Gongolaria montagnei var. compressa (Ercegovic) Verlaque, Blanfune, Boudouresque & Thibaut

Fig. 18A-C

Cystoseira adriatica subsp. compressa Ercegovic. Basionym.

Cystoseira adriatica subsp. compressa Ercegovic, Cystoseira platyramosa Ercegovic, Cystoseira adriatica subsp. intermedia Ercegovic, Cystoseira adriatica var. intermedia (Ercegovic) Giaccone, Cystoseira spinosa var. compressa (Ercegovic) Cormaci, G. Furnari, Giaccone, Scammacca & D. Serio, Cystoseira montagnei var. compressa (Ercegovic) M. Verlaque, Blanfuné, Boudouresque, Thibaut & Sellam. Synonyms.

Morphology of specimens from Pantelleria.

This form is non-caespitose, adhering to the substrate by a discoid holdfast. The axis is trunk-like, simple, and usually shorter than in the autonymous form. All branches are flattened, with an alternate arrangement. They have serrated edges and a midrib. Spinose appendages can be present in the apical parts of secondary branches. The tophules are borne near the base of the axis, oblong and spinose. During the monitoring activities, this form was not found fertile.

Habitat.

G. montagnei var. compressa was observed during scuba dives at Punta Spadillo, Cala Levante and Cala Tramontana. In these sites, it grows in the lower infralittoral/circalittoral (from ca. 26 to 35 m of depth), on bottoms largely covered by detritus and subject to unidirectional currents.

Distribution.

G. montagnei var. compressa is known from Spain, France, Italy, Adriatic, Greece, Libya and Turkey ( Blanfuné et al. 2022).

Remarks.

This seaweed was reported by Alongi et al. (2004) with a very limited coverage at Cala Levante. Therefore, it might currently be in a phase of increase.