Actinia equina

Overview

An adhesive base supports a smooth column with up to 192 retractable tentacles arranged in six circles. Red, brown, green and orange forms occur, often with blue acrorhagi near the upper margin. Tentacle counts and colours vary.

It lives on hard intertidal surfaces, including in estuaries, and tolerates drying and raised temperatures. When the tentacles of neighbouring anemones touch, the acrorhagi can sting the other animal, which may then retreat.

A 2005 Toxicon study isolated two peptide toxins from acrorhagi and characterized their precursors. Acrorhagin I has 50 residues and acrorhagin II has 44. The work links the observed encounters to molecules in the tissue and supports treating acrorhagi as specialized aggressive organs. Similar toxin sequences alone do not show close organismal kinship.

Origins & earliest records

MarLIN attributes the scientific name to Linnaeus, 1758. This dates naming, not evolutionary origin; original type material was not examined.

Evidence & interpretation

MarLIN species account (description, habitat, distribution, biology); abstract of Toxicon 46:768–774 (2005), DOI 10.1016/j.toxicon.2005.08.003.

Selected bibliography

Documented works and useful reading. This is not a list of every appearance.

1. 01

   Novel peptide toxins from acrorhagi, aggressive organs of the sea anemone Actinia equina

   · 2005

   Selected bibliography; Toxicon 46:768–774; abstract consulted.

2. 02

   Beadlet anemone (Actinia equina)

   · 2008

   Selected bibliography; MarLIN institutional species account.

Family & connections

A source-supported family tree or inspiration record has not yet been compiled for this profile. Related reading below indicates a connection in subject matter, not a proven lineage or creative influence.

References

Sources supporting this profile. Linked pages have their own scope and editorial standards.

1. Institutional species accountBeadlet anemone (Actinia equina)Research access: 2026-10-07
2. Peer-reviewed article abstractNovel peptide toxins from acrorhagi, aggressive organs of the sea anemone Actinia equinaResearch access: 2026-10-07

Image credits

A black side-view silhouette of a sea anemone with a broad base, thick column and many extended tentacles.

Attributed silhouette labelled Actinia equina in the individual source record; retained whole raster shows an outline, without colour, exact locality or diagnostic detail.