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Developmental constraints and the evolution of vertebrate digit patterns
Journal of Theoretical Biology
|October 7, 1983
Summary
Developmental constraints significantly shape vertebrate limb evolution, with most digit patterns adhering to the polar coordinate model. Differential growth explains rare exceptions in skeletal morphology.
Area of Science:
- Evolutionary biology
- Developmental biology
- Comparative anatomy
Background:
- Vertebrate limb development exhibits diverse skeletal patterns.
- Understanding the evolutionary pressures on digit formation is crucial.
Purpose of the Study:
- To analyze tetrapod digit skeletal patterns.
- To investigate the role of developmental constraints in digit pattern evolution.
- To assess the applicability of the polar coordinate model.
Main Methods:
- Analysis of skeletal morphology of 145 hands and feet from four tetrapod vertebrate classes.
- Comparison of observed digit patterns with predictions from the polar coordinate model.
Main Results:
- Developmental constraints are highly influential in vertebrate digit pattern evolution.
- 98% of analyzed patterns fit the Stock & Bryant (1981) polar coordinate model.
- Three cases of 'forbidden' morphology were observed.
Conclusions:
- The polar coordinate model effectively explains the formation and regulation of vertebrate digit patterns.
- Differential growth during development accounts for rare, atypical digit morphologies.
- Developmental constraints are a primary driver in the evolution of tetrapod limb skeletal diversity.
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