Anatomy and Embryology

, Volume 174, Issue 1, pp 15–26

Scanning microscopy of platypus teeth

  • Keith S. Lester
  • Alan Boyde
Original Articles

Summary

Anorganic unerupted developing teeth and airdired erupted teeth of the platypus (Ornithorhynchus anatinus) were examined in a scanning electron microscope and in a tandem scanning reflected light microscope. Typically mammalian developing fronts of enamel and dentine were identified in the anorganic unerupted specimens. The developing teeth were particularly small and fragile and the enamel elusive and difficult to examine in the normal way for morphological detail. Prepared fractured surfaces of unerupted specimens revealed preferentially oriented crystallite groups in the enamel generally perpendicular to the developing front and a highly globular, mineralized pattern in the dentine with fine diameter, sparsely distributed dentinal tubules.

Although optically homogeneous, the enamel of both developing and mature teeth displayed well-defined incremental lines, radial clefts, crystallite domains of variable size and outline, and fine tubules when examined by high contrast, back-scattered electron imaging. The enamel is prismatic only in part; well-formed, regular prisms not being a primary feature of platypus enamel. This can be related to the variability inherent in the developing surface and the thinness of the enamel layer. No surface was found which could be confidently identified as cementum; those developing surfaces not covered by enamel displaying small calcospherites which elsewhere marked the outer aspect of the dentine.

Key words

Enamel Dentine Tooth Platypus 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Boyde A (1984) Methodology of calcified tissue preparation for SEM. In: GR Dickson (ed) Methods of calcified tissue preparation. Elsevier, Amsterdam, pp 251–307Google Scholar
  2. Boyde A, Reith EJ (1969) Pattern of mineralization of rat molar dentine. Z Zellforsch 94: 47–68Google Scholar
  3. Boyde A, Petran M, Hadravsky M (1983) Tandem scanning reflected light microscopy of internal features in whole bone and tooth samples. J Microsc 132: 1–7Google Scholar
  4. Broom R (1935) Some points in the anatomy of the platypus mouth. S Agr J Sci 32: 322–328Google Scholar
  5. Grant T (1984) The platypus. University Press Kensington, New South Wales, pp 10–21Google Scholar
  6. Green HLHH (1937) The development and morphology of the teeth of Ornithorhynchus. Phil Trans Roy Soc Lond Ser B 288: 367–420Google Scholar
  7. Griffiths M (1978) The biology of the monotremes. Academic Press Inc., New York, pp 1–19Google Scholar
  8. Hill JP, de Beer GR (1949) Development of the monotremata. Part VII. Trans Zool Soc Lond 26: 503–544Google Scholar
  9. Lester KS, Archer M (1986) A brief description of the molar enamel of Obdurodon insignis. Anat Embryol (in press)Google Scholar
  10. Lester KS, Boyde A (1984) Scanning electron microscopy of platypus Ornithorhynchus anatinus teeth. IADR New Zealand Abstract No 39Google Scholar
  11. Moss ML (1969) Evolution of mammalian dental enamel. Am Mus Nov 2360: 1–39Google Scholar
  12. Petran M, Hadravsky M, Boyde A (1985) The tandem scanning reflected light microscope. Scanning 7: 97–108Google Scholar
  13. Poulton EB (1888a) True teeth in the young Ornithorhynchus paradoxus. Proc Roy Soc 43: 353–356Google Scholar
  14. Poulton EB (1888b) The true teeth and the horny plates of Ornithorhynchus. J Microsc Sci 29: 9–48Google Scholar
  15. Simpson GG (1929) The dentition of Ornithorhynchus as evidence of its affinities. Am Mus Nov 390: 1–15Google Scholar
  16. Stewart C (1892) On a specimen of the true teeth of Ornithorhynchus. J Microsc Sci 33: 229–231Google Scholar
  17. Strahan R (1983) ed. Complete book of Australian mammals. Angus & Robertson, Sydney, xviii-xxGoogle Scholar
  18. Thomas O (1889) On the dentition of Ornithorhynchus. Proc Roy Soc 46: 126–131Google Scholar
  19. Tomes CS (1904) A manual of dental enamel: human and comparative 6th edn. J & A Churchill, London 396:401Google Scholar
  20. Wilson JT (1894) Description (with figures) of a young specimen of Ornithorhynchus anatinus from the collection of the Australian Museum, Sydney. Proc Lin Soc NSW 9: 682–691Google Scholar
  21. Wilson JT, Hill JP (1907) Observations on tooth development in Ornithorhynchus. J Microsc Sci 51: 137–165Google Scholar
  22. Woodburne MO, Tedford RH (1975) The first tertiary monotreme from Australia. Am Mus Nov 2588: 1–11Google Scholar

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • Keith S. Lester
    • 1
    • 2
  • Alan Boyde
    • 1
    • 2
  1. 1.Westmead Hospital Dental Clinical SchoolWestmeadAustralia
  2. 2.Department of Anatomy and EmbryologyUniversity College LondonLondonUnited Kingdom

Personalised recommendations