SYNOPTIC DESCRIPTION OF THE PHYLUM KINORHYNCHA

EUKARYA> UNIKONTA> OPISTHOKONTA> ANIMALIA> BILATERIA> PROTOSTOMATA> ECDYSOZOA> SCALIOPHORA> KINORHYNCHA

PHYLUM KINORHYNCHA LINKS

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

I. SYNONYMS: kinorhynchs, echinoderma, spiny-crowned worms, mud-dragons.

II. NUMBER: > 100 species known.

III. PHYLUM CHARACTERISTICS:
- A. Structure
  - Symmetry: Bilateral
  - Body Cavity: Mostly acoelomic with small pseudocoelomic spaces.
  - Body Covering: Covered by chitinous cuticle that is divided into dorsal (tergites) and ventral (sternites) articulating plates. This is shed as the animal grows in the early stages of development.
  - Support: Hydrostatic skeleton with external cuticle. Body divided into 11 segments.
  - Digestive System: Complete food tube with mouth (muscular pharynx) and anus.
  - Circulatory System: Absent.
  - Locomotion: Anterior segments telescope. Anterior mouth cone (introvert) covered with spines (scalids) which grip sediment and help to “pull” the animal as it extends and retracts its head segment.
  - Excretory System: Protonephridial excretory canals.
  - Nervous System: Multi-lobed “brain”. Nerve cords run ventrally with ganglia in the body segments. Sensory bristles, photoreceptors (in some).
  - Endocrine System: None.
- B. Reproduction:
  - Reproductive System: Sexes separate. Oviparous.
  - Development: Not known.
- C. Ecology: Benthic marine.

LITERATURE CITED

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.

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.

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

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.

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

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.

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

SYNOPTIC DESCRIPTION OF THE PHYLUM KINORHYNCHA

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