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Image from Identification and Ecology of Australian Freshwater Invertebrates.
Phylum Nemertea (ribbon worms, proboscis worms)

The Phylum Nemertea (1150 spp.) is predominantly marine, but ca. 25 species are known from fresh waters. Three species in two genera are known from North America (Sundberg & Gibson, 2008).

The nemerteans are known as the “proboscis worms” for their eversible proboscis, which they use to capture prey and support their carnivorous life-style. They possess a complete one-way gut, allowing for regional specialization of the alimentary canal and more efficient digestion than the blind sac seen in Platyhelminthes. Nemerteans have a closed-but-low-pressure circulatory system. The central nervous system is of the protostome type with two ventral nerve cords joined by lateral connectives. Freshwater nemerteans are generally in the mm to cm size range.

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Bibliography

  • Zhang, Z.-Q. 2011. Animal biodiversity: An introduction to higher-level classification and taxonomic richness. Zootaxa 3148: 7-12. [Available online]
  • Kolasa, J. & S. Tyler. 2010. Flatworms: Turbellarians and Nemerteans. [in] J.H. Thorp & A.P. Covich (eds.). Ecology and Classification of North American Freshwater Invertebrates, 3rd edition: 143-161.
  • Sundberg, P. & R. Gibson. 2008. Global diversity of nemerteans (Nemertea) in freshwater. Hydrobiologia 595: 61-66. [Available online]
  • Watermolen, D.J. 2005. Aquatic and terrestrial flatworm (Platyhelminthes, Turbellaria) and ribbon worm (Nemertea) records from Wisconsin. Research/Management Findings, Wisconsin DNR (55). 8 pp.
  • Brusca, R.C. & G.J. Brusca. 2003. Invertebrates, 2nd edition. Sinauer Associates, Inc., Sunderland, Massachusetts. 936 pp.
  • Smith, D.G. 2001. Nemertea (Proboscis worms). Pennak's Freshwater Invertebrates of the United States, 4th edition: 109-115.
  • Gibson, R. & J. Moore. 1976. Freshwater nemerteans. Zoological Journal of the Linnean Society 58: 177-218. [Available online]
  • Browning, R.F. 1972. A record of the freshwater nemertean, Prostoma rubrum, in Wisconsin. Transactions of the Wisconsin Academy of Science, Arts & Letters 60: 179-180. [Available online]
  • Coe, W.R. 1959. Nemertea. [in] W.T. Edmondson (ed.). Ward & Whipple Fresh-Water Biology, 2nd edition: 366-367.

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Classification of Freshwater Taxa

Only taxa found in North America are listed. Formatting indicates if they are known (to us) from North America, the midwestern states or Wisconsin.

Kingdom Animalia [details]
Subkingdom Eumetazoa [details]
clade Bilateria [details]
clade Protostomia [details]
clade Spiralia [details]
Superphylum Lophotrochozoa [details]
Phylum Nemertea (ribbon worms, proboscis worms) [details]
  .   Class Enopla [details]
  .    .   Order Hoplonemertea [details]
  .    .    .   Suborder Monostilifera (+ Cratenemertea, + Eumonostilifera) [details]
  .    .    .    .   Family Tetrastemmatidae [details]
  .    .    .    .    .   Genus Prostoma [details]
  .    .    .    .    .    .   Species P. graecense (+ P. rubrum), P. asensoriatum, P. canadiensis, P. eilhardi
  .   Class Anopla [detail]

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