acrorhagus

invertebrate anatomy

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Last updated

July 23, 2026

Quick Summary

The term "acrorhagus" refers to a specific anatomical feature found in certain sea anemones. These are marginal tubercles, meaning they are located on the edge or rim of the anemone. Each acrorhagus is essentially a localized cluster of nematocysts, which are stinging cells used for defense and capturing prey.12

In sea anemones, acrorhagi play a role in inter-species competition for space. When two anemones encounter each other, they may inflate these acrorhagi and use them to attack, potentially leading to the death or retreat of one or both individuals.2

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cnidarian
Ecology and habitats
…with nematocyst-studded fighting structures (acrorhagi) located below the tentacles. Attacks may result in the death of one of the anemones, or both may retreat. Tentacle touching is involved in the recognition of non-clonemates, which presumably is chemically mediated.
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…with nematocyst-studded fighting structures (acrorhagi) located below the tentacles. Attacks may result in the death of one of the anemones, or both may retreat. Tentacle touching is involved in the recognition of non-clonemates, which presumably is chemically mediated.
Read More