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Evolution, development, and regeneration of tooth-like epithelial appendages in sharks
Ella F Nicklin1, Karly E Cohen2, Rory L Cooper3
1Department of Biology, University of Florida, Gainesville, USA.
Developmental Biology
|August 18, 2024
Summary
Sharks possess unique skin denticles, which are tooth-like structures. This study explores the shared origins and distinct regenerative properties of skin denticles and oral teeth in sharks.
Area of Science:
- * Evolutionary developmental biology
- * Comparative anatomy and histology
- * Shark biology and paleontology
Background:
- * Sharks and related species feature dermal denticles, specialized skin appendages resembling teeth.
- * These dermal denticles (odontodes) share morphological and genetic similarities with oral teeth.
- * Understanding the relationship between skin and oral odontodes is crucial for evolutionary studies.
Purpose of the Study:
- * To identify unifying characteristics of all shark odontodes (teeth and dermal denticles).
- * To differentiate between skin and oral odontodes based on their renewal capacities.
- * To investigate the developmental and genetic factors distinguishing these structures.
Main Methods:
- * Histological and morphological analysis of embryonic shark tissues.
- * Comparative review of existing data on shark dermal denticles and oral teeth.
- * Examination of regenerative processes in selected chondrichthyan models, including Scyliorhinus canicula.
Main Results:
- * Identification of shared developmental and genetic signatures between oral teeth and dermal denticles.
- * Distinct differences in renewal mechanisms observed between skin and oral odontodes.
- * Insights into the molecular and morphological definitions of a 'tooth' in sharks.
Conclusions:
- * Shark skin denticles and oral teeth originate from common developmental pathways.
- * Variations in regenerative capacity highlight functional divergence despite shared ancestry.
- * This research provides a foundation for understanding odontode evolution and diversity.
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