Cranial growth in the squirrel monkey (Saimiri sciureus): a quantitative analysis using three dimensional coordinate...

Area of Science:

• Primatology
• Comparative Anatomy
• Morphometrics

Background:

• Advancements in 3D data acquisition enable detailed analysis of biological specimens.
• Understanding craniofacial development is crucial for evolutionary and functional studies.

Purpose of the Study:

• To investigate craniofacial form changes during growth in squirrel monkeys (Saimiri sciureus).
• To assess sexual dimorphism in the craniofacial complex across developmental stages.

Main Methods:

• Acquired 3D coordinates of 44 homologous landmarks from 104 squirrel monkey crania.
• Utilized Euclidean distance matrix analysis (EDMA) and finite element scaling analysis (FESA).
• Sorted specimens by sex and dental age groups for comparative analysis.

Main Results:

• Both sexes exhibit overall slight cranial growth, with significant localized growth in the anterior neurocranium, basicranium, and anterior palate.
• Craniofacial form differences between sexes (sexual dimorphism) are minimal throughout development.
• The orbitonasal region, cranial base, and palate show the most pronounced sexual dimorphism.

Conclusions:

• Squirrel monkey craniofacial development is characterized by localized growth hotspots rather than uniform expansion.
• Sexual dimorphism in the squirrel monkey skull is subtle, with specific regions displaying slightly greater divergence between sexes.