Hydroides sanctaecrucis Krøyer [in] Mörch, 1863

(Figures 6, 12 E)

Hydroides (Eucarphus) sanctae-crucis Krøyer [in] Mörch, 1863: 378 –379, pl. 11, Fig. 12. Type locality: Saint Croix, Caribbean Sea.

Eupomatus sanctae crucis .— Rioja 1958: 262 –264 (Verde Island and Santiaguillo Island, Veracruz).

Hydroides sanctaecrucis .— Long 1974: 28 ( Oahu, Hawaii, 15 m, with little coverage on test panels); Bastida-Zavala & ten Hove 2002: 148–151 (first record from the Pacific coast of Panamá; 5 m) ; Bastida-Zavala & ten Hove 2003: 101–102, Figs 19P–Q ( Oaxaca and Panamá; 0–1 m) ; Salazar-Vallejo & Londoño-Mesa 2004: 54 (Tropical Eastern Pacific, checklist); Cohen 2006: 167 (possible introductions from the Atlantic to the Pacific via of the Panamá Canal); Lewis et al. 2006: 666– 669 (establishment in northern Australia and Singapore); Okolodkov et al. 2007: 40 (exotic in the Mexican Pacific); Bastida-Zavala 2008: 29, fig. 6R (Oaxaca; 0–1 m) ; Bastida-Zavala 2009: 535–536, Fig. 3 B (identification key for Tropical America); ten Hove & Kupriyanova 2009: 54 (worldwide serpulid checklist); Tovar-Hernández et al. 2012: 18–19 ( La Paz, Baja California Sur, Guaymas, Sonora, and Topolobampo, Sinaloa); Bastida-Zavala et al. 2013: 349 ( Oaxaca, checklist); Bastida-Zavala et al. 2014: 326–327, Fig. 19.1i (exotic in the Mexican Pacific); Tovar-Hernández et al. 2014: 390 ( Marina Palmira, Topolobampo, Sinaloa; Marina Fonatur, Guaymas, Sonora; and Marina La Paz, Baja California Sur); Villalobos-Guerrero et al. 2014: 107 (Sinaloa, checklist); Sun et al. 2015: 76–79, fig. 25 (Northern Territory and Queensland, Australia; intertidal to 1 m; on rocks, fouling of ship’s hulls and other man-made structures).

Hydroides santaecrusis (sic): Dueñas 1981: 99–100, fig. 29A–F (Albornoz, Cartagena Bay, Colombia; on mangrove roots); Quirós-Rodríguez et al. 2013: 91, Table 3 (Córdoba, Colombian Caribbean; on red algae, intertidal).

Eupomatus sanctaecrucis .— Salazar-Vallejo & Londoño-Mesa 2004: 54 (Tropical Eastern Pacific, checklist).

Material examined. 71 specimens.

Sonora: UANL 7883, 2 spec. ( Marina Real, Puerto San Carlos, 27°56’41.7”N, 111°05’35.6”W, July 7, 2011, coll. JAL & ALE).

Baja California Sur: UANL 7882, 42 spec. ( Marina Fonatur, La Paz, 24°07’29.7”N, 110°20’47.1”W, November 14, 2013) ; UANL 7881 ( Marina Puerto Los Cabos, San José del Cabo, sta. 1, 23°03’42.4”N, 109°40’27.8”W, April 4, 2011, coll. ARB & JAL) ; UANL 7880, 2 spec. ( Marina Cabo San Lucas, sta. 1: 22°53’09.1”N, 109°54’38.4”W, April 22, 2010, coll. ARB & JAL).

Oaxaca: UMAR-Poly 780, 4 spec. ( Salina Cruz, angler pier, main dock, sta. 4, 1 m, May 26, 2011, coll. SGM et al.); UMAR-Poly 781, 10 spec. (same, hull of the shrimp boat “ Golfo Pérsico ”, 1 m, May 26, 2011, coll. EVP); UMAR-Poly 782, 10 spec. (Laguna Inferior, San Dionisio del Mar, 16°18’8”N, 94°44’56”W, 0.5 m, salinity= 30.77 PSU, August 30, 2014, coll. CPR).

Habitat. Intertidal to subtidal (5 m, Bastida-Zavala & ten Hove 2002). On anthropogenic substrates in marinas and ports (from Cabo San Lucas and San José del Cabo, Baja California Sur; Puerto San Carlos, Sonora; and Salina Cruz, Oaxaca). On rocks, floats and piers, salinity range 19–37 PSU (Bastida-Zavala & ten Hove 2003). Fouling species.

Distribution. Caribbean Sea, Gulf of Mexico, from Eastern Florida to French Guyana. As exotic species in the Pacific side of Panamá (Bastida-Zavala & ten Hove 2002), Oaxaca (Bastida-Zavala & ten Hove 2003), Gulf of California (Tovar-Hernández et al. 2012), Hawaii (Long 1974), northern Australia and Singapore (Lewis et al. 2006).

Remarks. The first record of Hydroides sanctaecrucis in the Tropical Eastern Pacific was from Panamá, specimens collected in 1972 (Bastida-Zavala & ten Hove 2002); previously, the species was reported from Oahu , Hawaii, collected 1968–1972 (Long 1974). The species was recorded from Oaxaca, collected in 2000 (Bastida- Zavala & ten Hove 2003); from Northern Australia, collected between 1998 and 2001; from Singapore, sampled 2002 (Lewis et al. 2006), moreover, these authors suspect that H. cf. uncinata, as recorded by Sun & Yang (2000, Figs 7 J-L) from the China Sea, might be H. sanctaecrucis; and from Darwin, Northern Territory of Australia in 2014 (Sun et al. 2015). Recently, the species was recorded from several localities in the Gulf of California (Tovar- Hernández et al. 2012).

In Northern Australia and Singapore Hydroides sanctaecrucis is an invasive species which reaches high abundances in several areas (Lewis et al. 2006). Although the species has been present in Oaxaca and Los Cabos marinas for several years, its abundance is not very high, approximately 25–50 specimens/m2.

Lakshmana Rao (1969: 9, Plate 6, Figs A–H) described Hydroides vizagensis Lakshmana Rao, 1969 from Visakhapatnam, northeastern of India; however, the description and the figure of the operculum correspond to the H. sanctaecrucis description (opinion shared with Lena Kupriyanova and Harry ten Hove, pers. comm. 2016). Would need revise the type specimens (deposited in Andhra University, India) for confirm that suspicion.