Halocoryne epizoica Hadzi, 1917

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 : 67-69

Halocoryne epizoica Hadzi, 1917

Fig. 46 A–F

See Schuchert (2010) for a complete synonymy.

Material examined. HCUS-S 0 51 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp stage.

Description (based on our own observations; Hadzi 1917a, b; Brinckmann-Voss 1970; Bouillon 1974; Piraino et al. 1992; Schuchert 2010):

Hydroid. Hydrorhiza reticular, embedded in bryozoan colonies; colonies stolonal, polymorphic; gastrozooids cylindrical, very thin, sessile, naked, lacking tentacles but with 2 prominent ectodermal swellings containing stenoteles on opposite sides of the mouth; dactylo-gonozooids stouter than gastrozooids, without mouth and tentacles, with a terminal spherical cnidocyst cluster and up to 5 additional cnidocyst clusters along one side of the body or arranged in an interrupted spiral towards hydrorhiza. Colours: gonozooids dark red, other polyps dark red to transparent.

Eumedusoid: liberated or not, borne singly or in clusters on short pedicels on lower part of dactylogonozooids, bell-shaped with 4 exumbrellar cnidocyst pouches connected with marginal bulbs, manubrium reaching two thirds the height of subumbrellar cavity, without mouth; 4 radial canals; gonads completely encircling manubrium; 4 perradial marginal bulbs, without tentacles. Colours: dark red due to dense granules identical to those of the dactylo-gonozooids.

Habitat type and substrate. Polyps grow in association with the bryozoan Schizoporella sanguinea (depth range: 0–40 m, also up to 100 m) ( Hadzi 1917a, b; Piraino et al. 1992; this study).

Seasonality. From January to December in Salento waters (De Vito 2006; this study).

Reproductive period. Fertile colonies occur in April, June–October (De Vito 2006; this study) in Salento waters.

Cnidome. Stenoteles of two sizes (polyp); stenoteles of two sizes, macrobasic euryteles (?), and macrobasic mastigophores (medusa).

Distribution. Endemic to the Mediterranean Sea ( Brinckmann-Voss 1970; Piraino et al. 1992; Bouillon et al. 2004; Gravili et al. 2008a; Schuchert 2010).

Records in Salento. Common in the following localities: Torre dell’Inserraglio, Montagna Spaccata, La Strea, La Rotonda, Porto Badisco, Marina di Corsano, Palude del Capitano, Torre Vado, Ponte del Ciolo ( Presicce 1991); Ionian and Adriatic coasts of Apulia ( Piraino et al. 1992); Porto Cesareo (Boero et al. 2000); Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; this study).

Remarks. The whole life cycle was examined in the present study. Halocoryne epizoica engulfs and feeds on the lophophoral tentacles of its bryozoan host Schizobrachiella sanguinea ( Piraino et al. 1992) .

References. Hadzi (1917), Picard (1958a), Brinckmann-Voss (1970), Petersen (1990), Piraino et al. (1992, 1999), Boero et al. (2000), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Gravili et al. (2008a), Schuchert (2010).

Figures

FIGURE 46. Halocoryne epizoica: A, general aspect of fertile colony; B, partly spent male eumedusoid; C, particular of a marginal bulb with a nematocyst patch; D undischarged macrobasic eurytele (?); E, F, discharged and undischarged macrobasic mastigophores (D, E, and F same scale bar) (modified after Piraino et al. 1992). Scale bars: A, 1.0 mm; B, 0.5 mm; C, 0.1 mm; D, E, F, 10.0 µm.