Antennella siliquosa (Hincks, 1877)

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 : 100-101

Antennella siliquosa (Hincks, 1877)

Fig. 70 A–D

See Schuchert (1997) for a complete synonymy.

Material examined. HCUS-S 0 77 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Schuchert 1997):

Hydroid. Hydrorhiza as ramified stolons; colonies erect; hydrocladia unbranched, up to 45 mm high, basal part of the axis divided on a variable number of segments bearing frontal nematothecae by means of transverse nodes, remaining parts heteromerously segmented, with nodes alternatively oblique and transverse, hydrothecate segments with one hydrotheca and 3 nematothecae, one median inferior, and 2 lateral ones, non-hydrothecate segments bearing 2 median nematothecae; hydrotheca cylindrical, walls almost parallel, slightly divergent distally, 1/2 adnate, rim even, aperture at 35º–45º from the main axis; nematothecae all two-chambered, aperture with embayment, median nematothecae all similar, but median inferior to the hydrotheca wider, this one not reaching the level of the hydrotheca, lateral nematothecae borne on pedicels, not reaching the hydrothecal margin, basal chamber longer and elongated if compared with the rest, distal chamber typically globose, with a deep emargination on inner and outer side. Gonothecae of both sexes occurring on the same axis, borne on pedicels with 2 segments, female ones elongate, somewhat flattened, truncated distally and curved basally, with up to 4 nematothecae, male ones shorter, pyriform, extremely rounded, with 2 basal nematothecae, both with apical flat lid. Colour: whitish coenosarc.

Cnidome. Microbasic mastigophores.

Habitat type. Generally in littoral and infralittoral zones, but also as deep as 144 m (see Ramil & Vervoort 1992).

Substrate. Algae, rock, hydroids, bryozoans, Cirripedia, Ascidia, Gorgonaria, worm tubes, sponges.

Seasonality. May–October (for a review see Bouillon et al. 2004) in the Mediterranean Sea; just from February to August (De Vito 2006; this study) in Salento waters.

Reproductive period. May, July, September, October ( Schuchert 1997; Bouillon et al. 2004); August (De Vito 2006; this study).

Distribution. Mediterranean Sea, eastern Atlantic ( England, France, Strait of Gibraltar, Morocco, Ivory Coast) (Ramil & Vervoort 1992; Medel & Vervoort 1995; Medel & López-González 1996; Schuchert 1997; Ansín Agís et al. 2001; Bouillon et al. 2004; Gravili e t al. 2008a).

Records in Salento. Moderately frequent in the following localities: Torre dell'Inserraglio, S.ta Caterina ( Presicce 1991); Otranto (De Vito 2006; Gravili 2006; Gravili e t al. 2008a; this study).

Remarks. For further discussion and characters to distinguish A. siliquosa from similar species see Schuchert (1997).

References. Stechow (1919, 1923), Broch (1933) as A. diaphana f. siliquosa ; Picard (1958a) as Polyplumaria siliquosa ; Riedl (1959, 1966), Rossi (1961), García Corrales et al. (1978), Ramil & Vervoort (1992) both as Halopteris diaphana f. siliquosa ; Rossi (1961), Medel & Vervoort (1995), Medel & López-González (1996), Schuchert (1997), Piraino et al. (1999), Ansín Agís et al. (2001), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Gravili e t al. (2008a).

Figures

FIGURE 70. Antennella siliquosa: A, part of fertile colony; B, hydrocladium; C, details of nematothecae; D, left, female gonotheca; right, male gonotheca (A, D redrawn and modified after Schuchert 1997 by C. G. Di Camillo; B, C drawn by L. Basso). Scale bars: A, 1.0 mm; B, 0.5 mm; D, 0.2 mm.