Dysidea fragilis (Montagu, 1818)

Manconi, Renata, Cadeddu, Barbara, Ledda, Fabio & Pronzato, Roberto, 2013, An overview of the Mediterranean cave-dwelling horny sponges (Porifera, Demospongiae), ZooKeys 281, pp. 1-68 : 14-15

Dysidea fragilis (Montagu, 1818) Fig. 9

Spongia fragilis Montagu, 1818: 114.

Description.

Growth form irregular, massive; usually less than 10 cm in diameter, sometimes up to 15-20 cm in diameter and 2-3 cm in height. Colour in vivo (generally also preserved specimens) light grey to white; several, slightly perceptible, tone dominances are possible (light green to light brown). Consistency soft and fragile. Surface, shared by all species of the genus, as an irregular network of dense collagen fibres, sometimes with mineral debris. Inhalant apertures 80-120 µm in diameter. Oscules scattered (2-4 mm in diameter). Light collagen amount (fibrous reticulate) in the mesohyl. Flagellate chambers large. Skeleton reticulate, with irregular meshes (300-600 µm), and extremely fragile because of scanty spongin and extreme abundance of mineral granulation. Primary and secondary fibres (40-200 µm) not distinguishable or hierarchically organized.

Habitat.

Cave, rocky/detritic/muddy/sandy bottom, coralligenous community, Posidonia oceanica meadow, lagoon, artificial reefs, epibiotic on Pinna nobilis . Bathymetric range 1-200 m.

Mediterranean caves.

La Catedral, Tunel LLarg, Petita de la Vaca caves (Balearic Sea); Galatea*, Falco*, Bisbe* caves (Sardinian Sea); Béar, Niolon caves (Gulf of Lions); western-Zoagli, Piccola Zoagli-Chiavari, Tunnel Zoagli-Chiavari, Eastern Bonassola caves (Ligurian Sea); Mago, Gaiola, Misteri, Tuffo Tuffo, Mitigliano caves (Central Tyrrhenian Sea); Infreschi Cave (Southern Tyrrhenian Sea); Taccio Vecchio 1 Cave-Lampedusa*, Tunnel of Cani Islands (Sicily Channel); Gamberi* Cave (Ionian Sea); Croatian caves (Northern Adriatic Sea); La Regina Cave (Southern Adriatic Sea); Farà Cave (Aegean Sea) ( Vacelet 1959; Sarà 1961a, 1962, 1964a; Labate 1964, 1965; Rützler 1966; Boury-Esnault 1971; Pulitzer-Finali and Pronzato 1976; Pansini et al. 1977; Pulitzer-Finali 1977; Bibiloni et al. 1984b, 1989; Ben Mustapha et al. 2002; Pronzato and Manconi 2011; Bakran-Petricioli et al. 2012; Cadeddu 2012; Gerovasileiou and Voultsiadou 2012).