifurcate ( Figs 12A–B). Radioles arranged in spire of up to four whorls. Thoracic membrane extends to last thoracic chaetiger, forming short ventral apron. Collar with “ Spirobranchus ” chaetae, coarsely serrated in sub-apical section.

Measurements. TL= 70 mm (n=2, r:21–70, µ=45.5 ±34.6), THL= 7 mm (n=2, r:4–7, µ=5.5 ±2.1), THW= 10 mm (n=2, r:4–10, µ=7 ±4.2), POL= 17 mm (n=2, r:8.2–17, µ=12.6 ±6.2), OL= 9 mm (n=2, r:3.5–9, µ=6.3 ±3.9), OW= 7 mm (n=2, r:3–7, µ=5 ±2.8), SL= 6 mm (n=2, r:3–6, µ=4.5 ±2.1).

Habitat. Depth: 1–10 m. On spiny oyster Spondylus calcifer ; on rocks with seagrass Phylospadix.

Distribution. The nominal species is distributed in the Indo-Pacific: Japan, South China Sea, Philippines, Indonesia, India, New Caledonia and Australia ( Fiege & ten Hove 1999).

Taxonomic remarks. The specimens revised here are more similar to S. gaymardi (cf. Fiege & ten Hove 1999) than to S. incrassatus or S. spinosus , as the spines of S. cf. gaymardi are emerging from a short common stem. Also, S. cf. gaymardi differs from S. incrassatus as the main spines of the first species are widely divergent ( Fig. 12A), while in S. incrassatus the spines converge ( Fig. 12C). The measurements of the specimens (primarily the larger ones) fall in the range recorded by Fiege and ten Hove (1999). Spirobranchus cf. gaymardi is slightly different from the nominal species, because the middle-ventral spine in S. gaymardi is more variable, "it may be completely absent ... or present only as slight protuberance ... but it may also be several millimetres in length and bifurcate at its tip" (cf. Fiege & ten Hove 1999: 359, Figs 3A–G).