Moss animals (Bryozoa)

Taxonomic group

Phylum: Bryozoa

Diagnostic features

Bryozoans are coral-like animals in that they are colonial, building networks of branching tubes attached to the bed. The small animals (zooids) live near the ends of the tubes, and extend a crown of tentacles (the “lophophore”) into the current. Bryozoans are sometimes known as “moss animals” as the branching colonies may look moss-like.

Bryozoa. Live specimen showing tentacles. Image: Stephen Moore Image — Bryozoa. Live specimen showing tentacles. Image: Stephen Moore

Bryozoa. Preserved specimen with tentacles withdrawn. Image: Stephen Moore Image — Bryozoa. Preserved specimen with tentacles withdrawn. Image: Stephen Moore

Typical habitats

Bryozoans are found in many streams and ponds, where they attach to aquatic plants, woody debris, stones and even snail shells.

Feeding

They use the lophophore tentacles to capture small drifting food particles including phytoplankton and zooplankton.

Indicator value

Bryozoans are common in habitats with good water quality, but also in habitats with obviously degraded water quality. A soft bottom tolerance value of 4.0 has been assigned, but no hard bottom tolerance value has been assigned.