Nemertea

Tubulanus annulatus, photographed by Steve Trewhella.


Belongs within: Lophotrochozoa.
Contains: Neonemertea.

The Nemertea, ribbon worms, are a phylum of mostly marine worms, though there are also some freshwater and terrestrial species. Among the major features of the group is the presence of an eversible proboscis contained in an anterior chamber called the rhynchocoel. Basal members of the Nemertea (commonly classified in the past as the 'Palaeonemertea' though that grouping is probably paraphyletic) the proboscis is unarmed and the musculature relatively simple with a single layer of longitudinal muscles inside the outer circular muscle layer.

Characters (from Gibson 2002): Epidermis ciliated. Ciliated alimentary tract with separate mouth and anus. Blood system closed, composed of distinct vessels or lacunae. Eversible muscular proboscis present, housed (when retracted) in fluid-filled tubular chamber (rhynchocoel) extending posteriorly above gut. Nervous system well developed, with paired lateral longitudinal nerve cords extending from lobed cerebral ganglia. Excretory system usually protonephridial.

<==Nemertea [Anopla, Nemertina, Nemertini, Palaeonemertea, Rhynchocoela]
    |--Archisymplectes EL11
    `--+--Carinina arenaria Hylbom 1957 TN03, K86
       `--+--+--Neonemertea TN03
          |  `--Carinoma [Carinomidae] TN03
          |       |--C. mutabilis Griffin 1898 TN03
          |       `--C. tremaphoros Thompson 1900 TN03
          `--+--Tubulaniformes C03
             |    |--Parahubrechtia C03
             |    `--Tubulanus [Tubulanidae] TN03
             |         |--T. annulatus (Montagu 1804) RP07
             |         |--T. polymorphus PP15
             |         |--T. punctatus (Takakura 1898) TN03
             |         |--T. rhabdotus Corrêa 1954 TN03
             |         `--T. sexlineatus (Griffin 1898) TN03
             `--Cephalothricidae [Archinemertea] TN03
                  |--Cephalotrichella G02
                  |--Procephalothrix TN03
                  |    |--P. filiformis (Johnston 1828) TN03
                  |    |--P. kiliensis Friedrich 1935 K86
                  |    |--P. simulus Iwata 1952 TN03
                  |    `--P. spiralis (Coe 1930) TN03
                  `--Cephalothrix Oersted 1844 K86
                       |--C. arenaria Hylbom 1957 K86
                       |--C. atlantica Gerner 1969 K86
                       |--C. germanica Gerner 1969 K86
                       |--C. hongkongiensis CV16
                       |--C. mediterranea Gerner 1969 K86
                       `--C. pacifica Gerner 1969 K86

Nemertea incertae sedis:
  Arhynchonemertes Riser 1988 G02
    `--*A. axi Riser 1988 G02
  Carinesta tubulanoides Gibson 1990 G02
  Hirudella Münster 1842 H62
    `--*H. angusta Münster 1842 H62
  Legnodesmus Ehlers 1869 H62
    `--*L. ehlersi Howell 1958 H62
  Planolineus exsul G88
  Siolineus turbidus G88
  Apatronemertes albimaculosa G88
  Nemertes polyhopla (n. d.) G88

*Type species of generic name indicated

REFERENCES

[CV16] Cannon, J. T., B. C. Vellutini, J. Smith, III, F. Ronquist, U. Jondelius & A. Hejnol. 2016. Xenacoelomorpha is the sister group to Nephrozoa. Nature 530: 89–93.

[C03] Chernyshev, A. V. 2003. New species of the genus Hubrechtella (Nemertea, Anopla) from the Sea of Japan and validation of the family Hubrechtellidae. Russian Journal of Marine Biology 29: 333–336.

[EL11] Erwin, D. H., M. Laflamme, S. M. Tweedt, E. A. Sperling, D. Pisani & K. J. Peterson. 2011. The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334: 1091–1097.

[G02] Gibson, R. 2002. The Invertebrate Fauna of New Zealand: Nemertea (ribbon worms). NIWA Biodiversity Memoir 118. National Institute of Water and Atmospheric Research: Wellington.

[G88] Gray, J. 1988. Evolution of the freshwater ecosystem: the fossil record. Palaeogeography, Palaeoclimatology, Palaeoecology 62: 1–214.

[H62] Howell, B. F. 1962. Worms. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt W. Miscellanea: Conodonts, Conoidal Shells of Uncertain Affinities, Worms, Trace Fossils and Problematica pp. W144–W177. Geological Society of America, and University of Kansas Press.

[K86] Kirsteuer, E. 1986. Nemertina. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 72–75. E. J. Brill/Dr W. Backhuys: Leiden.

[PP15] Pisani, D., W. Pett, M. Dohrmann, R. Feuda, O. Rota-Stabelli, H. Philippe, N. Lartillot & G. Wörheide. 2015. Genomic data do not support comb jellies as the sister group to all other animals. Proceedings of the National Academy of Sciences of the USA 112 (50): 15402–15407.

[RP07] Rousset, V., F. Pleijel, G. W. Rouse, C. Erséus & M. E. Siddall. 2007. A molecular phylogeny of annelids. Cladistics 23: 41–63.

[TN03] Thollesson, M., & J. L. Norenburg. 2003. Ribbon worm relationships: a phylogeny of the phylum Nemertea. Proceedings of the Royal Society of London Series B—Biological Sciences 270: 407–415.

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