Synonyms: (basyonim) Spongites dentata Kützing (1841) p. 33; Melobesia dentata (Kützing) Decaisne (1842) p. 126; Melobesia agariciformis Areschoug (1851) da J. Agardh p. 516; Lithothamnium dentatum (Kützing) Areschoug (1852) p. 525; Lithophyllum incrustans f. dentata (Kützing) Heydrich (1901) p. 190.

VEGETATIVE FEATURES

Thallus habit: encrusting, with thin vertical lamellae having the same height, forming cushion-like thalli or subspherical free-living specimens. Thin, brittle, margin often missing; undulate, sometimes dentate edge. Size: diameter up to 20cm (protuberances 1.3cm in diameter), 1mm thick. Colour of living specimen: from white to mauve grey. Colour of dried specimen: from pink to violet.

Basal filaments: unilayered, very thin cell walls: 20-36 (42)µm long x 6-l0µm in diameter. Erect filaments: multilayered (A), loosely aggregated, cells: (4) 7-16 (20)µm long x (6) 9 (11)µm in diameter. Epithallial cells: single, rounded to elliptical (B): 3-6µm long x 7-11µm in diameter. Cell connections: secondary pit-connections.

Gametangial conceptacles: carpogonial outer diameter 250-350µm. Tetra/bisporangial conceptacles: uniporate (C), immersed (D); 130-230µm in diameter x 100-120µm high, columella remnants (D). Phenology: ---

Habitat: occurring in exposed to waves action or with strong currents areas (free-living forms). This species often lives in association with Lithophyllum byssoides, with which it may be confused; together they form “trottoirs”. Reported also as epiphyte on Cystoseira species together with Lithophyllum incrustans. Bathymetric distribution: midlittoral and upper sublittoral. Geographic distribution (Babbini & Bressan 1997):

Alboran Sea (A): Spain, Morocco; Western Mediterranean Sea (African shores) (B): Algeria, Tunisia; Middle Western Mediterranean Sea (C): Spain, Italy; North Western Mediterranean Sea (D): Spain, France; Middle Adriatic Sea (F): Italy, Croatia; South Adriatic Sea (G): Italy, Albania; South Eastern Mediterranean Sea (H): Italy, Malta; Middle Eastern Mediterranean Sea (L): Greece; North Eastern Mediterranean Sea (M): Greece.