An overview of the Mediterranean cave-dwelling horny sponges (Porifera, Demospongiae) Author Manconi, Renata Author Cadeddu, Barbara Author Ledda, Fabio Author Pronzato, Roberto text ZooKeys 2013 281 1 68 http://dx.doi.org/10.3897/zookeys.281.4171 journal article http://dx.doi.org/10.3897/zookeys.281.4171 1313-2970-281-1 Ircinia oros (Schmidt, 1864) Fig. 16 Hircinia oros Schmidt, 1864: 29. Description. Growth form massive, lobate, with large size (20-30 cm in diameter and 10-15 in height). Each lobe usually bears a large oscule (30-60 mm in diameter), sometimes at the end of a short funnel (1 cm high). Colour medium to dark grey in vivo. Surface covered by a slim layer of very fine and regular mineral sediment engulfed in a slender regular network showing a lighter colour. Conules (1-2 mm in height) regularly distributed, 24 mm apart. Choanosomal skeleton rust coloured and rich in fibres and filaments. Skeleton network of cored primary fibres (200-250 µm in diameter) and free (or almost free) secondary fibres (100-200 µm ). Filaments (9-13 µm ) with an oval knob (15-22 µm ). Habitat . Cave, detritic and rocky bottom, coralligenous community. Specimens of this species are frequently covered by large specimens of Haliclona (Reniera) cratera ( Schmidt 1862 ). Bathymetric range 1-150 m. Mediterranean caves. Blava, La Catedral, J1, Blue, Misidacis caves (Balearic Sea); Galatea*, Falco*, Bisbe* caves (Sardinian Sea); Endoume, Figuiers caves (Gulf of Lions); Western-Zoagli Cave (Ligurian Sea); Lacco Ameno, Tuffo Tuffo caves (Central Tyrrhenian Sea); Monastir, Salakta caves (Sicily Channel); Mazzere* Cave (Ionian Sea); Croatian caves (Northern Adriatic Sea); Trypia Spilia, Ftelio, Fara , Madhes, Alikes caves (Aegean Sea) ( Sara 1960a , 1964a ; Ruetzler 1966 ; Pouliquen 1972 ; Bibiloni et al. 1989 ; Ben Mustapha et al. 2003 ; Marti et al. 2004 ; Turon et al. 2009 ; Pronzato and Manconi 2011 ; Bakran-Petricioli et al. 2012 ; Cadeddu 2012 ; Gerovasileiou and Voultsiadou 2012 ). Figure 16 Ircinia oros . a specimen with an epibiotic haliclonid (lightest area) b magnifications (LM) of typical irciniid skeletal filaments c schematic drawings of cored primary fibres, uncored secondary network and a filament with the terminal knob. c modified from Rubio-Lois et al. (1981) .