Clytia noliformis McCrady 1859

Clytia noliformis (McCrady, 1859)

Fig. 104 A, B

See Calder (1991) for a complete synonymy.

Material examined. HCUS-S 111 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp stage.

Description (after Calder 1991; Lindner & Migotto 2002):

Hydroid. Hydrorhiza as creeping stolons; colonies stolonal; pedicel strongly annulated basally and distally; hydranth with about 25–30 filiform tentacles; hydrothecae campanulate, thick diaphragm, basal chamber shallow, subspherical, margin with about 13–15 blunt, broadly triangular teeth. Colours: hydranth and coenosarc yellowish. Gonothecae laterally flattened, arising from hydrorhiza, on short annulated stalks.

Habitat type. Posidonia (Boero 1981a, b); on eupelagic Sargassum in the open North Atlantic Ocean (Calder 1991).

Substrate. Algae, Posidonia leaves and rhizomes, mussels, and hydroids.

Medusa. Adult. Umbrella flatter than a hemisphere, 6 mm wide, 3 mm high; manubrium tubular; mouth quadrate, with 4 simple lips; 4 radial canals; gonads elongated, on the distal third or fourth of the radial canals, female gonads bearing 20–35 large ova; 16 marginal tentacles; 16 intervening statocysts. Colours: bell transparent; gonads, manubrium, bulbs and tentacles assuming the colour of food.

Developmental stages. Newly released medusa with hemispherical umbrella; manubrium 0.4 height of umbrella; mouth quadrate, with 4 smooth lips; 4 perradial canals and one circular canal; velum broad; gonads absent; 4 perradial marginal tentacular bulbs and 2 or 4 interradial secondary atentacular bulbs usually present; 4 hollow tentacles, with a terminal nematocyst cluster; 8 adradial statocysts, each with one statolith.

Cnidome. A-type microbasic mastigophores and merotrichous isorhizas (polyp); A-, C-, and D-type microbasic mastigophores and holotrichous isorhizas (medusa) (nematocyst nomenclature follows that of Östman, 1979a, b).

Seasonality. January (Puce et al. 2009), April, August (Boero & Fresi 1986), June (Llobet i Nadal 1987), and July (Llobet et al. 1991) in the western Mediterranean; October, February (Faucci & Boero 2000) in Salento waters; January–May, July–December (for a review see Bouillon et al. 2004).

Reproductive period. January (Puce et al. 2009), and August (Boero & Fresi 1986) in the Ligurian Sea.

Distribution. Atlantic, Indo-Pacific, Mediterranean (Medel & López-González 1996; Morri & Bianchi 1999; Morri et al. 1999; Lindner & Migotto 2002; Bouillon et al. 2004; Gravili et al. 2008a; Puce et al. 2009; Soto Ãngel & Peña Cantero 2013).

Records in Salento. Rare at: La Strea, Porto Cesareo (Faucci & Boero 2000; Ventura 2011); Otranto (Gravili 2006; Gravili et al. 2008a; Ventura 2011).

Remarks. Only the hydroid stage was seen in the present study. Lindner and Migotto (2002) stressed the importance of the knowledge of life cycle and cnidome for species identification, especially for the confused C. noliformis synonymy. The newly liberated medusa of C. noliformis, indeed, differs from corresponding stages of C. hemiphaerica by the complete absence of gonads.

References. Stechow (1919), Picard (1949), Brian & Pérès (1954), Vannucci & Ribeiro (1955), Boero (1981a, b, c), Boero & Fresi (1986), Gili (1986), Llobet et al. (1986, 1991), Calder (1991), Medel & López- González (1996), Morri & Bianchi (1999), Morri et al. (1999), Piraino et al. (1999), Faucci & Boero (2000), Lindner & Migotto (2002), Bouillon et al. (2004), Gravili (2006), Gravili et al. (2008a), Puce et al. (2009), Bianchi et al. (2011), Ventura (2011), Calder (2013).