Nemertesia antennina (Linnaeus, 1758) Fig. 88 A–C See Ramil & Vervoort (1992) for a complete synonymy. Material examined. HCUS-S 0 95 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula). Description (after Ramil & Vervoort 1992; Cornelius 1995; Medel & Vervoort 1995): Hydroid. Hydrorhiza forming a tangled mass springing from basal part of hydrocaulus; colony erect; hydrocaulus monosiphonic, up to 350 mm high, unbranched, divided into internodes by indistinct transverse nodes, each segment with 1–2 verticils with 4–6 apophyses, each verticil alternate in position with the nearby one, with a mamelon and up to 7 nematothecae on upper surface of each apophysis, coenosarc of the hydrocaulus canaliculated; hydrocladia heteromerously segmented by oblique to transverse nodes, perisarc of the hydrocladia thin, contrary to the thick one of the apophyses, basal-most part of hydrocladia with 2 shorter internodes each bearing one nematotheca; non-hydrothecate segments with one nematotheca (occasionally 2), hydrothecate internodes with one hydrotheca and 3 nematothecae, one median inferior and 2 laterals ones; hydrotheca small, cup-shaped, entirely adnate to the axis, rim even, somewhat sinuous, aperture slightly directed downwards; nematothecae all two-chambered and conical, basal chamber longer than apical, this provided with adcauline embayment, in some colonies, basal chamber of lateral nematothecae rather elongated. Gonothecae borne on the apophyses, male and female similar, ovoid, with ovalate latero-distal aperture. Colours: coenosarc of the hydrocaulus orange-yellowish; hydrocladia colourless; male gonothecal contents white, female orange. Cnidome. Microbasic mastigophores. Habitat type. Sandy bottoms offshore; semi-dark and dark caves, down to 1500 m (Boero & Fresi 1986; Cornelius 1995; Medel & Vervoort 1995). Substrate. On several substrates such as stones, fragments of shells, corals. Seasonality. May–August, October–December (Bouillon et al. 2004); April (Mastrototaro et al. 2010) in Salento waters. Reproductive period. September (Stechow 1923) in the Tyrrhenian Sea. Distribution. Cosmopolitan (Alvarez Claudio 1993; Cornelius 1995; Hirohito 1995; Medel & López- González 1996; Ramil et al. 1998; Bouillon et al. 2004). Records in Salento. Rare at S. Maria di Leuca (Mastrototaro et al. 2010). Other Apulian records: Northern coast (Marano et al. 1991). Remarks. Ramil & Vervoort (1992) gave a detailed description of this species, discussed the variation observed in a large set of material collected by the BALGIM expedition, and provided a list of synonyms. References. Kirchenpauer (1876), Carus (1884), Marktanner-Turneretscher (1890), Broch (1912), Neppi (1917), Stechow (1923), Leloup (1934), Picard (1958a), Riedl (1970, 1991), Rossi (1971), Boero & Fresi (1986), Roca (1986), Marano et al. (1991), Ramil & Vervoort (1992), Alvarez Claudio (1993), Medel & Vervoort (1995), Medel & López-González (1996), Bouillon et al. (2004), Mastrototaro et al. (2010).

Published as part of 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, pp. 1-187 in Zootaxa 3908 (1) on pages 124-125, DOI: 10.11646/zootaxa.3908.1.1, http://zenodo.org/record/242729