Campalecium torreyi ( Motz-Kossowska, 1911 )

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 : 115-117

Campalecium torreyi ( Motz-Kossowska, 1911)

Fig. 82 A–F

See Altuna (2008) for a complete synonymy.

Material examined. HCUS-S 090p HCUS-S 090m (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp and medusa stages.

Description (based on our own observations; Altuna 1993, 2008):

Hydroid. Hydrorhiza as simple stolons; colony stolonal; hydrocaulus as hydranth pedicel of varied length bearing terminal hydranth, secondary pedicels often forming sympodial branches; hydranth elongated, cylindrical, relatively large, not retractable into hydrotheca, endodermal epithelium differentiated into distinct parts, the upper one digestive, the basal one formed by chordal cells; up to 30 amphicoronate tentacles; with intertentacular web; hydrotheca collar-shaped, shallow, often regenerated, with a distinct diaphragm, with large desmocytes. Gonothecae clavate or rounded, arising beneath hydrothecal pedicel, each with several medusa buds.

Habitat type. Rocky bottoms, Posidonia , sand and pebbles (depth range: 0–25 m) (own data; Boero & Fresi, 1986; Altuna 1993).

Substrate. Algae, hydroids, Posidonia rhizomes, barnacles, sponges, and Anthozoa.

Rearing of medusae. Released medusae (6) were divided into two groups of three individuals each: the first group was reared under the same conditions as the hydroid colony (14°C), while the second was kept at 24°C (preliminary observations showed that gonad development was faster at higher temperatures).

Medusa. When newly released, umbrella 0.8 mm wide, almost hemispherical, manubrium short, urn-shaped; mouth with 4 simple lips; 4 perradial marginal bulbs, 4 perradial marginal tentacles, without lateral cirri or marginal warts, after a few days lateral cirri appear on tentacular bulbs; with 8 statocysts.

Medusa reared at 14°C:

Five-day-old medusa. Umbrella 1.0 mm wide; 4 bulbs each flanked by one pair of lateral spiral cirri; 2 tentacles, 2 rudimental tentacles; one rudimentary marginal wart between successive tentacles; about 8 statocysts; no gonads.

Thirty-day-old medusa. Umbrella 2.0 mm wide; 8 marginal tentacles with conspicuous basal bulbs, each flanked by 3 pairs of lateral spiral cirri; usually with 3–5 rudimentary marginal warts between successive tentacles; about 12 statocysts; no gonads.

Medusa reared at 24°C:

Five-day-old-medusa. Umbrella 1.0 mm wide; 4 bulbs each flanked by one pair of lateral spiral cirri; 2 tentacles, 2 rudimental tentacles one rudimentary marginal wart between successive tentacles; about 8 statocysts; appearance of 4 rudiments of gonads on distal half of radial canals.

Thirty-day-old medusa. Umbrella 2.0 mm wide; 4 marginal tentacles with conspicuous basal bulbs, each flanked by 2 pairs of lateral spiral cirri; usually with one rudimentary marginal wart between successive tentacles; about 8 statocysts; 4 sausage-shaped gonads on distal half of radial canals.

Cnidome. Merotrichous haplonemes, microbasic mastigophores.

Seasonality. January–December ( Boero & Fresi 1986; De Vito 2006; this study) in the Mediterranean Sea.

Reproductive period. August–November ( Boero & Fresi 1986), and April–July ( Llobet i Nadal 1987) in the western Mediterranean; March, October (De Vito 2006; this study) in Salento waters.

Distribution. Atlantic, Mediterranean (Altuna 1993; Medel & López-González 1996; Calder 1991; Schuchert 2003; Bouillon et al. 2004; Gravili et al. 2008a).

Records in Salento. Rare in the following localities: S.ta Caterina, S.ta Maria al Bagno, Gulf of Taranto ( Denitto 1996; Miglietta et al. 2000); Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; Piraino et al. 2013; this study); Grotta del Ciolo (Denitto et al. 2007).

Remarks. The whole life cycle was examined in the present study. This species has often been recorded as Campalecium medusiferum Torrey, 1902 , a nominal species described from the California coast, based on the hydroid stage. As remarked by Altuna (2008) it is unlikely that the Mediterranean species is identical with the Californian one. The taxonomic situation of the various species referable to Campalecium is complicated and unresolved (see Calder 1991). Due to similarity among “ Campalecium ” hydroids, several authors regarded most of them as conspecific or questionably conspecific ( Calder 1991; Schuchert 2003). The genus Mitrocomium (as defined in Brinckmann (1959) based on Haleciella microtheca ) presents considerable problems not only at the species level, but also at the family level and is considered as synonymous with Lovenella by Bouillon et al. (2006), having companulinid hydroids, not sharing the features of the present species. Altuna (2008) assigned this species to Eucheilota , as E. medusifera? (Torrey, 1902) (comb. nov.) and considered Campalecium a likely synonym of that genus. We cannot share Altuna’s (2008) opinion of referring this nominal species to Eucheilota , since other species of this genus do have campanulinid hydroids (e.g. Eucheilota maculata Hartlaub, 1894 ) but we prefer to avoid referring it to the Californian nominal species. The oldest record of a Campalecium species in the Mediterranean is by Motz-Kossowska (1911) and, following Altuna’s (2008) suggestion, we provisionally refer this material to this nominal species. In the present study, the stages of development of the medusa at two different temperatures have been described. It is evident that environmental stimuli may, within the same species, cause a variation of the stage of development reached by a medusa by the time of its release as reported by Hincks (1868) for the species Clytia hemisphaerica .

References. Haeckel (1879) as Mitrocomium cirratum ; Mayer (1910) as Mitrocoma cirrata ; Motz-Kossowska (1911) as Halecium torreyi ; Hadzi (1914) as Haleciella microtheca ; Huvé (1954), Picard (1951a, 1958a) all as Campalecium medusiferum ; Brinckmann (1959) as Eucheilota cirrata ; Boero (1981a), Bavestrello (1985), Boero & Fresi (1986), Gili (1986), Llobet et al. (1986, 1991), Boero & Sarà (1987), Llobet i Nadal (1987), Morri et al. (1991) all as C. medusiferum ; Altuna (1993) as Mitrocomium cirratum ; Miglietta et al. (2000), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Denitto et al. (2007), Gravili et al. (2008a) all as C. medusiferum ; Altuna (2008) as Eucheilota medusifera ?; Puce et al. (2009), Piraino et al. (2013) as C. medusiferum .

Figures

FIGURE 82. Campalecium torreyi: A, hydranth and gonotheca with medusa buds; B, lateral view of juvenile medusa; C, oral view of juvenile medusa; D, intact and discharged merotrichous haplonemes; E, thirty-day-old medusa reared at 14 ° C; F, thirty-day-old medusa reared at 24 ° C (B and C same scale bar; E and F same scale bar) (A, B, C drawn by F. Boero; D, E drawn by C. G. Di Camillo; F drawn by C. Gravili). Scale bars: A, 1.0 mm; B, C, 250 µm; D, 0.1 mm; E, F, 2.0 mm.