Eudendrium capillare Alder 1856

Eudendrium capillare Alder, 1856

Fig. 15 A–E

See Schuchert (2008b) for a complete synonymy.

Material examined. HCUS-S 0 18 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Marques et al. 2000a, b; Schuchert 2008b, 2012):

Hydroid. Hydrorhiza stolonal; colonies erect, small and slender, up to 4 cm high; hydrocauli monosiphonic, irregularly to more or less alternately branched, perisarc thicker basally and becoming thinner towards distal end, terminating at groove around base of hydranths, with several annulations basally on hydrocladia and pedicels of hydranths, but also with irregularly placed annulations elsewhere; hydrocladia in turn alternately to irregularly branched; hydranths on long and bent pedicels; hypostome large and flared; about 20 (15–24 range) filiform tentacles with tentacular nematocysts confined to proximal 3/4 of tentacles, arranged in regular rings. Gonophores as fixed sporosacs, borne on hydranths, females in a whorl on hydranths with partially atrophied tentacles, spadix unbranched, curving over egg, 5– 12 eggs per blastostyle; males borne like tuft on blastostyle without tentacles at all stages, 12–15 and more per blastostyle, with up to 3 chambers each, terminal one with an apical tubercle, on atrophied polyps. Colours: perisarc yellowish to transparent; hydranths either not much coloured, cream to light rose-orange or red.

Cnidome. Microbasic euryteles (6.7–7.6 x 2.5–3.2 µm), one end tapering, not concentrated in a basal ring; isorhiza capsules with two blunt ends, same size as euryteles, numbers present rather variable, may be missing.

Habitat type. Occurs usually from 0 to 80 m depth, grows on variety of solid substrata (rocky cliffs, hardbottom, coralligenous, semi-dark cave), and other animals and algae (Boero & Fresi, 1986; Schuchert, 2012).

Substrate. Posidonia rhizomes, algae, hydroids, bryozoans, mussels, barnacles.

Seasonality. Along the Mediterranean French coast (Stechow 1919) from April to May, August; in the Ligurian Sea (Boero & Fresi 1986; Puce et al. 2009) present throughout the year; May–August (this study).

Reproductive period. From April to November, but the reproductive period is likely longer than indicated by these intervals (see Schuchert 2008b).

Distribution. Eastern and western Atlantic, Indian Ocean, eastern and western Pacific (Bouillon et al. 2004; Gravili et al. 2008a; Schuchert 2008b).

Records in Salento. Common at: S.ta Caterina, La Strea (Presicce 1991); Costa Merlata (Fraschetti et al. 2002); Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; this study).

Remarks. See Marques et al. (2000a) concerning the validity of the records of this species in the Medìterranean Sea.

References. Picard (1958a), Rossi (1961, 1971), Schmidt (1973), Millard (1975), Boero (1981a, b), Boero & Fresi (1986), Llobet et al. (1986), Marinopoulos (1992), Ramil & Vervoort (1992), Medel & López-González (1996), Morri & Bianchi (1999), Marques et al. (2000a), Schuchert (2001a, 2008b, 2012), Fraschetti et al. (2002), Peña Cantero & García Carrascosa (2002), Bouillon et al. (2004), Puce et al. (2005a, 2009), De Vito (2006), Gravili (2006), Gravili et al. (2008a).