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Keel worm


up to 5 centimeters


tube: white




not tasty for eating



  • Dut: Kalkkokerworm, driehoeksworm, spiraalkokerworm.
  • Lat: Pomatoceros lamarcki, Pomatoceros triqueter, Spirorbis borealis, Spirorbis spirorbis
  • Eng: Keel worm
  • Ger: Dreikantröhrenwurm, Posthörnchenwurm
Tubeworms, Foto Fitis,

Keel worms

You often find keel worms on fish crates and other drifting objects which wash ashore. There are all kinds of species. The large tubes in the picture above are from the Pomatoceros triqueter, which you also find on stones. The small spiral tubes are Spirorbis spirorbis, which are often found on large brown seaweed species such as bladder wrack. They eat plankton, which they filter through a crown of feathery tentacles.

  • Newcomers

    In 2010, two new species of keel worms were discovered for the Netherlands: Apomatus similis and Vermiliopsis stiaticeps. These worms were found on the underside of scarcely overgrown stone blocks in the Oosterschelde. Apomatus similis is a southern species found in the Mediterranean Sea, the French and Wales Atlantic coast and the English Channel. Because this worm was found in the Oosterschelde close to a yacht harbor, scientists think that the animal arrived attached to a pleasure yacht. Vermiliopsis stiaticeps comes originally from West-Africa, the Canary Islands, Madeira, Azores, Portugal and northern Spain, Brittany and southwestern Great Britain. Scientists think that this worm probably arrived along with a shipment of shellfish to the Netherlands.

  • Distribution and habitat
    Keel worms on seaweed, Sytske Dijksen,

    Keel worms are found in all the seas around the world, living on stones or drifting objects. Some species live on large seaweed species.