Sponges of the Guyana Shelf Author Van, Rob W. M. text Zootaxa 2017 1 1 225 journal article 37320 10.5281/zenodo.272951 e2c88f4c-3ac2-45f9-95e4-99b75561a081 1175-5326 272951 6D68A019-6F63-4AA4-A8B3-92D351F1F69B Tedania (Stylotedania) folium subgen. nov. sp. nov. Figures 104 a–e Material examined. Holotype RMNH Por. 9324, Guyana , ‘Luymes’ Guyana Shelf Expedition, station 107, 7.7°N 57.5°W , depth 65 m , muddy sand bottom with shells, 5 September 1970 . Description. The sponge forms smooth, thin, leaf-like shapes ( Fig. 104 a) with irregular margins. The available material consists of two almost equally large fragments, 7 x 4–5 cm in size, thickness varying between 2 mm at the outer margins to about 1 cm at the attachment to the substratum. Both fragments are presumed to be from the same larger individual attached at several points on shells and rubble. It is likely but not certain that the leaf-like forms were growing erect. There are no identifiable oscules. Color (alcohol) pale beige, with a faint rosy tinge. Consistency soft, limp, easily torn. Skeleton. The choanosomal skeleton is plumose, with a large proportion of loose unorganized spicules and tracts of thicker styles forming wide meshes. No visible spongin. The ectosomal skeleton is tangential and consists of loose thinner styles and onychaetes. Spicules. ( Figs 104 b–e) Styles, onychaetes. Styles in two more or less distinct categories, usually recognizable as (1) choanosomal spicules ( Figs 104 b,b1), thicker, usually slightly curved, and with mucronate or bluntly rounded points, rather uniform in size, 312– 348 –392 x 5.5– 7.1 –9 µm, and (2) ectosomal tornote-like spicules ( Figs 104 c,c1), thin, straight and gradually but sharply pointed, in a large size range, 198– 286 –365 x 2 – 2.4 –4 µm. Onychaetes in two distinct size categories, (1) long, straight or slightly wispy ( Figs 104 d,d1,d2), with prominent asymmetrically placed tyle, very common, 207– 243 –267 x 1 – 1.1 –1.5 µm, and (2) small and very thin ( Figs 104 e,e1,e2), tyle very close to the apex, not common, 42– 51 – 61 x <0.5 µm. Distribution and ecology. Guyana shelf, on muddy sand bottom attached to rubble, at 65 m depth. Etymology. The noun ‘folium’ (L.) means leaf, referring to the leaf-like shape of the sponge. Remarks. The two style types of the new species are in majority distinguishable as thick-curved vs. thinstraight, but some overlap is observed where a minority of choanosomal styles is straight. A further subtle distinction, but also with some overlap, is observed in the pointed ending of the spicules: ectosomal styles are invariably tapering gradually and sharply, whereas most choanosomal styles have blunt or mucronate endings.