My research focuses on the functional morphology and evolution of primate locomotor adaptations.
I have particular interest and expertise in the functional morphology and evolution of the vertebral musculoskeletal system in primates, and the biomechanics, ontogeny and evolution of primate quadrupedal locomotion. See my CV for relevant publications.
Collaborative Proposal: Kinematics of Quadrupedal Locomotion in Free-Ranging Primates: A Comparative Functional and Phylogenetic Analysis
(Liza Shapiro, Jesse Young PIs, Tobin Hieronymous, Co-PI)
Supported by NSF BCS1640453 and BCS1640552
The broad goal of this research is to generate new information on the mechanics of quadrupedalism (movement on four limbs) in wild primates moving in their natural environments, permitting a deeper understanding of primate arboreal athleticism. Most of our knowledge about primate quadrupedal mechanics has come from lab-based research in which captive primates move across simulated branches. In this study, we will bring lab-based methods to the field. Until recently, field-based biomechanical studies have been hindered by the difficulties of bringing laboratory equipment into complex and unpredictable outdoor environments. Fortunately, video technologies have become sufficiently durable and advanced to now permit high-resolution measures of animal locomotion to be collected in the wild with unprecedented precision. In this study, we will use these techniques to analyze quadrupedal movement (as well as substrate characteristics) in ten free-ranging New World monkey species at the Tiputini Biodiversity Station in Ecuador. The results of this project will further our understanding of primate locomotor adaptation and evolution, as well as contribute to K-12 STEM education and public outreach.
The influence of very small body size on the evolution of primate quadrupedal locomotion
(In collaboration with Jesse Young)
Supported by NSF BCS 0647402, Liza Shapiro PI
Current consensus states that primate quadrupedal features are a biomechanical complex that gave early primates exclusive access to resources available in an arboreal “fine branch niche,” by providing mechanisms for balance on small and unstable branches. Most current research on primate origins indicates that ancestral primates may have been very small, perhaps as small as 10-15g, yet few studies have considered the effects of body sizes of 100g or less on primate quadrupedalism. This project uses locomotor growth and development as a means to investigate the influence of very small body size on primate locomotor evolution. The project takes a broad comparative perspective, comparing locomotion in mouse lemurs, (Microcebus murinus), the smallest living primates, to two similarly sized marsupials, sugar gliders (Petaurus breviceps) and gray short-tailed opossums (Monodelphis domestica). The comparative approach provides insight on the evolution of primate quadrupedalism by directly addressing the unique means by which small primates and other mammals navigate arboreal substrates.
Publications from this project:
2014 Shapiro, L.J., Young, J.W. and Vandeberg, J.L. Body size and the small branch niche: Using marsupial ontogeny to model primate locomotor evolution. Journal of Human Evolution. 68:14-31.
2012 Shapiro, L.J., and Young, J.W. Kinematics of quadrupedal locomotion in sugar gliders (Petaurus breviceps): Effects of age and substrate size. Journal of Experimental Biology. 215:480-496.
2010 Shapiro, L.J., and Young, J.W. Is primate-like quadrupedalism necessary for fine-branch locomotion? A test using sugar gliders (Petaurus breviceps). Journal of Human Evolution. 58: 309-319.
Research on quadrupedal walking in humans
2014 Shapiro, L.J., Cole, W.G., Young, J.W., Raichlen, D.A., Robinson, S.R., and Adolph, K.E. Human quadrupeds, primate quadrupedalism, and Uner Tan Syndrome. PLoS ONE 9 (7): e101758. Shapiro et al. 2014
Since 2005, an extensive literature documents individuals from several families afflicted with “Uner Tan Syndrome (UTS),” a condition that in its most extreme form is characterized by cerebellar hypoplasia, loss of balance and coordination, impaired cognitive abilities, and habitual quadrupedal gait on hands and feet. Some researchers have interpreted habitual use of quadrupedalism by these individuals from an evolutionary perspective, suggesting that it represents an atavistic expression of our quadrupedal primate ancestry or ‘‘devolution.’’ In support of this idea, individuals with ‘‘UTS’’ are said to use diagonal sequence quadrupedalism, a type of quadrupedal gait that distinguishes primates from most other mammals. Although the use of primate-like quadrupedal gait in humans would not be sufficient to support the conclusion of evolutionary ‘‘reversal,’’no quantitative gait analyses were presented to support this claim. Using standard gait analysis of 518 quadrupedal strides from video sequences of individuals with ‘‘UTS’’, we found that these humans almost exclusively used lateral sequence–not diagonal sequence–quadrupedal gaits. In fact, the quadrupedalism exhibited by individuals with UTS resembles that of healthy adult humans asked to walk quadrupedally in an experimental setting. We conclude that quadrupedalism in healthy adults or those with a physical disability can be using biomechanical principles rather than evolutionary assumptions.