Sertularia perpusilla Stechow, 1919

Fig. 97 A, B

See Peña Cantero & García Carrascosa (2002) for a complete synonymy.

Material examined. HCUS-S 104 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Boero 1981a; Gili 1986):

Hydroid. Hydrorhiza stolonal, colonies erect; hydrocaulus up to ca 7 mm, usually unbranched, internodes thecate excepting basal parts, separated by distinct or indistinct oblique nodes; hydrothecae opposite, touching frontally, tubular and curved outwards, forming 80º–90º angle with the axis, adcauline wall 1/2 adnate to the axis, margin with 3 cusps, 2 laterals and one abcauline, operculum with 2 valves. Gonothecae elongated-ovoid, with transverse ribs and 4 small apical cusps.

Cnidome. Microbasic mastigophores.

Habitat type. Littoral from 1 to about 70 m depth (Boero 1981a; Boero & Fresi 1986; Roca 1986).

Substrate. This species is an exclusive epibiont of Posidonia oceanica .

Seasonality. Present all year (Boero & Fresi 1986), April (Moura 2011; this study), May (Giovannetti et al. 2010), August (Bianchi et al. 1993a; Galea 2007), and September (Bianchi et al. 1993a; Galea 2007; Giovannetti et al. 2010) in several localities of the Mediterranean Sea.

Reproductive period. March (Stechow 1919), June (Stechow 1919; Rossi 1950), July (Broch 1933; Gili 1986), August (Stechow 1919; Broch 1933; Peña Cantero & García Carrascosa 2002), and September (Boero & Fresi 1986) in several localities of the Mediterranean Sea.

Distribution. Endemic to Mediterranean (Marinopoulos 1979; Medel & López-González 1996; Peña Cantero & García Carrascosa 2002; Bouillon et al. 2004; Soto Ãngel & Peña Cantero 2013).

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

Remarks. For more details about the ecology of this species see Peña Cantero & García Carrascosa (2002).

References. Babic (1910) as S. mediterranea; Stechow (1919); Broch (1933), Billard (1936), Picard & Roch (1949), Picard (1952), Rossi (1971), Marinopoulos (1979), Boero (1981a, b), Fresi et al. (1982), Boero et al. (1985), Boero & Fresi (1986), Gili (1986), García-Rubies (1987, 1992), Roca (1987), Piraino & Morri (1990), Hughes et al. (1991), Morri et al. (1991), Roca et al. (1991), Medel & López-González (1996), Piraino et al. (1999), Peña Cantero & García Carrascosa (2002), Bedini et al. (2003), Bouillon et al. (2004), Gravili (2006), Galea (2007), Gravili et al. (2008a), Giovannetti et al. (2010), Moura (2011).