The goal of this research is to examine the variation in morphology of the soft tissue surfaces of the hands of prosimian primates. These morphologies will be compared with locomotion, diets, body size, etc. in these animals to understand relationships between finger composition and adaptations. The histological data collected as part of this study will be made freely available to other researchers. Since many of the subject primate species are endangered in the wild, creating a comprehensive database of primate skin samples that investigators may access, add to, and utilize as part of their own research will reduce the need for further sampling of this limited resource. This research also promotes training and education of the co-principal investigator.
The soft tissue surfaces of a primate's hands and feet are its primary interface with the environment during both locomotion and tactile exploration. As such, the variation observed in the morphology of these volar surfaces in different primates likely reflects functional variation in the nature of this interaction. In particular, the fat pads within volar surfaces are thought to assist in attenuating reaction forces generated during locomotion, and to act as a viscoelastic structures increasing the coefficient of friction between the pads and substrate. In addition, since the density and arrangement of tactile sensory receptors within volar skin can be related to over-all tactile sensitivity, it has been suggested that variation in these characteristics can be related to differences in diet and substrate preferences. Nonetheless, despite intuitive links between morphology and behavior, there has been little formal analysis demonstrating connections between particular aspects of volar skin, pads and tactile organs and specific functional attributes. The overarching goal of this dissertation research is to explore the functional correlates of variation in morphological characteristics of the volar surfaces in a select group of prosimian primates. The size and shape of the volar pads will be assessed using 3D morphometric analysis, and tactile organs within volar skin will be investigated using histological staining and stereo-light microscopy. Once described, proposed relationships of the volar morphology to dietary preferences, locomotor regimes, substrate use, body size, and bony morphology will be explored.
This Doctoral Dissertation Research Improvement award will provide support to enable a promising student to establish a strong independent research career.
This project has provided the first quantitative analysis of volar structures in prosimian primates. For the first time, dimensions of volar pads of the hands and feet have been investigated and related to the animals locomotor habits, diet, and relationships to other primates. In addition, the arrangement and densities of microstructures - including the two most easily accessible and commonly studied nerve endings - in the volar skin, which until now had been only qualitatively described, have been quantified to provide insights into tactile acuity in prosimian primates. These descriptions are therefore useful not only to the field of anthropology, but to the greater sutdy of neurology as well. In addition to scientific findings, this project has also had great implications for the advancement of women in science and medicine. The funding provided here by NSF has supported the dissertation work of a female graduate student and further assisted a female undergraduate student in expanding her skill set before entering medical school. Upon completion of their courses of study, both women will be able to apply the skills learned during the course of this project in their future careers, whether they include teaching, laboratory research, or acting as a health professional.