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Svenzea? tubulosa

Description: The typical individual consists of single or groups of slender tubes or cylinders, sometimes ramified, up to 5-10 cm long and 1-2 cm wide, arising from crevices in the substratum; oscules on top or sometimes on the sides of tubes, often in groups and sometimes keyholed; there can also be orifices in the sides of the tubes. Sometimes there are massive bushy projections aside or around tubes, with many lamellate, 2-5 mm-long outgrowths, which are often fouled. Very large individuals form entangled and anastomosed tubes and cylinders arising from a partly buried, partly exposed basal mass. Endolithic parts have not been examined. External color usually lemon yellow (sometimes tinged violet or purple), but can be tan, orange or brown; subsurface color purple, interior color cream. Consistency compressible but somewhat easy to tear (crumbly). Skeleton of ascending and interconnecting spicule tracts with 1- 10 spicules in cross-section, enveloped by spongin, 30-80 µm in diameter, forming a scaffold-like reticulation where ascending tracts are slightly stouter, with 125-425 µm meshes. In tube walls the reticulation ascends and diverge radially from the inner to the outer surface. At the surface, brushed endings of ascending tracts support the pinacoderm. Deeper in the choanosome there are many loose spicules partly obscuring the main reticulation. Spicules of the Bahamian material are slightly curved or slightly sinuous styloids, with one of the ends narrower or mammiform; developmental stages are oxeote with blunt ends; size 170-340 µm long and 2.5-10 µm wide. Spicules of material from the continental coast of Colombia are robust anysostrongyloxea or anysoxea, slight to quite curved in the basal half, with narrower or telescoped heads, 300-430 µm long and 7-18 µm wide.

Notes: This is a shallow and reef species living partly exposed. It was originally described under genus Scopalina. It is currently placed in Svenzea in the WPD. The tentative genus allocation made here is due to its similarity in texture, color and skeleton to Svenzea? flava (Lehnert & van Soest, 1999), also pictured here, both lacking the strongly pigmented cells diagnostic for the genus Svenzea (see Alvarez et al., 2000). Small specimens of S? flava could be also confused with S? tubulosa, but should be distinguished by the tendency of the latter to form tubular or bushy projections that arise from the substratum (see notes under S? flava). This species may be also confused in the field with Ectyoplasia ferox (Duchassaing & Michelotti, 1864), also pictured here, which has different spicules (stout styles and smaller styles spined at the tip in E. ferox, styloids to anysostrongyloxea in S? tubulosa) and skeleton (plumose ascending, echinated tracts in E. ferox vs. ascending and interconnected tracts forming a reticulation in S? tubulosa). Also, E. ferox is a bit stiffer and may have tubes, but arising from an encrusting base, while the base in S? tubulosa is buried. In fact, Díaz et al. (1993) considered S. tubulosa a junior synonym of Hymeniacidon amphilecta de Laubenfels, 1936, and the latter to belong to the genus Ectyoplasia; Indeed, H. amphilecta is currently considered a junior synonym of E. ferox (see WPD).

Author Reference: (Alcolado & Gotera, 1986)


Link: World Porifera Database