SYNOPTIC DESCRIPTION OF THE PHYLUM NEMATODA

EUKARYA> UNIKONTA> OPISTHOKONTA> ANIMALIA> BILATERIA> PROTOSTOMATA> ECDYSOZOA> NEMATOIDA> NEMATODA

PHYLUM NEMATODA LINKS

The following information came from Margulis and Schwartz (1998), Buchsbaum (1938), Barnes (1980), Barnes (1984), Brusca and Brusca (2003), Hickman (1973), Nielsen (2001), Storer and Usinger (1965), and Tudge (2000).

I. SYNONYMS: round worms, nematodes, Nemata.

II. NUMBER: > 15,000 species known; perhaps more than 1,000,000 actual species.

III. PHYLUM CHARACTERISTICS:
- A. Structure
  - Symmetry: Bilateral
  - Body Cavity: Well-defined and large pseudocoelom.
  - Body Covering: Complex cuticular layers (usually of collagen (text with tooltip) ); no superficial annulations.
  - Support: Hydrostatic skeleton.
  - Digestive System: Complete food tube with terminal mouth and subterminal anus.
  - Circulatory System: Absent.
  - Locomotion: Longitudinal muscles (no circular) underlie cuticle (text with tooltip) . Move with characteristic s-shaped movements.
  - Excretory System: When present, in form of renette cells that discharge anterior-ventrally.
  - Nervous System: Anterior nerve ring and ventral double, ganglionated nerve cord.
  - Endocrine System: None.
- B. Reproduction:
  - Reproductive System: Most are dioecious (text with tooltip) . Fertilization internal. Some are parthenogenic.
  - Development: Zygote develops by determinate, but not spiral cleavage. Direct development.
    - Life Cycles of
      - Trichinella
      - Ascaris
      - Necator
      - Dracunculus
      - Brugia
      - Enterobius
- C. Ecology: Free-living and parasitic in plants and animals. Terrestrial and aquatic. They are present in nearly all known habitats.

LITERATURE CITED

Aguinaldo, A. M. A., J. M. Turbeville, L. S. Linford, M. C. Rivera, J. R. Garey, R. A. Raff, and J. A. Lake. 1997. Evidence for a clade of nematodes, arthropods and other moulting animals. Nature. 387:489-493.

Barnes, R. D. 1980. Invertebrate Zoology. Saunders College/Holt, Rinehart and Wilson, Philadelphia.

Barnes. R. S. K. 1984a. Kingdom Animalia. IN: R. S. K. Barnes, ed. A Synoptic Classification of Living Organisms. Sinauer Associates, Inc., Sunderland, MA. pp. 129-257.

Blaxter, M. L., P. De Ley, J. R. Garey, L. X. Lie, P. Scheldeman, A. Vierstraete, J. R. Vanfleteren, L. Y. Mackey, M. Dorris, L. M. Frisse, J. T. Vida, and W. K. Thomas. 1998. Nature. 392: 71-75.

Brusca, R. C. and G. J. Brusca. 2003. Invertebrates. Sinauer Associates, Inc. Sunderland, Mass.

Buchsbaum, R. 1938. Animals Without Backbones, An Introduction to the Invertebrates. The University of Chicago Press. Chicago.

Dorris, M., P. De Ley, and M. L. Blaxter. 1999. Molecular analysis of nematode diversity and the evolution of parasitism. Parasitology Today. 15(5): 188-193.

Giribet, G., C. W. Dunn, G. D. Edgecombe, and G. W. Rouse. 2007. A modern look at the Animal Tree of Life. Zootaxa. 1668: 61-79.

Hickman, C. P. 1973. Biology of the Invertebrates. The C. V. Mosby Company. Saint Louis.

Lartillot, N. and H. Philippe 2008. Improvement of molecular phylogenetic inference and the phylogeny of Bilateria. Phil. Trans. R. Soc. B. 363: 1463-1472.

Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Company. New York.

Nicholas, W.L. 2001b. The pseudocoelomate Ecdysozoa. In: Anderson, D.T., ed. Invertebrate Zoology. Oxford University Press. Oxford, UK. pp. 98-119.

Nielsen, C. 2001. Animal Evolution: Interrelationships of the Living Phyla. 2nd Edition. Oxford University Press. Oxford. [L]

Noble, E. R. and G. A. Noble. 1976. Parasitology, The Biology of Animal Parasites. 4th edition. Lea and Febiger. Philadelphia.

Pechenik, J. A. 2005. Biology of the Invertebrates. McGraw-Hill. New York.Schmidt-Rhaesa, A. 1998. Phylogenetic relationships of the Nematomorpha – a discussion of current hypotheses. Zoologischer Anzeiger 236:203-216.

Philip, G. K., C. J. Creevey, and J. O, McInerney. 2005. The opisthokonta and ecdysozoa may not be clades: stronger support for the grouping of plant and animal than for animal and fungi and stronger support for the coelomata than edysozoa. Molecular Biology and Evolution. 22(5):1175-1184.

Philippe, H., N. Lartillot, and H. Brinkman. 2005. Multigene analyses of bilaterian animals corroborate the monophyly of Ecdysozoa, Lophotrochozoa, and Protostomia. Mol. Biol. Evol. 22: 1246-1253.

Schmidt-Rhaesa, A. 1998. Phylogenetic relationships of the Nematomorpha – a discussion of current hypotheses. Zoologischer Anzeiger 236:203-216.

Storer, T. I. and R. L. Usinger. 1965. General Zoology. 4th Edition. McGraw-Hill Book Company. New York.

Telford, M. J. S. J. Bourlat, A. Economou, D. Papillion, and O. Rota-Stabelli. 2008. The evolution of Ecdysozoa. Phil. Trans. R. Soc. B. 363: 1529-1537.

Tudge, C. 2000. The Variety of Life, A Survey and a Celebration of all the Creatures That Have Ever Lived. Oxford University Press. New York.

Webster, B. L., R. R. Copley, R. A. Jenner, J. A. Makenzie-Dodds, S. J. Bourlat, O. Rota-Stabelli, D. T. J. Littlewood, and M. J. Telford. 2006. Mitogenomics and phylogenomics reveal priapulid worms as extant models of the ancestral Ecdysozoan. Evol. Dev. 8: 502-510.

By Jack R. Holt and Carlos A. Iudica. Last revised: 02/03/2013

SYNOPTIC DESCRIPTION OF THE PHYLUM NEMATODA

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