Research Training Program

Smithsonian Institution
National Museum of Natural History

PROJECT SUMMARY
1996

Jason A. Kaufman
Columbia University
New York, New York
Richard W. Thorington, Jr
Supervising Scientist
Department of Vertebrate Zoology
"Accomplishing one's own research goals is a tremendously rewarding experience, and l am so grateful that the Research Training Program provided me with this exhilarating opportunity."

Leaping and Limb Anatomy: a comparison of the hind-limb morphology in two species of tamarin (Saguinus fuscicollis and Saguinus mystax)

ABSTRACT
The study of functional morphology ultimately seeks to understand the ways in which an organism adapts to its natural environment through changes in anatomical features. An organism's behavior can place stresses on its anatomy that may result in morphological change, thus affecting the efficiency with which the organism interacts with its environment. A crucial question, however, is just how tightly an organism is bound to a specific behavior given the suite of characters with which it operates. In this study, the hind-limb morphology of two species of South American tamarin monkeys, Saguinus fuscicollis and Saguinus mystax, were examined. These two species provide an excellent opportunity for comparative functional morphology because one species, S. fuscicollis, performs more leaping than the other. The purpose of the study was to determine if there were any quantitatively significant differences between these two species with regard to their hind-limb musculature. In the process of this examination, an examination was performed on previous research done by John Fleagle of the State University of New York at Stony Brook who examined the hind-limb musculature of Malaysian langurs.

These data did, indeed, display significant differences in the musculature of S. mystax and S. fuscicollis. For example, S. fuscicollis has larger gluteal retractors than S. mystax, and these muscles probably have an important function in leaping. These results, however, did not conform with Fleagle's results, suggesting that these species are either behaving differently with regard to locomotion, or are utilizing different muscles for the same behaviors. Lastly, these results displayed intriguing data showing that the adductor muscles were larger in S. fuscicollis. It could be that this difference is due to differences in posture (vertical clinging) and not locomotion.

This research was supported by a grant from the National Science Foundation Research Experiences for Undergraduates program, Award Number DBI-9531331.

Letter of Gratitude