Aglaophenia harpago

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 : 75-76

Aglaophenia harpago von Schenck, 1965

Fig. 51 A–C

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

Material examined. HCUS-S 0 57 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

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

Hydroid. Hydrorhizae growing along seagrass blades; colonies erect; hydrocauli monosiphonic, up to 18 mm high, bending backwards, one prosegment basally separated by a hinge joint which allows bending in response to current surge, remaining parts of the axis composed of segments bearing one pseudonematotheca and 3 guttershaped nematothecae, nodes slightly oblique, intermediate segments with frontal nematothecae occur distally in some stems between hydrocladia-bearing segments, caulus ended by thick, narrow hook, occurring especially in spring and summer, coenosarc of the colony with zooxanthellae; hydrocladia more spaced than in other Aglaophenia species, cormidia with one hydrotheca and 3 nematothecae; hydrothecae may vary from long and narrow in some colonies to wider and shorter in other ones (length/breadth ratio: 1.5–2.0); corbulae short, with 4–6 pairs of ribs fused in female, partly open in male, colonies dioecious. Colours: hydrocauli, hydrocladia and corbulae brown.

Cnidome. Microbasic mastigophores.

Habitat type. Depth range: 3–40 m, but at deeper zones only in clear water ( Boero & Fresi 1986; Svoboda & Cornelius 1991).

Substrate. Posidonia and Cymodocea leaves.

Seasonality. In the Ligurian Sea, from January to December ( Boero & Fresi 1986), May, September ( Giovannetti et al. 2010); in Salento waters from May to June (this study).

Reproductive period. In the Ligurian Sea, fertile colonies from June to September ( Boero & Fresi 1986); in Salento waters (this study) in May.

Distribution. Endemic to Mediterranean ( Picard 1955 as A. pluma ; Svoboda 1979; Boero & Fresi 1986; Morri et al. 1991; Svoboda & Cornelius 1991; Bianchi et al. 1993b; Medel & López-González 1996; Piraino et al. 1999; Bouillon et al. 2004; Gravili et al. 2008a; Soto Ãngel & Peña Cantero 2013).

Records in Salento. Moderately frequent at Otranto (Gravili 2006; Gravili et al. 2008a).

Remarks. This species has a method of vegetative propagation peculiar among known species of the genus; hooked terminal portions of cormoids become fastened around the leaves of adjacent plants (von Schenck 1963). Like Aglaophenia tubiformis this species always harbours, in all endodermal tissues, the symbiotic zooxanthella Symbiodinium microadriaticum in densities similar to those reported in A. tubiformis (for more details see Svoboda & Cornelius 1991).

References: Müller-Calé and Krüger (1913) as A. helleri ; Stechow (1919) as A. adriatica ; Broch (1933) as A. pluma f. gracillima, in part; Riedl (1959), Von Schenck (1963, 1965); Relini et al. (1977) and Repetto et al. (1977) both as A. pluma ; Balduzzi et al. (1979), Svoboda (1979), Boero (1981a, b), Fresi et al. (1982), Boero et al. (1985), Boero & Fresi (1986), Gili (1986), Roca (1986), García-Rubies (1987), Roca (1987), Piraino & Morri (1990), Hughes et al. (1991), Morri et al. (1991), Roca et al. (1991), Svoboda & Cornelius (1991), García-Raso et al. (1992), Bianchi et al. (1993b), Medel & López-González (1996), Piraino et al. (1999), Bouillon et al. (2004), Gravili (2006), Gravili et al. (2008a), Giovannetti et al. (2010), Moura (2011).

Figures

FIGURE 51. Aglaophenia harpago: A, colony; B, hydrotheca and associated nematothecae; C, corbula (drawn by C. G. Di Camillo). Scale bars: A, 10 mm; B, 0.5 mm; C, 1.0 mm.