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 ( 1933 a, 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 ( 1958 a as A. dichotoma and A. pluma ), Riedl ( 1970, 1991), Chimenz Gusso & Rivosecchi Taramelli ( 1975), Svoboda ( 1979), Morri ( 1981 a), 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. ( 2008 a).

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.