Biodiversity & Conservation

A fanworm - Ficopomatus enigmaticus

Ficopomatus enigmaticus

Image Judith Oakley - Close-up of Ficopomatus enigmaticus encrusting a marina buoy.
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Distribution map

Ficopomatus enigmaticus recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

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Ficopomatus enigmaticus is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Annelida Segmented worms e.g. ragworms, tubeworms & fanworms
Class Polychaeta Bristleworms, e.g. ragworms, scaleworms, paddleworms, fanworms and tubeworms
Authority Fauvel, 1923
Recent synonyms Mercierella enigmaticus
Map icon Recorded Distribution in Britain and Ireland Found at several locations around the British Isles, including north-east, south-west and north-west England, south-west Wales and off the coasts of County Galway, Ireland.
Habitat information icon Habitat information Ficopomatus enigmaticus inhabits warm shallow sublittoral waters as well as brackish estuaries, docks and lagoons. This species forms reefs on different types of hard substrate including rocks and solid surfaces such as hulls of ships and pipes.
Text page icon Description Ficopomatus enigmaticus is a fan-worm that forms thin, white, calcareous tubes that turn yellowish-brown with age and are up to 8 cm in length and 0.1-0.2 cm in diameter. Tubes are marked by fine, transverse rings that spread outwards, reflecting previous growth. Thousands of individuals grow together at an individul rate of up to 2 cm per month to form huge reefs up to 50 cm in height and 4 m across, varying in shape from circular to elongate depending on water flow. The worm's body consists of a head, a seven segmented thorax, a 50-120 segmented abdomen and a tail segment. It grows to up to 2.5 cm in length and is greenish or reddish-orange in colour. The head has paired lobes, each bearing green, darkly banded, feather-like feeding tentacles up to 0.3 cm long and arranged in a semi-circle. One or more of the tentacles are modified into a yellowish-brown, fig-shaped operculum with dark spines. The base of the head is surrounded by a tall, faintly ribbed collar. The segments of the thorax, except for the first, are marked by a dorsal faecal groove and bear bundles of chaetae in two rows. The segments of the abdomen, except for the first to third, bear bundles of two to five chaetae also in two rows. The pygidium bears two small lateral lobes.
Identifying features
  • Greenish or reddish-orange bodied tube-building fan worm.
  • Body up to 2.5 cm in length and divided into 7 thoracic segments and up to 50-120 abdominal segments
  • Most segments bear bundles of chaetae.
  • Head with paired lobes, each bearing green, darkly banded feather-like tentacles.
  • Operculum yellowish-brown, fig-shaped with dark, inwardly curved, chitinous spines.
Additional information icon Additional information Ficopomatus enigmaticus is a suspension-feeder. It has a planktonic larvae and reproduces by external fertilization. This species lacks true gonads and, although generally gonochoristic, hermaphroditism has been recorded in some populations.

This review can be cited as follows:

Saskiya Richards 2008. Ficopomatus enigmaticus. A fanworm. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 06/09/2010]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3335>