Aglaophenia elongata Meneghini, 1845

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 : 74-75

Aglaophenia elongata Meneghini, 1845

Fig. 50 A, B

See Svoboda & Cornelius (1991) for a complete synonymy.

Material examined. HCUS-S 0 56 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Svoboda 1979; Svoboda & Cornelius 1991):

Hydroid. Hydrorhiza as short stolons, branching only occasionally; colonies erect, bushy; hydrocauli monosiphonic, up to 300 mm high, closely grouped, axis basally with 1–4 prosegments with oblique nodes, remainder internodes each bearing 3 nematothecae and one abortive hydrothecae (pseudonematothecae), nodes indistinct, branching pattern of hydrocaulus include pinnate branches arising between mesial, proximal nematothecae and cladium or corbula and having 1–3 prosegments basally, ramus and cladium of same internode aligned parallel with each other up to 4th order of branching; hydrocladia alternate, spaced on stem, cormidia with one hydrothecae and three gutter-shaped nematothecae; very large, with usually long tentacles; hydrotheca narrow and deep, length/breadth ratio: 1.7–2.5, rim with 9 uniform cusps; hydranth mesial nematotheca adnate, reaching 1/ 3–1/2 of the hydrotheca, free end short, lateral nematothecae slightly above hydrothecal rim; corbulae short, with 4–6 pairs of ribs fused in female, with slits in male, free costa absent, colonies dioecious. Colours: axis brownish, hydrocladia yellow, corbulae yellowish to white.

Cnidome. Basitrichous isorhizas, microbasic mastigophores.

Habitat type. Shelf species, usually reported from 10 to 75 m depth in moderate currents ( Boero & Fresi 1986; Svoboda & Cornelius 1991; Peña Cantero & García Carrascosa 2002).

Substrate. Shells, dead bryozoans and calcareous red algae, seldom on gravelly and slightly muddy sand.

Seasonality. From January to December ( Boero & Fresi 1986) In the Ligurian Sea; from March to August, and from November to December (De Vito 2006; Piraino et al. 2013; this study) in Salento waters.

Reproductive period. In the western Mediterranean Sea, in August ( Boero & Fresi 1986), April (Gili 1986); from June to November in Salento waters (De Vito 2006; this study).

Distribution. Widely reported around the world but records outside Mediterranean seem erroneous (see Svoboda & Cornelius 1991).

Records in Salento. Moderately frequent at Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; Piraino et al. 2013; this study).

Remarks. The hydranths of this species are characterized by big and unusually long tentacles. In addition, this species seems unique in its special mode of branching; its rami are identical in structure with complete cormoids and basal segments are without hydrothecae (see Svoboda & Cornelius 1991).

References. Broch (1933), Stechow (1923), Picard (1958a), Riedl (1959, 1991), Svoboda (1979), García- Carrascosa (1981), Marinopoulos (1981), Gili & Castelló (1985), Gili & García-Rubies (1985), Boero & Fresi (1986), Gili (1986), García-Carrascosa et al. (1987), Gili et al. (1987), Svoboda & Cornelius (1991), Medel & López-González (1996), Morri & Bianchi (1999), Morri et al. (1999, 2009), Piraino et al. (1999), Peña Cantero & García Carrascosa (2002), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Gravili et al. (2008a), Bianchi et al. (2011), Piraino et al. (2013), Soto Ãngel & Peña Cantero (2013).

Figures

FIGURE 50. Aglaophenia elongata: A, general view of a colony; B, fragment of hydrocladia showing hydrothecae and associated nematothecae (drawn by L. Basso). Scale bars: A, 2.0 mm; B, 1.0 mm.