The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide Author Gravili, Cinzia Author Vito, Doris De Author Camillo, Cristina Gioia Di Author Martell, Luis Author Piraino, Stefano Author Boero, Ferdinando text Zootaxa 2015 3908 1 1 187 journal article 42365 10.11646/zootaxa.3908.1.1 6f1d1977-6b97-4789-828c-76ed250cf1ae 1175-5326 242729 D6AD2B49-170B-4D9C-84AA-DBE0FEEAD8BE Eleutheria dichotoma Quatrefages, 1842 Fig. 33 A, B See Schuchert (2006) for a complete synonymy. Material examined. HCUS-S 038p and HCUS-S 038m (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp and medusa stages. Description (based on our own observations; Brinckmann-Voss 1970 ; Schuchert 2006, 2012): Hydroid. Colonies stolonal, small; hydrorhiza as creeping, unbranched or slightly branched tubes, covered by smooth and delicate perisarc extending to base of hydranth; hydrocaulus absent or rudimentary; hydranth cylindrical, very extensile; hypostome large, rounded-conical, with glandular perioral cavity at apex; with up to 10 capitate oral tentacles in one whorl; medusae buds in lowest part of hydranth, either singly or in clusters borne on short branching, or not, gonostyle, carrying up to four medusa buds. Colours: hydranth with pink or white gastrodermis, depending on food. Medusa. Adult. Umbrella flatter than hemispherical, 0.3 mm high, 0.5 mm wide; manubrium cylindrical to conical, extending slightly beyond umbrella margin; usually 6 radial canals; gonads in specialized umbrellar brood pouches situated above manubrium; with a thick marginal cnidocyst ring; up to 14 solid marginal tentacles, usually 5–6, not corresponding to the radial canals, bifurcated in lower, unarmed, branch with an adhesive disk and upper branch with a single cnidocyst knob; with one abaxial ocellus on each tentacular base; medusa buds on exumbrellar side of circular canal. Colours: body olive-cream, ocelli red to brown. Developmental stages. Detailed descriptions are reported by Schierwater (1989) . FIGURE 33. Eleutheria dichotoma : A , hydranths developing medusa buds; B , medusa with buds (drawn by C.G. Di Camillo). Scale bars: A, 1.0 mm; B, 0.5 mm. Cnidome. Stenoteles of two size classes (polyp); stenoteles and desmonemes (medusa). Habitat type . Medusa frequents small rocky pools in the tidal regions on weeds (depth range: 0–20 m ) (see Schuchert 2006). Substrate. Preferably on Ulva , but also Gigartina and Cystoseira (algae), Posidonia leaves. Seasonality. In the Mediterranean Sea, Eleutheria dichotoma occurs from March to October (for a review see Bouillon et al. 2004). Reproductive period. In the Tyrrhenian Sea, fertile colonies occur from February to March (Brinckmann- Voss 1970 ); along the Mediterranean French coast in August ( Galea 2007 ). Distribution. Atlantic, Pacific, Mediterranean, Black Sea ( Thiel 1935 ; Kramp & Damas 1925 ; Teissier 1965 ; Medel & López-González 1996 ; Brinckmann-Voss 1970 ; Bouillon et al. 2004; Fraser et al. 2006 ; Schuchert 2006; Gravili et al. 2008a ). Records in Salento. Rare at: Porto Cesareo, S.ta Caterina, Costa Merlata (Ionian and Adriatic Apulian coast), ( Miglietta et al . 2000 ; Gravili 2006; Gravili et al. 2008a ). Remarks. The whole life cycle was examined in the present study. The polyp has been found in nature a few times (see Schuchert 2006). Eleutheria dichotoma medusae are a favourite subject for numerous studies due to easy rearing ( Hartlaub 1886 ; Lengerich 1923a , b ). References. Lo Bianco (1909) , Mayer (1910) , Russell (1953) , Picard (1958a) , Kramp (1959 , 1961 ), Rossi (1971) , Medel & López-González (1996) , Miglietta et al. (2000) , Bouillon et al. (2004), Gravili (2006), Schuchert (2006, 2012), Galea (2007) , Gravili et al. (2008a) .