Description: This worm reaches up to 50 cm in length and 3-4 mm wide. It is normally grey-green to blue-green, occasionally bright green, on the upper surface and lighter underneath. The outer edges of the body may be cream. It has a rounded, flat head on which there are 20-30 eyes per side, although these are not visible unless the specimen is cleared so will not help for field identification. The stylet (piercing mouthpiece) is rounded, with a long and slender basis.

Habitat: From lower shore down to 100 m depth. Found on silt, gravel or sand substrate; under boulders, in kelp holdfasts, amongst Mytilus and in crevices.

Distribution: A few scattered records around Britain and Ireland, probably under-recorded due to cryptic nature or inability to reliably identify to species level in the field.

Similar Species: There are other ribbon worms in Britain and Ireland, and even others in the genus Emplectonema, but the colouration of this worm coupled with the shape of the stylet should distinguish it from other species.

Key Identification Features:

• Long worm reaching up to 50 cm.
• Grey-green, blue-green or bright green on dorsal surface; lighter on ventral surface.
• Outer edges of body may have cream coloured margin.
• Stylet is rounded.

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

iNaturalist: Emplectonema gracile at iNaturalist World Species Observations database.

GBIF data for Emplectonema gracile

WoRMS: Emplectonema gracile at World Register of Marine Species. Accepted name: Emplectonema gracile (Johnston, 1837). AphiaID: 122710.

Classification: Biota; Animalia; Nemertea; Hoplonemertea; Monostilifera; Eumonostilifera; Amphiporina; Emplectonematidae; Emplectonema