Investigating mechanoreceptor variability and morphometric proxies in Rhesus Macaques: Implications for primate...

Area of Science:

• Primate anatomy and evolution
• Neuroscience and sensory biology
• Dermatoglyphics and biometrics

Background:

• Primate evolution is linked to enhanced manual grasping and tactile sensation.
• Specialized mechanoreceptors in glabrous skin are crucial for fine motor skills and environmental perception.
• Research on primate hand mechanoreceptors is limited by sample access and methodology.

Purpose of the Study:

• To investigate the relationship between mechanoreceptors (Meissner and Pacinian corpuscles), dermatoglyphs, and demographic factors in rhesus macaque finger pads.
• To assess the utility of dermatoglyphs as noninvasive proxies for mechanoreceptor density.
• To understand developmental effects on mechanoreceptor density and morphology.

Main Methods:

• Examined apical finger pads from 15 juvenile to adult rhesus macaques (Macaca mulatta).
• Quantified Meissner and Pacinian corpuscle density, size, and depth.
• Analyzed correlations between mechanoreceptor data, dermatoglyph features (ridge width, spacing), and demographic variables (age, sex, digit).

Main Results:

• Significant interindividual variation in mechanoreceptor densities was observed (Meissner: 11.9-43.3/mm², Pacinian: 0-4.5/mm²).
• Mechanoreceptor density decreased, while size and depth increased with age during juvenescence, stabilizing in adults.
• Meissner corpuscle density showed a significant association with dermatoglyph ridge width and spacing, with a dermatoglyph-based model accurately predicting observed densities.

Conclusions:

• Dermatoglyphs serve as a reliable, noninvasive proxy for estimating relative Meissner corpuscle density in primates.
• Developmental changes significantly impact mechanoreceptor density and morphology during primate adolescence.
• This study highlights the importance of considering age and methodological approaches in comparative primate sensory research.