Orthopyxis crenata (Hartlaub, 1901)

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 : 158-159

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).

Figures

FIGURE 112. Orthopyxis crenata: A, hydroid; B, male gonotheca; C, female gonotheca; D, eumedusoid (B, C same scale bar) (redrawn and modified: A after Medel & Vervoort 2000, B, C, D after Hirohito 1995 by C. G. Di Camillo). Scale bars: A, B, C, D, 1.0 mm.