Watersipora subtorquata (d’Orbigny, 1852) Introduced

Ruiz-Velasco, Sofía, Ros, Macarena, Guerra-García, José M. & López-Fé, Carlos M., 2025, Fouling bryozoans in recreational marinas of the Canary Islands (North-Eastern Atlantic) with new records of non-indigenous and cryptogenic species, Zootaxa 5656 (1), pp. 1-63 : 43-45

Watersipora subtorquata (d’Orbigny, 1852) Introduced

( Fig. 22 ; Table 22)

Cellepora subtorquata d’Orbigny, 1852: 399 . Watersipora subtorquata : Taylor & Gordon 2002: 536, fig. 1; Abdel-Salam & Ramadan 2008: 9, fig. 3; Vieira et al. 2014a: 155,

figs 1–5, 12–16, 18–24, 67, 70. Non Watersipora subtorquata : Gordon & Mawatari 1992: 31, fig. 8E; Ryland et al. 2009:

55, figs 1, 3, 4A, B, E, F, 5. (A more extensive and detailed list of synonymies can be found in Vieira et al. 2014a).

Figured material. Garachico (20/06/23) (1C on buoy) ( MNCN 25.03/4470).

Other material examined. Marina Tenerife (19/06/23) (1C on buoy), Las Galletas (19/06/23) (3C on buoy), Pasito Blanco (26/06/23) (1C on buoy), Taliarte (26/06/23) (1C on buoy), Big Canary Sports Dock (27/06/23) (2C on buoy), Morro Jable (27/06/23) (1C on buoy), Gran Tarajal (28/06/23) (1C on buoy), Corralejo (28/06/23) (1C on buoy), Puerto Calero (29/06/23) (1C on buoy), Playa Blanca (29/06/23) (1C on buoy), Marina Lanzarote (29/06/23) (1C on buoy).

Description. Encrusting orange and black colonies, unilamellar on flat substrata and multilamellar on irregular substrata ( Fig. 22A ), sometimes becoming erect. Zooids subrectangular or oval, twice as long as wide and separated by marked lateral walls ( Fig. 22B, C ). Frontal wall slightly convex or flat, showing round pseudopores ( Fig. 22D ). Orifice large, wider than long, with oval or subcircular, well-defined U-shaped proximal sinus, triangular condyles directed distomedially ( Fig. 22E ). Operculum with a parallel-sided dark band in the centre and two lucidae located proximally ( Fig. 22C ), adjacent to the condyles. Oral spines, avicularia and ovicells absent.

Remarks. Watersipora species are difficult to identify morphologically due to the lack of easily recognizable features, such as oral spines, avicularia and ovicells ( Ryland et al. 2009), often leading to misidentifications. For instance, Watersipora subatra ( Ortmann, 1890) has been often misidentified as W. subtorquata ( Ryland et al. 2009; Mackie et al. 2012; Gauff et al. 2023). To avoid this widespread confusion regarding the Watersipora genus, we focused our identification on detailed descriptions provided by Vieira et al. (2014a). These authors mentioned that W. subtorquata is characterized by (1) a suborbicular orifice with triangular condyles, (2) an operculum with a parallel-sided dark band with two lucidae adjacently placed to the condyles, and (3) the absence of intrazooidal septum proximolateral to the orifice with some small pores. These features are clearly observed in our samples. Arístegui (1984b) recorded Watersipora subovoidea (d’Orbigny, 1852) (now Watersipora cucullata ( Busk, 1854)) in the Canary Islands. Nevertheless, the description of the material that he provides resembles Watersipora souleorum Vieira, Spencer Jones & Taylor, 2014 , with similar measurements, an oval orifice including a U-shaped sinus, and lacking the notable triangular projections of W. cucullata .

Distribution and status. The native range of Watersipora subtorquata is confused due to several misidentifications with similar species. This species was originally described from Brazil. Tropical South-Western Atlantic ( Vieira et al. 2014a), the Caribbean region ( Soule & Soule 1976; Mackie et al. 2006) and the Indo-West Pacific Ocean (Canning-Clode et al. 2013) have been proposed as possible native regions for this species. Watersipora subtorquata is widely distributed, appearing in the Indo-Pacific, the Atlantic, the Mediterranean Sea, the Red Sea, and the Arabian Sea ( Vieira et al. 2014a; McCann et al. 2019). Records of the introduction of these species in the Macaronesia region go back to the 19 th century, from the Azores and Cape Verde ( Jullien & Calvet 1903). Nevertheless, those reports may be doubtful ( Castro et al. 2023). The voucher material collected by Jullien and Calvet (1903) from the Azores in 19 th century, was not W. subtorquata , but a new species, Watersipora souleorum Vieira, Spencer Jones & Taylor, 2014 ( Vieira et al. 2014a). Nonetheless, more recently Watersipora subtorquata has been reported from all Macaronesian archipelagos, in the Azores ( Vaz-Pinto et al. 2014; Micael et al. 2019), Madeira ( Canning-Clode et al. 2013a), the Canary Islands ( Moro et al. 2018) and more recently in Cape Verde ( Castro et al. 2023). Specifically in the Canary Islands, this species was not detected in thorough studies of bryozoans such as Arístegui (1984b) and Cook (1968), implying that W. subtorquata probably is a more recent introduction ( Moro et al. 2018). Due to the prior absence of this species in the Canarian archipelago and its detection only in port environments, we consider this species introduced in this area.

Figures

FIGURE 22. Watersipora subtorquata (d’Orbigny, 1852) (MNCN25.03/4470). A. Colonies in a buoy in Garachico marina. B. Group of zooids through stereomicroscope and C. through optical microscope. D. Colony view through SEM. E. Primary orifice. Scale bars: A = 1 cm; B, E = 40 µm; C = 20 µm; D = 400 µm.