Halecium beanii (Johnston, 1838)

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 : 88-89

Halecium beanii (Johnston, 1838)

Fig. 61 A–D

See Schuchert (2005b) for a complete synonymy.

Material examined. HCUS-S 0 68 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Medel & Vervoort 2000; Schuchert 2001a, 2005b):

Hydroid. Colonies erect, up to ca 250 mm; hydrocauli polysiphonic but becoming monosiphonic distally, irregularly branched; hydrocladia alternate, in the same plane, flexuose, varied in length, some of them branched, originating from base of hydrothecae, terminal parts of the axis and hydrocladia separated into internodes by means of slightly oblique nodes; hydrothecae shallow, with almost parallel walls, alternate, borne laterally at upper part of internodes, becoming axillary, primary hydrotheca sessile, but with frequent renovation, all with smooth and short hydrophores of similar length; rim of hydrotheca not everted. Gonophores: female gonotheca kidney-shaped, with 2 fused hydrothecae in the middle of concave side, larvae develop inside gonotheca, male gonotheca ovoid, elongated, with a terminal aperture.

Cnidome. Microbasic and macrobasic mastigophores.

Habitat type. Shallow-moderately deep waters (0–150 m) ( Boero & Fresi, 1986; Schuchert 2005b).

Substrate. Dorocidaris (Echinodermata) , algae, rock, concretions, barnacles, hydroids.

Seasonality. February ( Stechow 1919; De Vito 2006; this study); April–December ( Boero & Fresi 1986); February, June (Puce et al. 2009); January (C. Gravili unpublished observations) in the Mediterranean Sea.

Reproductive period. June, November–December ( Boero & Fresi 1986), and June (Puce et al. 2009) in the Ligurian Sea.

Distribution. Nearly cosmopolitan ( Kramp 1935; Naumov 1969 in part; Medel & López-González 1996; Medel & Vervoort 2000; Schuchert 2001a (in part), 2005b; Bouillon et al. 2004; Gravili et al. 2008a).

Records in Salento. Rare at Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; this study).

Remarks. A cold water species that is apparently becoming rarer than in the past.

References. Motz-Kossowska (1911), Leloup (1934), Stechow (1919), Picard (1958a), Rossi (1971), Marinopoulos (1981), Boero (1985), Boero & Fresi (1986), Gili (1986), Llobet et al. (1986, 1991), Llobet i Nadal (1987), Medel & López-González (1996), Medel et al. (1998), Medel & Vervoort (2000), Bouillon et al. (2004), Schuchert (2005b), De Vito (2006), Gravili (2006), Gravili et al. (2008a), Morri et al. (2009), Puce et al. (2009).

Figures

FIGURE 61. Halecium beanii: A, colony; B, branches and gonothecae; C, female gonotheca with developing embryos; D, male gonotheca (C, D same scale bar) (redrawn and modified: A after Cornelius 1995, B after Millard 1975 by A. Gennari; C, D after Schuchert 2005 by C. G. Di Camillo). Scale bars: A, 1.0 cm; B, C, D, 0.5 mm.