Sertularella gayi Lamouroux 1821

Sertularella gayi (Lamouroux, 1821)

Fig. 94 A–C

See Medel & Vervoort (1998) for a complete synonymy.

Material examined. HCUS-S 101 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Gili 1986; Ramil & Vervoort 1992; Ramil et al. 1992):

Hydroid. Hydrorhiza strong, radially ramified; colonies erect, pinnate, well developed, dioecious; hydrocaulus polysiphonic, up to ca 160 mm, secondary branches sometimes present, internodes thecate, separated by oblique nodes alternatively directed to the left and the right; hydrothecae present in the monosiphonic parts of the hydrocaulus and hydrocladia; lateral, alternate, urn-shaped, tubular, swollen basally and slightly narrower distally, usually with the margin tilted outwards, in abcauline direction, aprox. 1/2 of the adcauline wall adnate to the internode, old hydrothecae with many times renovations, with thickened abcauline wall, adcauline wall often with transverse undulations, more or less pronounced, rim of hydrotheca with 4 equal marginal cusps, hydrothecal operculum of 4 triangular flaps attached in rounded embayments between marginal cusps. Gonothecae on both axis and side-branches, just below hydrothecae, elongated, ovoid, with distal half annulated, aperture circular, usually flanked by 2 broad cusps, typically one larger than the other, 3–4 cusps may occur; acrocyst external to female gonothecae.

Cnidome. Microbasic mastigophores.

Habitat type. Frequent in fine sand grounds, recorded from subtidal al least to edge of continental shelf, from 10 m to at least 1200 m (Medel et al. 1991; Ramil & Vervoort 1992).

Substrate. Shells of Mollusca, Tunicata, Gorgonacea and other, on tubes of polychaetes, basally with Opercularella panicula, algae, concretions.

Seasonality. January–October (for a review see Bouillon et al. 2004); April, May, August–December (De Vito 2006; this study) in Salento waters.

Reproductive period. January, May, September (Bouillon et al. 2004).

Distribution. Eastern Atlantic, Mediterranean (Medel & López-González 1996; Medel & Vervoort 1998; Bouillon et al. 2004; Gravili et al. 2008a).

Records in Salento. Rare at Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; this study).

Remarks. The regular and ramified, pinnate structure of the colony may at times, by the development of polysiphonic branches, become irregular (for more details see Ramil & Vervoort 1992).

References. Picard (1956, 1958a), García-Corrales et al. (1980), Gili (1986), Medel et al. (1991), Ramil & Vervoort (1992), Ramil et al. (1992), Medel & López-González (1996), Medel & Vervoort (1998), Bouillon et al. (2004); De Vito (2006), Gravili (2006), Gravili et al. (2008a).