Craniella Schmidt 1870

Genus Craniella Schmidt, 1870

Definition. Globular sponges without porocalices and with a distinct single- or double-layered cortex visible to the naked eye. When present, the outer cortical layer often has sub-dermal cavities and the inner layer is composed of collagen and a tight arrangement of cortical oxeas. Presence of direct-developing embryos within the sponge tissue (amended from Carella et al. 2016).

Diagnosis. Globular sponges with conulose but optically smooth surface over most of the upper body; at the base, there are often bundles of spicules acting as a root. Oscules are few and usually apical. Ostia in sieve-like groups, overlying subdermal cavities. In cross-section, there is a distinctly visible cortex, which is often divided into a dense collagenous layer strengthened by radially or confusedly arranged special cortical megascleres, and a less dense outer layer in which there are many subdermal cavities. A single-layered cortex with tangential spicules may also occur. Choanosomal skeleton radiating in spiral fashion, with bundles of oxeas originating from a central focus and spiraling outwards towards the surface where they are mixed with protriaenes to protrude in groups and push up the ectosome into conical elevations. Megascleres are protriaenes, anatriaenes, choanosomal oxeas and shorter cortical oxeas. Microscleres are sigmaspires, which are absent in some species (amended from van Soest & Rützler 2002).