Pyrgopolon ctenactis ( Mörch, 1863 )

Bastida-Zavala, J. Rolando, 2008, Serpulids (Annelida: Polychaeta) from the Eastern Pacific, including a brief mention of Hawaiian serpulids, Zootaxa 1722, pp. 1-61 : 42

Pyrgopolon ctenactis ( Mörch, 1863)

( Figures 10A–D)

Serpula (Sclerostyla) ctenactis Mörch, 1863: 386 . Type locality: St. Thomas , Lesser Antilles.

Sclerostyla ctenactis .— Bush, 1905: 224 (designation).

Sclerostyla ctenactis .— ten Hove, 1973: 6–12, figs. 1–4, 7, 20–31, pls. 1, 3a–b, 3, 7 (revision of the genus).

Pyrgopolon ctenactis .— Jäger, 1993: 95 (designation).

Material examined. Many specimens (30+): Baja California ( Mexico), LACM-AHF s.n., empty tube (28º54’55”N, 118º14’W, 3.8 km north of South Bluff, Isla Guadalupe, Velero IV, sta. 1928, shore, rock, kelp, crevices filled with boulders, Dec. 20, 1949). Baja California Sur ( Mexico), UANL 364, 9 spec. (24º47’N, 112º18’W, Cabo San Lazaro, Bahia Magdalena, April, 1988, coll. JALG); USNM 129207, UMAR-Poly 107, several specimens (26º13’N, 112º32’W, Punta San Juanico, 30 m, April 28, 1988, coll. JALG). Guerrero ( Mexico), SV-pc, 2 spec. (16º50’33”N, 99º54’39”W, Punta Manzanillo, Acapulco, Aug. 4, 1988, coll. SISV); UMAR-Poly 108 (16º50’N, 99º54’W, La Quebrada, Acapulco, on Muricanthus and Spondylus , May 25, 2000, coll. SISV, PSS & JRBZ). Oaxaca ( Mexico), UMAR-Poly 92 (15º51’N, 97º04’W, Puerto Escondido, on Spondylus calcifer, VD , 6–10 m, July 4, 2004, coll. SS); UMAR-Poly 93, 2 spec. (15º44’40”N, 96º07’43”W, La Entrega beach, Huatulco, on S. calcifer, Aug., 2004 , coll. MSGM).

Diagnosis. Tube rough and thick-walled, white, with three longitudinal ridges, generally, middle ridge short and flanked by pair of ridges forming two denticulate crests, lacks peristomes or alveoli. Opercular peduncle and operculum completely calcified, enclosed by thin fleshy layer terminating at opening of funnel with number of glandular areas, approximately equal, to the number of marginal spines ( Figs 10A, D). Operculum peduncle with four longitudinal grooves ( Figs 10A, C-D). Operculum ending in deep funnel, pinkish, radial ridges generally well developed, with many irregular teeth ( Figs 10A–D). Thoracic membrane large, extending to 7 th thoracic chaetiger and forming ventral apron. Collar with bundles of few chaetae, mostly hooded (limbate) chaetae, remaining ones with proximal denticulate region, as “ Spirobranchus ” chaetae. Thorax with hooded (limbate) chaetae.

Habitat. Depth: 6 to 30 m; ten Hove (1973) recorded 13– 53 m. On rocks and on the spiny oyster Spondylus calcifer .

Distribution. Amphi-American. Caribbean Sea; Western coast of Baja California Peninsula ( Mexico) to Panama and Colombia (ten Hove 1973).

Taxonomic remarks. The opercula of the specimens revised here are similar to those figured by ten Hove (1973, Figs 25–29); however, some specimens have an opercular peduncle as the shortest ( Fig. 10D) which may represent an example of the regeneration of the operculum.