Genus Cliothosa Topsent, 1905

Synonymy. Thoosa sensu Topsent, 1888 .

Diagnosis. Excavating sponges in alpha morphology with large tylostyles and amphiasters. Amphiasters most commonly delicately branching, slim-rayed, with terminal branching, but less fragile forms in different species. Only in choanosome. Reduced forms of amphiasters occasionally in papillae or terminally in blind erosion canals. Occurrence and predominance of different amphiaster types depending on specimens or species (adapted from Rützler 2002).