Morphological description (show/hide)
| Flabellate, palmate-digitate or simply digitate sponges, occasionally massive, subspherical, varying considerably in size (70-340mm long, 45-140mm maximum width, 10-20mm thickness), and varying in development of digits, typically consisting of several short or long cylindrical digits (15-140mm long), arising from margins of a fan, or at least with an enlarged point of attachment for digits above basal stalk, usually with short cylindrical stalk (30-50mm long) often attached to coral rubble or dead molluscs. | | Bright red-orange alive (Munsell 5R 5/10), ra | | NOMINOTYPICAL VARIETY - Optically smooth, even, membraneous surface when alive, with few microconules on margins of digits, none on lateral surfaces of fans, ectosomal membrane destroyed upon preservation, surface beneath membrane very porous, with numerous ostia approximately 0.5-1mm diameter. Oscules, 2-3mm diameter, surrounded by symmetrical membraneous lips which usually collapse upon preservation, slightly raised (up to 2mm) from surface, without any obvious subdermal drainage system, oscules located mainly on margins or less frequently scattered over lateral surfaces in live material, but these are not easily visible after preservation. VARIETY WITH ASTRORHIZAE - Oscules raised above surface with prominent subdermal drainage canals radiating away from central pore, and surrounded by slightly raised membraneous lips, producing prominent subdermal sculpturing. VARIETY WITH FISTULES - Oscules on upper and lateral surfaces (of subspherical massive growth forms), raised above surface on relatively large fistules, up to 12mm long, 4mm diameter, without drainage canals or other surface sculpturing. However, fistules artificial, membraneous, collapsing upon preservation. | | Skeleton reticulate, spongin fibres heavy, relatively widely spaced (230-400um mesh size), spongin fibres divisible into primary and secondary components, primary fibres (80-115um diameter) sparsely cored by uni- or paucispicular tracts of choanosomal principal styles, usually ascending towards peripheral region, primary fibres heavily echinated by acanthostyles, dispersed relatively evenly over all fibres, many primary fibres also contain sand grains, but these do not usually occupy entire fibre diameter, secondary fibres (20-45um diameter) usually uncored, without detritus, but heavily echinated by acanthostyles, collagen moderately heavy, containing abundant microscleres, choanocyte chambers oval, 50-80um diameter. | | Single category of auxiliary spicules (subectosomal subtylostyles) forms irregular paratangential brushes on surface. Surface mineral skeleton not dense, usually consisting of bundles, occasionally individual spicules embedded in or dispersed between relatively close-set, horny spongin fibres, fibres marginally smaller but more compacted (80-140um mesh size) in peripheral skeleton than in axis of choanosome, small quantities of detritus (mostly sand grains) embedded in peripheral skeleton, but less abundant than in axis, light brown collagen and numerous microscleres abundantly scattered in periphery. Plumose tracts of choanosomal styles, in paucispicular tracts, terminate just below auxiliary spicules in the peripheral skeleton, and do not protrude through the sponge surface. | | Choanosomal principal spicules short, straight styles with slightly subtylote bases, rounded or abruptly pointed tips, usually completely smooth, occasionally with sparse spines over shaft and both ends, similar in morphology to auxiliary spicules, differentiated mainly by being slightly shorter and thicker (134-159 x 4.5-8). Subectosomal auxiliary spicules quasidiactinal modifications of styles, long, straight with slightly subtylote microspined bases, rounded microspined points, completely smooth shaft (162-206 x 2.5-4). Echinating acanthostyles short, cylindrical, slightly subtylote bases, rounded, slightly swollen tips, evenly spined, spines small, granular (58-91 x 4-7). | | Palmate isochelae small, unmodified (12-17). Toxas with consistent morphology, variable in size, slightly curved at centre, recurved and sharply pointed at tips (24-122 x 0.8-3). |
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