Aglaophenia pluma (Linnaeus, 1758)

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 : 81-82

Aglaophenia pluma (Linnaeus, 1758)

Fig. 55 A–D

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

Material examined. HCUS-S 0 62 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (after Svoboda 1979; Svoboda & Cornelius 1991):

Hydroid. Hydrorhiza as frequently branching stolons or following ramification of substrate alga; colonies erect; hydrocauli monosiphonic, up to 150 mm, unbranched or dichotomously branched, basal part of the axis without thecae, followed by 1 or 2 prosegments, remaining internodes with 3 nematothecae and a pseudonematotheca each, nodes oblique; hydrocladia alternate, with cormidia separated by transverse nodes; hydranth cylindrical, small; hypostome rounded and low, held at level of hydrothecal rim; 10 tentacles emerging from hydrothecal rim; hydrotheca deep (length/breadth at rim: 1.3–1.5), rim with 9 cusps of varied length; intrathecal adcauline septum usually well developed; median nematothecae 2/3 adnate, not reaching the margin of the hydrothecae, lateral nematothecae reaching the rim of the hydrothecae, aperture of nematothecae gutter-shaped; male and female corbulae, with free costa, male ones close, with slit like openings between the costae, female ones with fused costae and smaller slits, colonies dioecious. Colours: hydrocauli brown, cormidia whitish, hydranth transparent, male and female corbulae white.

Cnidome. Microbasic mastigophores.

Habitat type. Lower shore, deep pools and sublittoral from 0.5 to 20 m (also until to 100 m) ( Svoboda & Cornelius 1991).

Substrate. Algae, Posidonia , shells, other hydroids, crustacea, anthozoans, bryozoans, and calcareous concretions.

Seasonality and reproduction period. Almost all year in the Mediterranean Sea (Llobet i Nidal 1987; Ramil 1988; Llobet et al. 1991; Faucci & Boero 2000; Peña Cantero & García Carrascosa 2002; Galea 2007).

Distribution. Cited as a cosmopolitan species, but this needs confirmation due to identification problems. Reliably reported from Shetlands, British Islands, France, Belgium, Spain and Portugal, in the northeastern Atlantic ( Vervoort 1946; Patriti 1970; Svoboda 1979; Svoboda & Cornelius 1991; Medel & Vervoort 1995; Medel & López-González 1996; Ansín Agís et al. 2001; Peña Cantero & García Carrascosa 2002; Bouillon et al. 2004; Galea 2007).

Records in Salento. Rare in the following localities: La Rotonda ( Presicce 1991); La Strea, Porto Cesareo ( Faucci & Boero 2000).

Remarks. A. pluma , in contrast to the other Aglaophenia species, has no peculiar diagnostic characters and its distinction from some other species has not always been evident (see Svoboda & Cornelius 1991 for details). Notes about the growth of the colony were provided by Leloup (1933a, b), and on the corbula and gonophore development by Faure (1960).

References. Broch (1912, 1933) as A. dichotoma ; Stechow (1919 as A. dichotoma and A. pluma, 1923 ), Leloup (1934), Rossi (1950, 1961, 1971), Picard (1958a as A. dichotoma and A. pluma ), Riedl (1970, 1991), Chimenz Gusso & Rivosecchi Taramelli (1975), Svoboda (1979), Morri (1981a), Morri & Martini (1981), Llobet et al. (1986, 1991), Llobet i Nidal (1987), Svoboda & Cornelius (1991), Altuna (1994), Medel & Vervoort (1995), Medel & López-González (1996), Faucci & Boero (2000), Ansín Agís et al. (2001), Peña Cantero & García Carrascosa (2002), Bedini et al. (2003), Bouillon et al. (2004), Galea (2007), Gravili et al. (2008a).

Figures

FIGURE 55. Aglaophenia pluma: A, general view of a colony; B, basal part of caulus; C, detail of a hydranth (B, C same scale bar); D, corbula (drawn by C. G. Di Camillo). Scale bars: A, 10 mm; B, C, 350 µm; D, 1.0 mm.