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Enamel structure in odontocete whales.
1Department of Oral Anatomy, Nippon Dental University, Niigata, Japan.
Scanning Microscopy
|September 1, 1987
Summary
The enamel structure of odontocetes (toothed whales) is highly variable, with some species showing clear prisms and others lacking them entirely. This variability is likely a secondary evolutionary trait.
Area of Science:
- Zoology
- Paleontology
- Histology
Background:
- Mammalian enamel structure is well-studied, but odontocete enamel remains poorly understood.
- Odontocetes, or toothed whales, exhibit diverse dental morphologies.
Purpose of the Study:
- To investigate and describe the enamel structure of various living odontocete species.
- To compare odontocete enamel histology with other mammals and evolutionary lineages.
Main Methods:
- Histological examination of tooth enamel from 11 odontocete species across 7 families.
- Microscopic analysis to identify prism patterns, pseudoprisms, enamel tubules, and enamel thickness.
Main Results:
- Clear prism structures observed in delphinids and Pontoporia blainvillei.
- Prismless enamel found in Physeter catodon, Berardius bairdi, Phocoena phocoena, Phocoenoides dalli, and Delphinapterus leucus.
- Extreme thinness of enamel in Berardius bairdi and Delphinapterus, and absence of enamel in Monodon monoceros.
Conclusions:
- Odontocete enamel structure is highly variable, ranging from prismatic to completely prismless.
- The presence of certain enamel structures suggests retention from ancestral forms.
- This variability is interpreted as a secondary phenomenon linked to the degenerative evolutionary history of odontocete enamel.