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 Major Groups | Nemertea (proboscis worms)

Nemertea (proboscis worms)

Descriptive Features:

  • 3 pairs of lateral eyespots
  • mouth located under proboscis
  • body unsegmented, very thin, worm-like, smooth, covered with cilia, no appendages or setae, tapered posteriorly, blunt anteriorly
  • very long muscular proboscis, with apical stylet, anteriorly
  • anus at posterior end
  • Total length: up to 30 mm 
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    Distribution: Eastern Australia. It is believed to be introduced.

    Sensitivity Rating: SIGNAL grade 3

    Functional Feeding Group: predator, gathering collector

     

    Murray River, Yarrawonga Vic

    Ecology: Proboscis worms occur in well oxygenated shallow littoral areas of standing waters and sluggish backwaters of streams. They are free living and can be found amongst vegetation, especially the under surface of leaves. Nemerteans glide by cilia action along its own slime secretion. They are detritivores and carnivores on metazoans (aquatic invertebrates other than protozoans) in particular small oligochaetes. The proboscis is used for feeding and defence, when not in use it is retracted into a sac (rhynchocoel). Proboscis worms reproduce sexually. They are hermaphrodites with both self and cross fertilisation occurring. A mucous sheath is formed, into which unfertilised eggs and sperm are placed. Fertilisation takes place in the sheath where the eggs develop directly into fully formed worms. There is no larval stage.

     

    Information Sources: Williams 1980, Hawking & Smith 1997

     

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