Eudendrium ramosum Linneaus 1758

Eudendrium ramosum (Linneaus, 1758)

Fig. 22 A–D

See Schuchert (2008b) for a complete synonymy.

Material examined. HCUS-S 0 27 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula). Description (based on our own observations; Marques et al. 2000a; Schuchert 2008b, 2012):

Hydroid. Colonies erect, up to 175 mm; hydrocauli basally polysiphonic, sometimes slender and flexuous with roughly alternate hydrocladia, sometimes stiff and bushy, branching irregularly, with smooth perisarc, annulated above origin of hydrocladia and also elsewhere; hydrocladia monosiphonic; hydranths on basally ringed pedicel; hypostome flared; with 14–30 filiform tentacles. Gonophores as fixed sporosacs, borne on hydranths with atrophied tentacles to a varying degree, females up to seven per gonozooid, with unbranched spadix, encapsulated embryos attached along pedicel; males up to five per hydranth, with 1–2 chambers. Colours: female gonophores orange-red; male ones with red spadix. Colour: hydranths reddish.

Cnidome. Large heterotrichous microbasic euryteles (22.2–28.0x8.7–13.3 µm) on hypostome, lower part of hydranth, and on hydrocaulus; shaft thin, about 2/3 to 3/4 length of capsule, increasing in diameter distally but not coiled when undischarged; small heterotrichous microbasic euryteles on tentacles and ectoderm (5.8x2.7 to 8.4x4.2 mm).

Habitat type. The colonies grow on several solid substrata, such as hard bottom biogenic banks and coralligenous ledges (Rossi 1961; Boero 1981a, b, 1983; Marinopoulos 1981; Boero & Fresi 1986; Roca et al. 1991; Morri & Bianchi 1999; Morri et al. 1999; Piraino et al. 1999; Faucci & Boero 2000; Puce et al. 2009). Along the European coasts occurring usually from shallow depths to about 80 m (Peña Cantero & García Carrascosa 2002).

Substrate. Rock, concretions, algae, Posidonia rhizomes, Cymodocea nodosa meadow, hydroids, barnacles, sponges (Ircinia sp.).

Seasonality. In the Ligurian Sea (Boero & Fresi 1986; Puce et al. 2009), and in Salento waters (De Vito 2006; this study) colonies occur all year.

Reproductive period. In the western Mediterranean Sea from July to February (Boero & Fresi 1986), September (Marques et al. 2000a; Puce et al. 2009), July, August (Peña Cantero & García Carrascosa 2002); in Salento waters from March to June (De Vito 2006; this study).

Distribution. Cosmopolitan (Boero & Cornelius 1987; Morri et al. 1991; Marinopoulos 1992; Medel & López-González 1996; Marques et al. 2000a, b; Schuchert 2001a, 2008b; Peña Cantero & García Carrascosa 2002; Vervoort 2006; Gravili et al. 2008a).

Records in Salento. Moderately frequent in the following localities: La Rotonda (Presicce 1991); Porto Cesareo (Faucci & Boero 2000); Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; Piraino et al. 2013; this study).

Remarks. The colonies are stout in shallow water and more slender in deeper waters (Boero & Fresi 1986). Schuchert (2008b) synonymized E. elsaeoswaldae Stechow, 1921 with E. ramosum (Linnaeus, 1758).

References. Rossi (1961, 1971), Millard & Bouillon (1973, 1974), Millard (1975), Boero (1981b), Boero & Fresi (1986), Boero & Cornelius (1987), Marinopoulos (1990, 1992), Morri et al. (1991), Riedl (1991), Roca et al. (1991), Ramil & Vervoort (1992), Medel & López-González (1996), Faucci & Boero (2000), Marques et al. (2000a, b), Schuchert (2001a, 2008b, 2012), Peña Cantero & García Carrascosa (2002), Bouillon et al. (2004), De Vito (2006), Vervoort (2006), Gravili (2006), Gravili et al. (2008a), Puce et al. (2009), Bianchi et al. (2011), Piraino et al. (2013).