Hexadella racovitzai Topsent, 1896

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 : 46-47

Hexadella racovitzai Topsent, 1896 Fig. 39

Hexadella racovitzai Topsent, 1896: 119 (partim).

Description.

Growth form encrusting, thin, with lobes in large patches. Colour faded to pale pink in vivo, brownish in ethanol after releasing of a yellow fluid. Surface highly wrinkled by small evident collagenous reinforcements irregularly crossing and converging towards small conules; well developed (when compared to Hexadella pruvoti and Hexadella crypta ) star-shaped network of subdermal canals converging towards oscula; inhalant apertures inconspicuous. Oscules wide, at the apices of short chimneys. Ectosome notably thick. Choanosome soft, fleshy and fragile, difficult to cut. Large clusters of spherulous cells, common at the body surface, with large inclusions containing microgranules and microgranular cells; choanocyte chambers eurypylous (30 ± 6.3 × 19 ± 2 µm on average) in dense clusters. High natural toxicity.

Habitat.

Cave, coralligenous community, rocky cliffs. Bathymetric range 25-38 m. Already deeper than 100 m.

Mediterranean caves.

La Catedral Cave (Balearic Sea); Corail Cave (Gulf of Lions); Leuca caves (Ionian Sea); Stražica Cave (Northern Adriatic Sea); Farà, Agios Vasilios, Alikes caves (Aegean Sea) ( Pulitzer-Finali and Pronzato 1980; Bibiloni et al. 1989; Novosel et al. 2002; Reveillaud et al. 2010; Pronzato and Manconi 2011; Gerovasileiou and Voultsiadou 2012).