Amphinema bouilloni Schuchert 2007

Amphinema bouilloni Schuchert, 2007

Fig. 28 A–C

See Schuchert (2007) for a complete synonymy.

Material examined. HCUS-S 0 33 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp stage; IG 27838 (see Bouillon et al. 1997)—medusa stage.

Description (based on our own observations; Boero et al. 1997b as Codonorchis octaedrus; Schuchert 2007):

Hydroid. Hydrorhiza as creeping stolons; colonies stolonal; hydranths fusiform, sessile, small, 0.25 mm, naked; hypostome short, conical; with 4–6 filiform tentacles in a single whorl; medusa buds each borne on a pedicel of variable length but generally longer than hydranth, arising from hydrorhiza. Colours: hydranth yellow, hypostome white; medusa buds orange.

Habitat type and substrate. Marine cave, on organogenic concretions; depth 25 m (Boero et al. 1997b).

Seasonality. September (Boero et al. 1997b).

Reproductive period. September (Boero et al. 1997b).

Medusa. Adult. Umbrella 2.5 mm wide, 4 mm high, with a high conical or globular apical projection; manubrium urn-shaped, with wide base, with an apical chamber, without gastric peduncle; mouth cruciform, with 4 simple recurved lips; with mesenteries; 4 broad ribbon-like radial canals with jagged edges; gonads on interradial walls of manubrium only, separated perradially, large, horse-shoe shaped, with some interradial folds; up to 16 marginal bulbs, 2 of which are conical in shape and bear one long opposite hollow marginal tentacle, the others as rudimentary bulbs with tentacle rudiments; all bulbs with ocelli.

Developmental stages. Newly released medusa higher than wide, with small apical projection, exumbrella with numerous nematocysts; manubrium tubular, reaching 1/4 of subumbrellar height; mouth quadratic with 4 small lips; 4 ribbon-like radial canals and ring canal; 4 perradial marginal bulbs, each with an ocellus, one opposite pair of bulbs larger, conical, with a short tentacle on each. Colours: manubrium orange, red ocelli.

Cnidome. Microbasic euryteles and desmonemes (hydroid and medusa).

Distribution. Mediterranean Sea near Otranto, between Adriatic and Ionian Sea (Boero et al. 1997b; Gravili et al. 2008a).

Records in Salento. Rare at Otranto (Denitto 1996; Boero et al. 1997b; Miglietta et al. 2000).

Remarks. The whole life cycle was examined in the present study. This species was originally identified as Codonorchis octaedrus by Boero et al. (1997b). Schuchert (2007) disagreed with this identification, and described it as a new species, as it lacks the crucial feature of the genus Codonorchis, the gonads that extend to the subumbrella (this feature is unique and renders the genus very distinct).

References. Boero et al. (1997b), Gravili (2006) both as Codonorchis octaedrus; Gravili et al. (2008a), Schuchert (2007).