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Patterns of dermal denticle loss in sharks
Michael A Fath1, Greta Wong2, Chloé-Rose Colombero3,4
1Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA.
Journal of Morphology
|August 21, 2024
Summary
Sharks continuously replace lost dermal denticles, with less than 6% missing at any time. This lifelong skin surface renewal may reduce fouling and maintain shark skin function.
Area of Science:
- Ichthyology
- Developmental Biology
- Paleontology
Background:
- Shark skin is covered in dermal denticles, which are constantly lost and replaced.
- Understanding denticle dynamics is crucial for assessing skin function and interpreting fossil records.
Purpose of the Study:
- To investigate patterns of dermal denticle loss in mature sharks.
- To elucidate the process of denticle replacement in sharks.
Main Methods:
- Quantified missing denticles across body regions for two shark species.
- Compared denticle loss patterns across 16 shark species.
- Examined histological مراحل of denticle regrowth.
Main Results:
- Sharks typically miss 0%-6% of denticles across species and body regions.
- The smooth dogfish showed higher denticle loss on the nose; the common thresher shark exhibited greater loss overall.
- Denticle replacement involves crown development, mineralization, and eruption, with ongoing internal dentine deposition.
Conclusions:
- Denticle replacement is a continuous process in sharks, maintaining skin integrity.
- The low percentage of missing denticles suggests minimal impact on hydrodynamic function.
- Lifelong skin renewal may aid in reducing biofouling and repairing localized damage.
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