Tethya norvegica Bowerbank, 1872

Tethya norvegica

Description: Yellow spherical sponge with oscule or oscules at the centre of the upper surface. Yellow in colour, with trapped silt at the surface. Smaller than Tethya citrina, typically less than 20mm in diameter.

Habitat: In southwestern Norway this species occurs on steep rockfaces in the circalittoral zone, with Neocrania anomala and Swiftia pallida.

Distribution: Known from Norway, where it is quite common in several fjords, south to Scotland, where there is only one known record.

Similar Species: At present this species can only be distinguished from other Tethya species by examination of the spicules. The megasters have forked rays, which is very distinctive.

Key Identification Features:

• Small spherical yellow sponge
• Megasters with forked rays

WoRMS: Species record : World Register of Marine Species.

iNaturalist: Species account : iNaturalist World Species Observations database