Cretaceous sponges from the Campanian of Misburg and Höver
Rhizopsis horrida is a rare species, not previously reported from Misburg. The specimen shown has a fibrous appearance, with sinuous fibre strands radiating away from a point. As mentioned by De Laubenfels (1955), such aggregates are probably the remains of a formerly spherical sponge with a radiate skeleton.
The scleres are mainly amphioxes and amphistrongyles.
Rhizopsis horrida is not mentioned in the chapter on Cenozoic and Mesozoic demosponges of the recent Treatise (Finks et al., 2004). However, it is (inappropriately) described under the chapter on Paleozoic demosponges (page 21 of Finks et al., 2004 ).