Swartschewskia khanaevi sp. nov. A sponge surface B ectosomal skeleton C cross section of skeleton D, E secondarily microspined tuberculated spines on strongyles F strongyles. Abbreviations: chs choanosomal skeleton, Cp Cocconeis placentula, dm dermal membrane, es ectosomal skeleton, ia inhalant apertures, Lsp Lagenophrys sp., st spicular tracts. Scale bars: 10 μm (D, E), 100 μm (F), 500 μm (A), 1 mm (B).