- Kingdom: Animalia
- Phylum: Porifera
- Class: Demospongiae
- Order: Poecilosclerida
- Family: Hymedesmiidae
- Scientific name: Hymedesmia paupertas
- Norwegian: -
This sky blue, encrusting sponge, forms 10-15 mm thick sheets covering hard surfaces. The vivid color makes it easy to distinguish it from any other sponge in the North-East Atlantic.
Often seen on hard, rocky substrate, often, but not necessarily on current exposed locations. Species from this order are found along the entire coast. It is registered on all depths, down to 400 meters.
It is common along most coasts along the European coasts.