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Cranial evolution in sakis (Pithecia, Platyrrhini). II: Evolutionary processes and morphological integration
G Marroig1, M De Vivo, J M Cheverud
1Departamento de Biologia Celular e Genética, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Brasil. gmarroig@ib.usp.br
Journal of Evolutionary Biology
|March 6, 2004
Summary
Evolutionary processes in saki monkeys (Pithecia) were studied. Cranial morphology shows significant integration, with genetic drift potentially driving evolution, suggesting neutral evolution may be predominant.
Area of Science:
- Primatology
- Evolutionary Biology
- Morphometrics
Background:
- Saki monkeys (Pithecia) exhibit diverse cranial morphologies.
- Understanding the evolutionary mechanisms behind these patterns is crucial.
Purpose of the Study:
- To quantitatively describe interspecific differentiation in saki monkeys.
- To examine the evolutionary processes, including morphological integration and natural selection, shaping their cranial morphology.
Main Methods:
- Quantitative analysis of cranial morphology and interspecific differentiation.
- Comparison of species correlation matrices with expected patterns of morphological integration.
- Reconstruction of differential natural selection gradients.
Main Results:
- Significant and similar patterns of development-based cranial integration were found across saki species.
- Facial regions were more influenced by size variation than neural regions.
- Genetic drift may sufficiently explain cranial evolution, with potential contributions from natural selection.
Conclusions:
- Cranial evolution in saki monkeys appears to be significantly influenced by morphological integration.
- While natural selection may play a role, the evidence suggests that neutral evolution, possibly driven by genetic drift, might be the primary mechanism.
- The functional significance of selection gradients remains unclear, further supporting the possibility of predominantly neutral evolutionary processes.