Description: This ascidian forms a small colony consisting of a tough basal sheet from which the zooids arise. They are free aside from a stolon that is usually not visible. The zooids are very small, transparent, and would be very inconspicuous if it were not for the fact that each one has a white cross-shaped mark (Maltese cross) between the siphons.

Habitat: Hard substrata in the subtidal from around 10 m to 30 m. May prefer areas with good water movement.

Distribution: Recorded all around Britain and Ireland but so far seems to be absent from north of Scotland.

Similar Species: Could be confused with Pycnoclavella aurilucens but P. aurilucens has three golden or white spots on the zooid, while this species has a white cross-shaped mark

Key Identification Features:

• Small colonial ascidian with stoloniferous zooids attached to a basal colony.
• Zooids are very small and mostly transparent, aside from white, cross-shaped mark between the siphons.

Distribution Map from NBN: Pycnoclavella stolonialis at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Pycnoclavella stolonialis at iNaturalist World Species Observations database.

GBIF data for Pycnoclavella stolonialis

WoRMS: Pycnoclavella stolonialis at World Register of Marine Species. Accepted name: Pycnoclavella stolonialis Pérez-Portela R., Goodwin C.E., Picton B.E. & Turon X., 2010. AphiaID: 477462.

Classification: Biota; Animalia; Chordata; Tunicata; Ascidiacea; Aplousobranchia; Clavelinidae; Pycnoclavella