Pyrgopolon ctenactis (Mörch, 1863)

(Figures 7, 13 D)

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

Sclerostyla ctenactis .— Bush 1905: 224 (type designation); Wrigley 1951: 184–185, fig. 38 (Octavia Bay, Pacific of Colombia); ten Hove 1973: 6–12, Figs 1–4, 7, 20–31, pls. 1, 3a–b, 3, 7 (revision of the genus); de León-González 1990, fig. 2 a–f ( Punta San Juanico and Cabo San Lorenzo, Baja California Sur; 27–30 m) ; de León-González et al. 1993: 879 (Puerto Escondido Bay, Baja California Sur, epifauna on the oyster “ Spondylus princeps unicolor ”; 30 m) ; Salazar-Vallejo & Londoño-Mesa 2004: 55 (Tropical Eastern Pacific, checklist).

Pyrgopolon ctenactis .— Jäger 1993: 95 (new combination, synonymy of the genera Sclerostyla Mörch and Hepteris Regenhardt with Pyrgopolon); Bastida-Zavala 2008: 42, Figs 10 A–D (Baja California, Baja California Sur, Guerrero and Oaxaca; 6– 30 m); Bastida-Zavala 2009: 541, Fig. 3 V (identification key for Tropical America); ten Hove & Kupriyanova 2009: 88 (worldwide serpulid checklist); Bastida-Zavala et al. 2013: 349 (Oaxaca, checklist).

Material examined. Eleven specimens.

Oaxaca: UMAR-POLY 806, 11 spec. (La India Beach, Huatulco, on Spondylus calcifer [now S. limbatus], December 3, 2005, coll. JHB).

Habitat. Subtidal (6–30 m, de León-González et al. 1993; Bastida-Zavala 2008); ten Hove (1973) recorded 13– 53 m. On the spiny oysters “ Spondylus princeps unicolor ” (de León-González et al. 1993) and S. limbatus .

Distribution. Amphi-American. Caribbean Sea; western coast of Baja California (Guadalupe Island), western coast of Baja California Sur (Cabo San Lázaro and Punta San Juanico), Gulf of California (Puerto Escondido), Mexican south Pacific (Acapulco, Puerto Escondido and Huatulco) and Pacific of Colombia (Octavia Bay) (ten Hove 1973; de León-González 1990; de León-González et al. 1993; Bastida-Zavala 2008). The record by Bastida- Zavala (2008) of the Pacific of Panamá is a mistake.

Remarks. Pyrgopolon ctenactis is recorded from a few localities in the Tropical Eastern Pacific. The Pacific population of this subtidal species might be a Pleistocene relict, the taxon was never reported from ship hulls, thus dispersion as fouling of ships is unlikely. However, a thorough review and comparison between Atlantic and Pacific populations is necessary, including a DNA analysis.