Mitchell, Kirsty D.; Hall, Kathryn A.; Hooper, John N. A.
Sigmaxinella hipposiderus Mitchell, Hall & Hooper, 2011, sp. nov.
A new species of Sigmaxinella Dendy, 1897 (Demospongiae, Poecilosclerida, Desmacellidae) from the Tasman Sea
FIGURE 2. Sigmaxinella hipposiderus sp. nov. Holotype (QMG 323175), habitus, scale bar = 25 mm. A, specimen on deck; B, specimen after preservation in ethanol (70 %).
FIGURE 3. Schematic representation of skeletal arrangement of Sigmaxinella hipposiderus sp. nov., scale bars = 1000 μm. A, schematic of cross-section taken through upper branch of specimen (as indicated by the double-arrow ‘ a’ on whole specimen image); B, schematic of cross-section taken through lower stalk of specimen (as indicated by the double-arrow ‘ b’).
FIGURE 5. Scanning electron micrographs of spicule complement from Sigmaxinella hipposiderus sp. nov. A, megascleres are represented by two types of styles, with the long straight styles dominant, scale bar = 200 μm; B, image of microscleres in the mesohyl, showing microxeas forming bundles, but not organised into true trichodragmata, scale bar = 50 μm; C, microxea, smooth and isodiametric, scale bar = 10 μm; D, sigma, c-shaped and without any spines on hooks, scale bar = 10 μm.
FIGURE 6. Comparison of gross morphology of species of Sigmaxinella Dendy, 1897 found in Australian waters. A, S. australiana Dendy, 1897; B, S. soelae Hooper, 1984; C, S. dendroides Whitelegge, 1907; D, S. viminalis Hallmann, 1916; E, S. flabellata (Carter 1885) sensu Dendy, 1897; F, S. ramosa (Carter, 1883); image A from Hallmann (1916, pl. XXXIII, Fig. 1); image B from Hooper (1984, p. 8, Fig. 1); image C from Whitelegge (1907, pl. XLVI, Fig. 42); image D from Hallman (1916, pl. XXXIII, Fig. 4); image E from Hallmann (1916, pl. XXXIII, Fig. 5); image F original, syntype of Phakellia ramosa Carter, 1883, specimen BMNH 1884.4. 14.2, collected from Sydney region; images A – D and E – F to same proportion, both scale bars = 50 mm.