Description: A small solid bivalve with a broadly triangular outline, which reaches up to around 13 mm. Main colour is white but there are usually tinges of blue at the growth lines, which are clear in this species. Shell may be partially or almost fully covered by the matt grey, green-brown to yellow-green periostracum. There are fine radiating lines and some striations visible on the outer surface of each valve. There is a group of 16-25 teeth at the anterior of the hinge line and a group of 11-14 at the posterior. Inside of shell with a pearly sheen.

Habitat: Muddy gravel and coarse sand down to around 150 m depth.

Distribution: Found on all coasts around Britain and Ireland.

Similar Species: Could be confused with Nucula nitidosa or Nucula sulcata.

Key Identification Features:

• Matt grey, green-brown to yellow-green periostracum.
• 16-25 anterior teeth on hinge line.
• 11-14 posterior teeth on hinge line.

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

iNaturalist: Nucula nucleus at iNaturalist World Species Observations database.

GBIF data for Nucula nucleus

WoRMS: Nucula nucleus at World Register of Marine Species. Accepted name: Nucula nucleus (Linnaeus, 1758). AphiaID: 140590.

Classification: Biota; Animalia; Mollusca; Bivalvia; Protobranchia; Nuculida; Nuculoidea; Nuculidae; Nucula