Hydrodendron mirabile (Hincks, 1866)

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 : 97-98

Hydrodendron mirabile (Hincks, 1866)

Fig. 68 A–D

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

Material examined. HCUS-S 0 75 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula). Description (based on our own observations; Bouillon et al. 1986 as Ophiodissa mirabilis ; Peña Cantero & García Carrascosa 2002):

Hydroid. Hydrorhiza as irregularly branched stolons; colonies erect, up to 50 mm; hydrocauli monosiphonic, branched distally, with transverse nodes, lateral hydrophores, alternate, at upper part of internodes, variable in length and usually annulated, with basally thicker and progressively thinner perisarc; hydranths with 20 tentacles; hydrotheca deep, widening from halfway onward; rim everted, occasionally curved downwards; nematophores on hydrorhiza and on hydrophores, elongate, distally capitate, strongly retractile; nematothecae tubular in basal 2/3, cup-shaped distally. Gonothecae on hydrorhiza, on short pedicels, barrel-shaped spacely ringed throughout, aperture wide on a short collar.

Cnidome. Microbasic mastigophores, pseudostenoteles ( Bouillon et al. 1986).

Habitat type. Littoral, from 0.5 to 40 m depth ( García Corrales et al. 1978; Boero & Fresi 1986).

Substrate. Algae, Posidonia , barnacles, sponges, bryozoans.

Seasonality. April, June, November ( Boero & Fresi 1986) in the Ligurian Sea; February, April, June, July, October–December (for a review see Bouillon et al. 2004); January–December (De Vito 2006; this study) in Salento waters.

Reproductive period. July ( Motz-Kossowska 1911) in the western Mediterranean; August (De Vito 2006; this study) in Salento waters.

Distribution. Eastern and western Atlantic, Indo-Pacific, Mediterranean ( Cornelius 1975; Millard 1975; Medel & López-González 1996; Peña Cantero & García Carrascosa 2002; Bouillon et al. 2004; Çinar et al. 2008; Gravili et al. 2008a; Puce et al. 2009).

Records in Salento. Moderately frequent at the following localities: Torre dell’Inserraglio ( Presicce 1991; Andreano 2007); La Strea, Porto Cesareo ( Faucci & Boero 2000); Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; this study); Torre Lapillo, S.ta Caterina ( Andreano 2007); Grotta del Ciolo (Denitto et al. 2007; Moscatello & Belmonte 2007); Other Apulian records: Gargano ( Fraschetti et al. 2002).

Remarks. Cornelius (1975b) considered Ophiodes mirabilis Hincks, 1866 b as conspecific with Ophiodes caciniformis Ritchie, 1907 , the latter being based on larger colonies than those originally referred to Hincks’s species.

References. Motz-Kossowska (1911) as Ophiodes mirabilis ; Babic (1913a) as Ophiodes caciniformis ; Bedot (1914) as Ophiodes mirabilis ; Stechow (1919), Leloup (1934), Picard (1951a, 1952, 1958 a), Vervoort (1959), Boero & Fresi (1986) as Ophiodissa mirabilis ; Gili (1986); Ramil (1988) as Ophiodissa mirabilis ; Altuna (1994), Medel & López-González (1996); Piraino et al. (1999), Faucci & Boero (2000), Medel & Vervoort (2000), Fraschetti et al. (2002), Peña Cantero & García Carrascosa (2002), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Denitto et al. (2007), Moscatello & Belmonte (2007), Cinar et al. (2008), Gravili et al. (2008a), Puce et al. (2009).

Figures

FIGURE 68. Hydrodendron mirabile: A, part of colony; B, nemathoteca and nematophore with one hydrotheca; C, details of hydrotheca and nematotheca; D, nematocysts (drawn by F. Boero). Scale bars: A, 0.5 mm; B, 250 µm; C, 0.1 mm; D, 10 µm.