Aglaophenia octodonta (Heller, 1868)

Fig. 53 A–C

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

Material examined. HCUS-S 0 60 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula). Description (based on our own observations; Svoboda 1979; Svoboda & Cornelius 1991):

Hydroid. Hydrorhiza as densely fused and anastomosing stolons; colonies erect; hydrocauli monosiphonic, basally with several transverse nodes and with 1–3 prosegments separated by oblique nodes, remaining parts composed of hydrocladia-bearing internodes, with 3 gutter-shaped nematothecae and a pseudonematotheca; hydrocladia closely alternate, cormidia separated by transverse nodes; hydrothecae narrowing basally, triangular, not deep (length/breadth at rim: 1.1–1.4), rim with 9 uniform cusps, adcauline septum in lower third of hydrothecal cavity well developed; median nematothecae 2/3 adnate, free end short almost reaching the hydrothecal rim, end of nematotheca usually curved outwards and reaching almost level to hydrothecal rim, lateral nematothecae small, apical part swollen, reaching hydrothecal rim; male corbula without free costae and usually partly open, female corbula usually closed, with one well developed free costa. Colours: hydrocauli yellowish to brown, hydrocladia transparent to yellowish, male corbula white, female corbula yellow.

Cnidome. Basitrichous isorhizas, microbasic mastigophores.

Habitat type. Wave-washed areas (depth range: 0–50 m) (Boero & Fresi 1986; Svoboda & Cornelius 1991).

Substrate. Algae, rock, shells of Balanus and Mytilus, sponges, colonial ascidians and, locally, on Posidonia rhizomes.

Seasonality. Throughout the year (Svoboda & Cornelius 1991; De Vito 2006; this study).

Reproductive period. In the western Mediterranean Sea from March to November (Boero & Fresi 1986), April–June (Roca 1986), March–April (Stechow 1919), August–September (Picard 1951b), May (Gili 1986); in Salento waters (De Vito 2006; this study) throughout the year.

Distribution. Northeastern Atlantic and Mediterranean (Svoboda & Cornelius 1991; Ramil & Vervoort 1992; Medel & López-González 1996; Morri & Bianchi 1999; Morri et al. 1999; Ansín Agís et al. 2001; Peña Cantero & García Carrascosa 2002; Bouillon et al. 2004; Gravili et al. 2008a; Morri et al. 2009; Puce et al. 2009; Bianchi et al. 2011; Soto Ãngel & Peña Cantero 2013).

Records in Salento. Common at: Torre dell'Inserraglio (Presicce 1991; Andreano 2007); Torre S. Emiliano, Marina di Corsano, Ponte del Ciolo, Il Chiapparo (Presicce 1991; Miglietta et al. 2000); La Strea, Porto Cesareo (Denitto 1996; Faucci & Boero 2000; Andreano 2007; Ventura 2011); Torre Lapillo, S.ta Caterina (Andreano 2007); Grotta del Ciolo (Moscatello & Belmonte 2007); Costa Merlata, Adriatic Apulian coast (Fraschetti et al. 2002; Andreano 2007); Otranto (Fraschetti et al. 2002; De Vito 2006; Gravili 2006; Andreano 2007; Gravili et al. 2008a; Stabili et al. 2008; Ventura 2011; this study).

Remarks: Aglaophenia octodonta is easy to distinguish from other species of the same genus occurring in shallow waters of the east and central Mediterranean Sea (for details see Svoboda & Cornelius 1991).

References: Stechow (1919), Picard (1958a); Riedl (1959) as A. pluma f. octodonta; Rossi (1971), Boero (1981c, 1985), García Carrascosa (1981), Boero & Fresi (1986), Roca (1986), Ramil (1988), Svoboda & Cornelius (1991), Ramil & Vervoort (1992), Medel & Vervoort (1995), Medel & López-González (1996), Ansín Agís (1998), Morri & Bianchi (1999), Piraino et al. (1999), Faucci & Boero (2000), Miglietta et al. (2000), Ansín Agís et al. (2001), Fraschetti et al. (2002), Peña Cantero & García Carrascosa (2002), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Moscatello & Belmonte (2007), Gravili et al. (2008a), Stabili et al. (2008), Morri et al. (2009), Puce et al. (2009), Bianchi et al. (2011), Ventura (2011).