Halecium labrosum Alder 1859

Halecium labrosum Alder, 1859

Fig. 62 A–D

See Schuchert (2005b) for a complete synonymy.

Material examined. HCUS-S 0 69 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Schuchert 2005b):

Hydroid. Colonies erect; hydrocauli polysiphonic, up to 100 mm high, irregularly branched, mainly in one plane, internodes provided with irregular undulations, each inserted laterally at distal part of previous internode with characteristic upward curve near base, nodes alternately oblique; hydrotheca at the end of internode, short, with everted rim recurved downwards, renovations frequent; gonothecae borne on short 1–2 ringed pedicels, without gonophoral hydranths, male ones oval and elongated, with small distal aperture, females ovoid, large, aperture on short collar.

Cnidome. Microbasic mastigophores.

Habitat type. Hard-bottom, coralligenous, semi-dark cave (depth range: 0–40 m, but also down to 700 m) (Boero & Fresi 1986; Gili 1986; Puce et al. 2009; Mastrototaro et al. 2010).

Substrate. Algae, concretions, hydroids, bryozoans, barnacles, cold water corals.

Seasonality. September–November (Boero & Fresi 1986); April, May, July–August, November–February (Llobet i Nidal 1987); February (Puce et al. 2009) in the western Mediterranean; April, September (Mastrototaro et al. 2010), December (this study) in Salento waters.

Reproductive period. September–November (Boero & Fresi 1986); September, October, December, February (Bouillon et al. 2004) in the Mediterranean Sea.

Distribution. Arctic-boreal species, eastern and western Atlantic, Mediterranean, northern Pacific (Cornelius 1995; Medel & López-González 1996; Bouillon et al. 2004; Schuchert 2005b).

Records in Salento. Rare at S. Maria di Leuca (Mastrototaro et al. 2010).

Remarks. For Schuchert (2005b), following Broch (1918), it is possible that at least some Mediterranean records of H. labrosum belong to other species of Halecium, particularly to H. mediterraneum.

References. Picard (1958a), Rossi (1961, 1971), Sarà et al. (1978), Morri & Bianchi (1983), Boero & Fresi (1986), Gili (1986), Llobet et al. (1986, 1991), Llobet i Nidal (1987), Gili et al. (1989), Medel & López-González (1996), Bouillon et al. (2004), Schuchert (2005b), Puce et al. (2009), Mastrototaro et al. (2010).