8 - Regional Variation in Macaque Dermatoglyphs Mirrors Human Tactile Sensitivity Patterns

Poster Board Number: 8
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Co-authors:

Arthur Fernandes - Department of Anthropology & Archaeology - University of Calgary; Rachel Munds - Department of Anthropology & Archaeology - University of Calgary; Sam Bauman - Caribbean Primate Research Center - University of Puerto Rico; Cayo Biobank Research Unit - Department of Neuroscience - University of Pennsylvania; Michael Montague - Department of Neuroscience - University of Pennsylvania; Melween Martinez - Caribbean Primate Research Center - University of Puerto Rico; Lauren Brent - Center for Research in Animal Behaviour - University of Exeter; Noah Snyder-Mackler - Center for Evolution and Medicine and School of Life Sciences - Arizona State University; James Higham - Department of Anthropology - New York University; Amanda Melin - Department of Anthropology & Archaeology, Department of Medical Genetics, Alberta Children’s Hospital Research Institute - University of Calgary; Carrie Veilleux - Department of Anatomy, Arizona College of Osteopathic Medicine - Midwestern University

Abstract Body : There is growing evidence that dermatoglyph ridges play a role in the sense of touch in human and non-human primates. Previous work in humans and macaques suggest touch sensitivity and mechanoreceptor density in the fingertips are associated with dermatoglyph ridge features. Dermatoglyphs are also found in other glabrous (non-hairy) skin regions, including the palm and plantar foot. In humans, touch sensitivity varies considerably across these regions, and similar variation is expected for macaques based on somatosensory cortex organization patterns (e.g., hands more sensitive than feet). However, it is not clear whether dermatoglyph ridges also vary across these regions. In this project, we investigated dermatoglyphs in the glabrous skin of the hands and feet of free-ranging rhesus macaques (Macaca mulatta) at Cayo Santiago Primate Field Station in Puerto Rico. We hypothesized that the width and spacing of dermatoglyph ridges will vary across skin regions corresponding to predicted differences in touch sensitivity. We collected dermatoglyph prints non-invasively from the hands (thumb and index fingertips, palm) and feet (hallux pad, heel) of 33 individuals and quantified average ridge width and between-ridge spacing for each print. We used linear mixed models to evaluate effects of skin region on each metric, controlling for individual identity, age, sex, and body mass. We found that dermatoglyph ridges were significantly wider in all three hand regions relative to the heel, with the hallux intermediate. Between ridge spacing also varied significantly across regions, with narrowest spacing in the fingers, followed by the palm and hallux, and widest in the heel. Overall, skin regions predicted to be more sensitive to touch (fingertips, palm) had wider, more densely packed dermatoglyph ridges, while those predicted to have low sensitivity (heel) have narrow, widely spaced ridges. These findings suggest that dermatoglyphs may be a useful tool for comparative analyses of touch.









Keywords: Touch; Somatosensory System; Fingerprint; Morphometrics; Natural population