Podded Hydroid

Overview

The Podded Hydroid (Aglaophenia pluma) is a colonial marine organism that forms distinctive, feather-like structures. These colonies are commonly found in shallow coastal waters, where they attach to firm substrates or specific brown algae.

Appearance

This species typically grows as an erect, brown, feather-shaped colony. The central stem supports alternating, unbranched side branches, with feeding polyps facing upward. A key identifying feature is the presence of reproductive structures known as corbulae, which resemble small, basket-like or pine-cone-shaped pods that replace normal side branches.

Distribution & Habitat

Often found in shallow water, including rock pools and the lower shore, this hydroid is frequently associated with the brown seaweed Halidrys siliquosa. It also colonizes rock surfaces, particularly in exposed areas. While widely reported, its global distribution is broad, spanning the Mediterranean and the Northeast Atlantic.

Biology & Behavior

Each feeding polyp is protected by three specialized defensive polyps. The colony is known to have a sting that may cause swelling if it comes into contact with human skin. Certain nudibranch species, such as Doto koenneckeri and Eubranchus farrani, are known to feed on these hydroids.