Polymastiidae and Suberitidae (Porifera: Demospongiae: Hadromerida) of the deep Weddell Sea, Antarctic * Author Plotkin, Alexander S. Author Janussen, Dorte text Zootaxa 2008 1866 95 135 journal article 10.5281/zenodo.183878 810a9086-292c-4ca4-8075-91312cfac96e 1175­5326 183878 Genus Rhizaxinella Keller, 1880 Diagnosis (sensu van Soest 2002 ): Pedunculate sponges, with spherical, ovoid or cylindrical body carried on a simple or ramified stalk, normally attached to the substrate by a root system; usually an apical oscule. Body with a more­or­less radial skeleton and with brushes of spicules at the surface, skeleton of the stalk a tightly packed mass of aligned megascleres, bound by spongin. Megascleres are tylostyles of different sizes with raphides in trichodragmas. Type species: Rhizaxinella clavigera Keller, 1880 (by monotypy) = junior synonym of Alcyonium pyrifera delle Chiaje, 1828.