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The structure and composition of the teeth and grasping spines of chaetognaths

Published online by Cambridge University Press:  06 October 2009

Q. Bone ,
K. P. Ryan  and
A. L. Pulsford
Q. Bone
Affiliation:
The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB
K. P. Ryan
Affiliation:
The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB
A. L. Pulsford
Affiliation:
The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB
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Abstract

The teeth and grasping spines of Sagitta are similar in structure, both having a central pulp cavity surrounded by two electron-dense chitinous layers. The cells of the pulp cavity contain microtubules arranged along the long axis. The two chitinous tubes are separated by a less-dense zone crossed by coarse fibrils linking the two. The teeth and spines insert into less electron-dense chitin (presumably flexible) and are moved by processes of anchor cells which pass into the basal chitinous zone. The inner region of the anchor cells is apposed to the connective tissue layer on to which the muscles of the teeth and spines insert. At the base of the pulp cavity, i.e. at the secretory zone where the teeth and spines are formed, the cells of the pulp cavity contain electron-dense granules in which zinc is found; zinc is also present in the inner and outer dense chitin layers at high concentration (0·5–1·0% of the dry wt).

Both spines and teeth are tipped with fibrous cones containing silicon. It is suggested that the zinc associated with the chitin serves to toughen the teeth and spines and render them less liable to fracture, and that the silicon in the tips confers hardness to this vulnerable region.

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 63 , Issue 4 , November 1983 , pp. 929 - 939
Copyright
Copyright © Marine Biological Association of the United Kingdom 1983

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References

REFERENCES

Atkins, E. D. T., Dlugosz, J. & Foord, S., 1979. Electron diffraction and electron microscopy of crystalline α-chitin from the grasping spines of the marine worm Sagitta. International Journal of Biological Macromolecules, 1, 29–32.CrossRefGoogle Scholar
Beklemishev, K. v., 1954. Demonstration of silica parts in the integument of the lower crustaceans. Doklady¯ Akademii nauk SSSR, 97, 543–545.Google Scholar
Bryan, G. W. & Gibbs, P. E., 1979. Zinc – a major inorganic component of nereid polychaete jaws. Journal of the Marine Biological Association of the United Kingdom, 59, 969–973.CrossRefGoogle Scholar
Dilly, P. N. & Nixon, M., 1976. The cells that secrete the beaks in octopus and squids (Mollusca, Cephalopoda). Cell and Tissue Research, 167, 229–241.CrossRefGoogle ScholarPubMed
Duvert, M. & Gros, D., 1982. Further studies on the junctional complex in the intestine of Sagitta setosa. Cell and Tissue Research, 225, 663–671.CrossRefGoogle ScholarPubMed
Furnestin, M.-L., 1982. Dents et organe vestibulaire des Chaetognathes au microsope électronique à balayage. Relations taxonomiques, écologiques et biologiques. Revue zoologique africaine, 96, 138–173.Google Scholar
George, J. D. & Southward, E. C., 1973. A comparative study of the setae of Pogonophora and polychaetous Annelida. Journal of the Marine Biological Association of the United Kingdom, 53, 403–424.CrossRefGoogle Scholar
Hillerton, J. E. & Vincent, J. F. V., 1982. The specific location of zinc in insect mandibles. Journal of Experimental Biology, 101, 333–336.CrossRefGoogle Scholar
Kuhl, W., 1938. Chaetognatha. In Bronn's Klassen und Ordnungen des Tierreichs, ed 4. Vermes, Abteilung IV, Buch 2, Teil 1, pp. 1–226. Leipzig: Akademische Verlagsgesellschaft m.g.H.Google Scholar
Muzzarelli, R. A. A. & Tubertini, O. 1969. Chitin and chitosan as Chromatographie supports and adsorbents for collection of metal ions from organic and aqueous solutions and seawater. Talanta, 16, 1571–1577.CrossRefGoogle Scholar
Nagasawa, S. & Marumo, R., 1973. Structure of grasping spines of six chaetognath species observed by scanning electron microsopy. Bulletin of the Plankton Society of Japan, 19, 5–16.Google Scholar
Rudall, K. M., 1976. Molecular structure in arthropod cuticles. In The Insect Integument (ed. Hepburn, H. R.), pp. 21–41. Amsterdam: Elsevier.Google Scholar
Schmidt, W. J., 1940. Zur morphologie, Polarisationsoptik und Chemie der Griefhaken von Sagitta hexaptera. Zeitschrift für Morphologie und Ökologie der Tiere, 37, 63–82.CrossRefGoogle Scholar
Simpson, T. L. & Volcani, B. E., 1981. Introduction. In Silicon and Siliceous Structures in Biological Systems (ed. Simpson, T. L. and Volcani, B. E.), pp. 3–12. Springer-Verlag.CrossRefGoogle Scholar