Morphology of the Skeleton of a Fossil Carboniferous Sponge of the Genus Aplysinofibria Bolkhovitinova, 1923, in Comparison with Some Extant Dictyoceratid and Verongid Sponges (Keratosa)

Morphological structures observed in a fossil Carboniferous sponge of the genus Aplysinofibria Bolkhovitinova, 1923 are compared with the details of the skeletal structure of extant keratose (horny) sponges. The most typical anatomical features of skeletons of the extant dictyoceratid and verongid sponges are compared with polygonal tubular structures of the skeletons of the fossil Aplysinofibria. Based on the similarity of the main elements of fiber branching in recent and fossil sponges, an assumption is made about the primary keratose (horny) skeleton of the Carboniferous Aplysinofibria. An experimental model of an artificially mineralized extant keratose (horny) sponge Hippospongia sp. shows its similarity to mineral pseudomorphoses (biomorphoses) composing the structures of the Aplysinofibria skeleton.