Mörch, 1863 : 405 Spirobranchus incrassatus Margaritifera Pinctada Spirobranchus incrassatus S. giganteus Spirobranchus giganteus S. incrassatus Porites lobata Dana Spirobranchus giganteus corniculatus Spirobranchus spinosus Salcedo-Martínez et al . 1988 : 84 Rodríguez Cajiga 1993 : 502 New records of sabellids and serpulids (Polychaeta: Sabellidae, Serpulidae) from the Tropical Eastern Pacific Bastida-Zavala, J. Rolando Buelna, Alondra Sofía Rodríguez León-González, Jesús Angel De Camacho-Cruz, Karla Andrea Carmona, Isabel Zootaxa 2016 4184 3 401 457 4Z7S5 Kroyer Kroyer [151,572,788,814] Polychaeta Serpulidae Spirobranchus Animalia Sabellida 33 434 Annelida species incrassatus     Spirobranchus incrassatusKrøyer[in]  Mörch, 1863: 405, pl. 11, Figs 21–23. Type locality: Pacific of Colombia, on  Margaritiferasp. (now  Pinctadasp.).    Spirobranchus incrassatus.— Ehlers 1887: 294–295, pl. 57, Fig. 16; pl. 58, Fig. 1–5(Acapulco, Guerrero); Bush 1905: 236, pl. 34, fig. 24, pl. 37, Figs 25, 34 (Gulf of California, on  Margaritiferasp., now  Pinctadasp.); Rioja 1941b: 738 (Acapulco, Guerrero, on rocks); Steinbeck & Ricketts 1941: 367–369 (Cabo San Lucas, Baja California Sur; encrusting on rocks); Rioja 1942: 132–133, Figs 22–31 (Acapulco, Guerrero; description of juvenile specimens); Rioja 1947a: 216 (Topolobampo, Sinaloa, on rocks and shells); Salazar-Vallejo 1989b: 200 (Mexican coasts, checklist); Gómez et al. 1997: 1071 (Puerto Ángel Beach, Tangolunda Beach and Cacaluta Beach, Oaxaca, on rocks and coral); Fiege & ten Hove 1999: 362–363, Fig. 4(  Spirobranchus incrassatusas part of  S. giganteuscomplex sensu stricto); Salazar-Vallejo & Londoño- Mesa 2004: 56 (Tropical Eastern Pacific, checklist); Bastida-Zavala 2008: 49, Figs 12C-E (Baja California Sur, Sinaloa, Colima, Guerrero and Oaxaca; 4–17 m); Bastida-Zavala 2009: 542, Fig. 4F (identification key for Tropical America); ten Hove & Kupriyanova 2009: 98 (worldwide serpulid checklist); Bastida-Zavala et al. 2013: 349 (Oaxaca, checklist); Morales de Anda et al. 2014: 126 (Navidad Bay, Jalisco); Villalobos-Guerrero et al. 2014: 107 (Sinaloa, checklist).    Spirobranchus giganteus(not  Pallas, 1766).—  Monro1933b: 1080 ( Taboga Islandand Perlas Islands, Panamá; Gorgona Island, Colombia; Santiago[ James], Floreana[ Charles] and Isabela[ Albemarle] Islands, Galápagos, on pier floats, coral, shorepools in lava, fine gravel in pools;  0–7 m);   Rioja1963: 220 (Mazatlán, Sinaloa; Zihuatanejo, Guerrero; and Ballena Island, Baja  CaliforniaSur);  ten Hove1970: 16–18, Figs 46–47, 58–59, 61–62 (synonymized several records of  S. incrassatusfrom the Tropical EasternPacific); Kudenov 1980: 123 ( CaboPulmo Reef, Baja  CaliforniaSur);   Salazar-Vallejo1989b: 200 ( Mexicancoasts, checklist);  Bastida-Zavala1995: 25–26 ( Cabo Pulmo Reef, Baja  CaliforniaSur, on coral;  4–17 m); López-García et al. 1997: 66 ( Coiba Island, Panamá, on live corals as  Porites lobataDana); Gotshall 1998: 91, Fig. 26 (field guide of the Gulf of California);  Salazar-Vallejo & Londoño-Mesa 2004: 56 (Tropical EasternPacific, checklist); Kerstitch & Bertsch 2007: 38, Fig. 62 (field guide of the Gulf of California); Villalobos-Guerrero et al. 2014: 107 ( Sinaloa, checklist).   Spirobranchus giganteus corniculatus(not Grube, 1862).— Hernández-Alcántara et al. 2003: 9 (Socorro Island; Ballena Island and Espíritu Santo Island, Baja California Sur, checklist); Salazar-Vallejo & Londoño-Mesa 2004: 56 (Tropical Eastern Pacific, checklist).    Spirobranchus spinosus(not Moore, 1923).—  Salcedo-Martínez et al. 1988: 84(Zihuatanejo, Guerrero; 2–9 m);  Rodríguez Cajiga 1993: 502(Barra de Navidad, Jalisco).   Material examined.18 specimens.    Baja  CaliforniaSur:  UANL7898, 8spec. ( Puerto Escondido, sta. 2: 25°48’53.1”N, 111°18’40.5”W,  April 2, 2011, coll. JAL & ARB);   UANL7899( Puerto Escondido, sta. 3: 25°48’51.7”N, 111°18’41.2”W,  April 2, 2011, coll. JAL & ARB);   UANL7900(  Marina de La Paz, sta. 1: 24°09’17.7”N, 110°19’32.3”W,  April 3, 2011, coll. JAL & ARB, as  Spirobranchussp.).   Oaxaca:UMAR-POLY 807, 8 spec. (Puerto Ángel, pier, May 20, 2007, coll. FCC & SRH); UMAR-POLY 808, 3 spec. (La India Beach, Huatulco, on  Spondylus calcifer[now  S. limbatus], December 3, 2005, coll. JHB); UMAR-POLY 809 (Conejos Bay, Huatulco, June 11, 2005, coll. JHB & GNL).  Habitat.Intertidal to subtidal ( 17 m, Bastida-Zavala 1995). Most specimens revised here were from anthropogenic substrates in marinas and ports (from La Pazand Puerto Escondido, Baja CaliforniaSur, and from Puerto Ángel, Oaxaca). However, previously it was found on live (  Porites lobata) and dead coral (  Pocillopora verrucosa), on spiny oyster  Spondylus limbatusand  Pinctada, on rock pools, and on pier piles (Bastida-Zavala 2008). Fouling species.   Distribution.Tropical EasternPacific. Baja CaliforniaSur(  México) to  Panamáand Colombia(Krøyer [in] Mörch 1863; Ehlers 1887; ten Hove 1970; Bastida-Zavala 1995).   Remarks.  Spirobranchus incrassatuswas found both in natural and anthropogenic substrates. It is a fouling species with the potential to be introduced to other tropical regions by ships. The species was confused several times with  S. giganteus, a Caribbean species (see remarks in Bastida-Zavala 2008).  Hernández-Alcántara et al. (2003: 9) list Treadwell’s (1914) record of  Spirobranchus quadricornis( Grube, 1878)from Santa Catalina Island, Baja California Sur; however, this is a mistake, the record of Treadwell (1914)corresponds to Avalon, in Santa Catalina Island, Southern California, and the material most likely belongs to  S. spinosus. 1324654083 Panama Pallas 4 Taboga Island Monro 33 434 1 Santiago 1324654092 Iceland Rioja 33 434 1 Rioja 1324654079 ten Hove Iceland Eastern 33 434 1 Eastern 1324654075 Panama Salazar-Vallejo 11 Bastida-Zavala Mexican 33 434 1 California Sur 1324654089 Panama Eastern 33 434 1 Eastern 1324654070 Panama Sinaloa 33 434 1 Sinaloa 1324654093 2011-04-02 UANL, ARB 25.814749 Puerto Escondido 1 -111.31126 33 434 UANL 7898, 8 1 Baja California Sur 1324654088 2011-04-02 UANL, ARB 25.81436 Puerto Escondido 1 -111.31145 33 434 UANL 7899 1 Baja California Sur 1324654082 2011-04-03 UANL, ARB 24.154917 Marina de La Paz 1 -110.32564 33 434 UANL 7900 1 Marina de La Paz