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Marine Animal Encyclopedia

Cycliophoran Symbion pandora

Symbion pandora is the only known representative of the phylum Cycliophora. This minute animal was first described in 1995 by two Danish biologists. It was found clinging to the mouthparts of a Norway lobster (Nephrops norvegicus) that was dredged up from the North Sea, and the biologists must have looked very closely to have seen it at all. The female cycliophoran has a rounded body and is attached to the substratum by a short stalk and an adhesive disk. Attached to her are tiny dwarf males that never release their grip. It feeds by means of a mouth funnel surrounded by cilia and excretes via an anus next to the mouth. The cycliophoran's reproductive cycle is complex and involves both sexually and asexually produced free-swimming larvae.

The structure and habits of the cycliophoran are so unlike any other known organism that it was classified in a new phylum of its own. Molecular studies indicate that it may be related to rotifers (see Grazers) and wormlike creatures called acanthocephalans. The asexual reproduction is similar to that seen in some bryozoans.

  • Phylum Cycliophora
  • Length 0.3 mm
  • Depth Not recorded
  • Habitat Mouthparts of the Norway Lobster
  • Distribution North Sea