Reevaluation of stalked aplysinid sponges, with description of a new species from the upper Bahamian slope

A new aplysinid sponge, Aplysina bathyphila n, sp., is described from the u pper Bahamian slope, where its populations show a stenobathic distribution limited to the range between 60 and 150 m deep. The species is characterize d morphologically by a stalked, goblet-shaped body and a large oscular diap hragm. The sponge body is hollow, having a spacious atrial cavity that beco mes a narrow canal extending the whole length of the stalk. The skeleton is a highly regular network of hexagonal meshes built with a single type of l aminated, pithed fibers, as is typically in the genus Aplysina. Choanocyte chambers are spherical. Apart from A. bathyphila, two other stalk bearing s pecies had previously been described in the genus, Aplysina pedunculata and Aplysina aztecus. However, on the basis of skeletal traits, we conclude th at A. bathyphila is the only stalked sponge belonging to the genus Aplysina . Aplysina pedunculata and A. aztecus, characterized by a nearly dendritic pattern of fibers with a highly developed pith, are transferred to the genu s Suberea in the Family Aplysinellidae.