Orthopyxis crenata Hartlaub 1901

Orthopyxis crenata (Hartlaub, 1901)

Fig. 112 A–D

See Peña Cantero & Carrascosa (2002) for a complete synonymy.

Material examined. HCUS-S 119 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula). Description (based on our own observations; Garcia Corrales et al. 1978 as Campanularia crenata; Peña Cantero & Carrascosa 2002):

Hydroid. Hydrorhiza as creeping stolon system; colonies stolonal; hydranth pedicels unbranched, bearing a single distal hydrotheca, with sub-hydrothecal spherule, with thickened and, usually, undulated perisarc; hydranth with about 14 tentacles; hydrotheca bell-shaped, walls thickened to a varying extent, ring of perisarc basally separating a small spherical chamber, rim with 8–13 short rounded cusps varied from deep and distinct to very shallow. Gonothecae sac-shaped, truncate distally, strongly compressed laterally, perisarc irregularly undulated, borne on hydrorhiza, on short pedicels, containing 2 eumedusoids buds.

Eumedusoid. Umbrella pyriform, up to 1.5 mm high, thin walls, exumbrella with 30–40 longitudinal meridional ridges; without manubrium; 4 radial canals closed and obliterated near apex, giving rise to numerous blindly ending side branches; circular canal narrow; gonads developed between branches of radial canals, bell cavity almost filled with sexual products; no marginal tentacles; 8 adradial statocysts.

Habitat type. Littoral species that in the Mediterranean has been reported from near the tidal level to 25 m depth (García Carrascosa 1981; Boero & Fresi 1986; Gili 1986).

Substrate. It is exclusively epibiontic and has frequently been reported on algae, phanerogams, bryozoans, sponges, hydrozoans, ascidians, and artificial substrata.

Seasonality. April–September (Boero & Fresi 1986), and March–December (Llobet et al. 1991; Puce et al. 2009) in the western Mediterranean; April–October (De Vito 2006; this study) in Salento waters.

Reproductive period. March (Stechow 1919; Gili 1986), and October–December (Llobet et al. 1991) in the western Mediterranean; October (De Vito 2006; this study) in Salento waters.

Cnidome. Microbasic mastigophores.

Distribution. Circumtropical (Millard & Bouillon 1973; Medel & López-González 1996; Peña Cantero & Carrascosa 2002; Bouillon et al. 2004; Gravili et al. 2008a; Soto Ãngel & Peña Cantero 2013).

Records in Salento. Moderately frequent in Salento waters: La Strea, Porto Cesareo (Faucci & Boero 2000; Andreano 2007); Torre dell’Inserraglio, S.ta Caterina, Costa Merlata (Andreano 2007); Grotta del Ciolo (Moscatello & Belmonte 2007); Otranto (De Vito 2006; Gravili 2006; Andreano 2007; Gravili et al. 2008a; Ventura 2011; this study).

Remarks. Cornelius (1982) suggested that O. everta could be synonymous with O. crenata.

References. Stechow (1919) as Campanularia (?) intermedia, Picard (1952), Millard (1975), García Corrales et al. (1978) as Campanularia crenata, C. delicata, and Campanularia (Orthopyxis) everta; Marinopoulos (1979); Boero (1981a, b, c) as Campanularia everta; García Carrascosa (1981), Isasi (1985), Boero & Fresi (1986) as Campanularia everta; Gili (1986); Llobet et al. (1986) and Llobet i Nidal (1987) as C. everta; Roca (1986), Ramil (1988), Llobet et al. (1991) as O. crenata but also as C. everta, Altuna (1994), Medel & López-González (1996), Piraino et al. (1999) as C. everta; Faucci & Boero (2000), Medel & Vervoort (2000), Peña Cantero & Carrascosa (2002), Bouillon et al. (2004); De Vito (2006), Gravili (2006); Moscatello & Belmonte (2007) as C. everta; Gravili et al. (2008a); Puce et al. (2009), Ventura (2011).