Sertularella mediterranea Hartlaub, 1901

Gravili, Cinzia, Vito, Doris De, Camillo, Cristina Gioia Di, Martell, Luis, Piraino, Stefano & Boero, Ferdinando, 2015, The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide, Zootaxa 3908 (1), pp. 1-187 : 133-134

Sertularella mediterranea Hartlaub, 1901

Fig. 95 A–C

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

Material examined. HCUS-S 102 (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; Peña Cantero & García Carrascosa 2002):

Hydroid. Hydrorhiza tubular, as ramified stolons; colony erect; hydrocauli monosiphonic, up to 23 mm high, and irregularly branched, divided into thecate internodes by oblique nodes alternatively directed to the left and the right; hydrocladia structure similar to hydrocaulus; hydrothecae tubular, alternate, placed laterally, one per internode, 1/3–1/2 of the adcauline wall adnate, abcauline and adcauline walls not symmetrical, the former usually more or less straight, enlarged distally in a pronounced marginal cusp, the latter swollen basally and narrowing distally, hydrothecal margin tilted upwards in adcauline direction, with 3–5 more or less developed intrathecal projections: when 5, 3 are adcaulinar (one medium, in the same axis of the marginal cusp, and 2 laterals) and 2 are abcaulinar (lateral to the cusps). Gonothecae elongated, ovoid, transversally ringed, narrowed distally, with 3–4 apical cusps, embryos brooded in gelatinous acrocyst of female gonothecae. Colours: hydrocauli yellow or light brown.

Cnidome. Microbasic mastigophores.

Habitat type. From the tidal level to about 40 m depth ( Stechow 1919 as S. polyzonias ; García Carrascosa 1981; Medel et al. 1991).

Substrate. Various species of algae, Posidonia oceanica , barnacles, but has also been seen to grow directly on rocks and various invertebrates such as hydroids, molluscs, gorgonids, sponges, bryozoans, and polychaete tubes.

Seasonality. All year ( Boero & Fresi 1986; De Vito 2006; this study), May, November, December (Puce et al. 2009) in several localities of the Mediterranean Sea.

Reproductive period. January ( Stechow 1919; Gili 1986); February ( Boero & Fresi 1986); April ( Stechow 1919; Boero & Fresi 1986; Gili 1986; De Vito 2006; this study), May ( Stechow 1919; Medel et al. 1991), July ( Medel et al. 1991), August ( Boero & Fresi 1986), October (De Vito 2006; this study); November ( Broch 1933; De Vito 2006; this study), and December ( Boero & Fresi 1986; De Vito 2006; this study) in several localities of the Mediterranean Sea. According to the available data, S. mediterranea seems to be fertile throughout the year at temperate latitudes ( Peña Cantero & García Carrascosa 2002; Bouillon et al. 2004).

Distribution. Eastern Atlantic, Mediterranean (Ramil & Vervoort 1992; Medel & López-González 1996; Medel & Vervoort 1998; Peña Cantero & García Carrascosa 2002; Bouillon et al. 2004; Gravili et al. 2008a).

Records in Salento. Moderately frequent in the following localities: Costa Merlata ( Fraschetti et al. 2002); Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; this study).

Remarks. There is a great variability throughout the colony, the marginal abcauline cusp may be not enlarged, and the aperture of the hydrotheca may vary its orientation within the same colony, the abcauline wall may be undulated. This species has been described extensively, discussed and figured by Ramil et al. (1992).

References. Neppi (1917, 1921), Stechow (1923), Broch (1933), Rossi (1950) as S. polyzonias ; Riedl (1959), Picard (1956) as S. ellisi f. mediterranea ; Cornelius (1979, 1995) as S. gaudichaudi ; García-Corrales et al. (1980) as S. picta ; García Carrascosa (1981); Isasi (1985); Boero & Fresi (1986) as S. gaudichaudi f. mediterranea ; Gili (1986), Medel et al. (1991); Ramil & Vervoort (1992), Ramil et al. (1992), Altuna (1994), El-Beshbeeshy (1994), Medel & López-González (1996), Medel & Vervoort (1998), Fraschetti et al. (2002), Peña Cantero & García Carrascosa (2002), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Gravili et al. (2008a), Puce et al. (2009), Bianchi et al. (2011).

Figures

FIGURE 95. Sertularella mediterranea: A, general view of a colony; B, parts of stem with male gonotheca, and C, female gonotheca (B, C same scale bar) (drawn by L. Basso). Scale bars: A, 2.0 mm; B, C, 1.0 mm.