Ectopleura wrighti Petersen, 1979

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 : 62-63

Ectopleura wrighti Petersen, 1979

Fig. 42 A, B

See Schuchert (2010) for a complete synonymy.

Material examined. HCUS-S 0 47 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp stage.

Description (based on our own observations; Brinckmann-Voss 1970; Petersen 1990; Schuchert 2010, 2012):

Hydroid. Hydrorhiza as creeping stolons not clearly demarcated from hydrocauli; colonies small; hydrocaulus slender, unbranched, of equal width throughout, inner lumen divided into two longitudinal canals by two endodermal ridges formed by highly vacuolated cells, perisarc flexible, thin and smooth, covering hydrocauli and stolons; hydranth vasiform, very slender, having long and slender neck region with low ring-shaped collar forming a groove secreting a thin outer perisarc; one oral whorl of 4–10 slightly capitate or moniliform tentacles which are not adnate to hypostome; one aboral whorl of 8–20 filiform tentacles. Gonophores released as free medusae, developing immediately distal to aboral whorl of tentacles on one circle of up to 8 short, branched or unbranched, blastostyles. Colours: whitish to colourless, transparent.

Habitat type. The polyp occurs in the rocky littoral (depths of 0.5– 40 m) on several hard substrata and organisms ( Brinckmann-Voss 1970; Boero & Fresi 1986; Peña Cantero & García Carrascosa 2002).

Substrate. Stylocidaris (Echinodermata) , Posidonia roots and pieces of rock, algae, sponges, hydroids, barnacles, concretions.

Seasonality. In the western Mediterranean Sea, Ectopleura wrighti occurs from June to December ( Boero & Fresi 1986), October ( Galea 2007), January (Puce et al. 2009); January, March, June, September (De Vito 2006; this study), and November ( Piraino et al. 2013) in Salento waters.

Reproductive period. In the Ligurian Sea, fertile colonies occur in June ( Boero & Fresi 1986); September (this study).

Medusa. Adult. Umbrella nearly hemispherical; with four longitudinal meridian pairs of cnidocysts tracks; manubrium nearly as long as subumbrellar cavity; gonads completely encircling manubrium; with 4 perradial marginal bulbs; 2 opposite marginal perradial tentacles with a terminal knob of cnidocysts and distally 1 or 2 spherical cnidocysts knobs encircling tentacle, proximally one abaxial cnidocysts cluster.

Developmental stages. Newly released medusa spherical, exumbrella with 8 meridional lines of stenoteles; manubrium tubular, short; with 4 radial canals; gonads not developed; 4 equal bulbs of which only one opposite pair bears short tentacles, tentacles with one spherical terminal and one subterminal clasping nematocyst cluster. Colourless.

Cnidome. Stenoteles of different size classes, desmonemes, almond-shaped microbasic mastigophores, discharged shaft sometimes slightly swollen and then approaching eurytele condition (polyp); stenoteles, desmonemes, and mastigophores (medusa).

Distribution. Atlantic, Mediterranean ( Allman 1872; Stechow 1923; Wright 1963; Brinckmann-Voss 1970; Boero & Fresi 1986; Bouillon et al. 2004; Gravili et al. 2008a; Schuchert 2010).

Records in Salento. Rare at: La Strea, Porto Cesareo ( Presicce 1991; Faucci & Boero 2000; this study); S.ta Caterina ( Miglietta et al. 2000); Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; Piraino et al. 2013; this study).

Remarks. The Mediterranean records of Ectopleura minerva ( Goy 1973; Goy et al. 1991) are most probably attributable to E. wrighti (see for details Schuchert 2010). Only the hydroid stage and the new born medusa were seen in the present study.

References. Graeffe (1884), Neppi & Stiasny (1913) as E. dumortieri (see for details Schuchert 2010); Motz- Kossowska (1905), Stechow (1923), Picard (1951a, 1958a) as Acharadria larynx ; Riedl (1959), Brinckmann-Voss (1970, 1987) as Tubularia larynx ; Petersen (1979, 1990), Boero (1981a), Boero & Fresi (1986), Franzen & Hündgen (1986), Faucci & Boero (2000), Miglietta et al. (2000), Peña Cantero & García Carrascosa (2002), Bouillon et al. (2004), De Vito (2006) Gravili (2006), Galea (2007), Gravili et al. (2008a), Puce et al. (2009), Schuchert (2010, 2012), Piraino et al. (2013) as E. larynx .

Figures

FIGURE 42. Ectopleura wrighti: A, hydroids without and with blastostyles; B, medusa (drawn by F. Boero). Scale bars: A, 2.0 mm; B, 0.25 mm.