Description: This lugworm is usually seen through presence of its distinctive burrows in sand. They form J- or U-shaped burrows which have a 'blow hole' at the front, in the form of a noticeable depression in the sand, and a slightly messy worm cast at the rear which has the appearance of a piled up string of clean sand which is excreted by the worm as it burrows. The worm itself has a firm cylindrical body 12-20 cm in length, and is usually pink to red in colour. but may sometimes be dark green to black. There are branching dorsal gills on segments 7-19. The head is small and blunt and lacks appendages aside from a rough proboscis.

Habitat: In a J- or U-shaped burrow in sand or muddy sand. Found intertidally, from high water mark to lower shore.

Distribution: Widespread around all coats of Britain and Ireland.

Similar Species: Potentially confused with black lugworm, Arenicola defodiens, which is much darker in colour and burrows much more deeply. It also doesn't usually form a 'blow hole.'

Key Identification Features:

• Distinctive burrows with blow hole and casts.
• Firm, cylindrical body.
• Small, blunt head.
• Branching dorsal gills on segments 7-19.
• Usually pink to red in colour.

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

iNaturalist: Arenicola marina at iNaturalist World Species Observations database.

GBIF data for Arenicola marina

WoRMS: Arenicola marina at World Register of Marine Species. Accepted name: Arenicola marina (Linnaeus, 1758). AphiaID: 129868.

Classification: Biota; Animalia; Annelida; Polychaeta; Sedentaria; Scolecida; Arenicolidae; Arenicola