Pleraplysilla spinifera (Schulze, 1878)

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 : 19-20

Pleraplysilla spinifera (Schulze, 1878) Fig. 14

Spongelia spinifera Schulze, 1878b: 152.

Description.

Growth form encrusting, up to 2 cm thick, as irregular patches (several cm in diameter) characterized by a smooth and conulose mucous surface. Conules very evident, up to 8-10 mm in height. Colour from whitish to very light brown. Consistency very soft. Exhalant and inhalant apertures (up to 1 mm in diameter) irregularly scattered on the surface. Skeleton of dendritic fibres generally arborescent with 2-5 branches. Each fibre with a basal plate strictly adhering to the substrate. Spongin laminated and cored by sand grains and spicule fragments. These stout fibres (1.5-2.0 mm in height) can reach 400 µm in diameter at their base, with a sandy core of 80 µm. Fibres usually light yellow and transparent show, in many cases, a red-brown colour due to microscopic algae.

Habitat.

Cave, rocky/detritic/muddy bottom, red coral bank, coralligenous community, artificial barriers, boulders, Posidonia oceanica meadow. In many cases massive specimens, not over 5 cm in diameter, of this species are epibiotic on gorgonians and Pinna nobilis . Bathymetric range 1-500 m.

Mediterranean caves.

Blava, La Catedral, Blu, Misidacis, Meda Petita, Petita de la Vaca caves (Balearic Sea); Galatea*, Falco*, Bisbe* caves (Sardinian Sea); Béar, Endoume, Figuier, Tremier, Niolon, Bagaud caves (Gulf of Lions); Secca delle Formiche -Vivara Cave (Central Tyrrhenian Sea); Gamberi* Cave (Ionian Sea); Croatian caves (Northern Adriatic Sea); Piccolo Ciolo, Marinella, Principessa caves (Southern Adriatic Sea); Farà, Agios Vasilios, Vouliagnemi caves (Aegean Sea) ( Vacelet 1959; Boury-Esnault 1971; Pouliquen 1972; Pulitzer-Finali and Pronzato 1976; Pulitzer-Finali 1977; Bibiloni et al. 1984a, 1989; Harmelin et al. 2003; Martì et al. 2004; Bussotti et al. 2006; Turon et al. 2009; Pronzato and Manconi 2011; Bakran-Petricioli et al. 2012; Cadeddu 2012; Gerovasileiou and Voultsiadou 2012).

Remarks.

Among the Dictyoceratida, the genus Pleraplysilla has a dendritic not anastomosing skeleton.