Diadumene lineata (Verrill, 1869)

Orange-striped anemone

Diadumene lineata

Description: The column of this sea anemone is distinctly divided into scapus and capitulum, with a pemanent parapet and fosse. The tentacles are slender, often very long, up to about 100 in number. Acontia are present, and are fairly readily emitted through holes in the column. Usually measures about 10mm across base but may be larger. The typical colour of the scapus is olive green or brownish, rarely pink, usually with vertical stripes of orange, yellow, or white. The capitulum, disc and tentacles are translucent grey or greenish, occasionally flecked with white or crimson. Reproduces by longitudinal fission - dividing vertically into two approximately equal parts

Habitat: Usually found on the shore but may also occur in the shallow sublittoral. Lives in pools attached to rocks or shells, frequently amongst mussels. Also occurs in brackish-water creeks and lagoons, in estuaries, etc. Frequently found in harbours or other places near shipping lanes.

Distribution: Rather local but recorded on all British coasts. This anemone appears to have spread throughout the northern hemisphere during the past century, probably being carried on ship's bottoms or introduced with living oysters or other shellfish.

Similar Species: Young specimens of Metridium dianthus may be similar in form but are never striped and do not reproduce by longitudinal fission. Small green specimens of Actinia equina may have irregular pale streaks on the column but always have warts in the fosse and shorter tentacles.

Key Identification Features:

• No other British anemone has orange (or yellow/white) stripes on the scapus. These may be absent but unstriped individuals have never been recorded in Britain.

Distribution Map: NBN map : National Biodiversity Network mapping facility, data for UK.

WoRMS: Species record : World Register of Marine Species.

iNaturalist: Species account : iNaturalist World Species Observations database