Date of Award

Spring 5-6-2023

Document Type

Honors Thesis



First Advisor

Christopher Anderson, Ph.D.

Second Advisor

Saige Kelmelis, Ph.D.

Third Advisor

Andrea Liebl, Ph.D.


Chameleon, Pelvic Girdle, Arboreality, Phylogeny

Subject Categories



Morphological adaptations have allowed animals to inhabit different landscapes such as mountains, forests, plains, etc. These adaptations have increase in prevalence through natural selection processes in all species which allow favorable traits to be passed to offspring. Chameleons have evolved a plethora of adaptations that have allowed them to persist in different niches. One anatomical feature of chameleons that has not been well studied is the pelvic girdle. The pelvic girdle bridges the axial and appendicular skeletons in animals, so the size, shape, and orientation of the girdle is important to how the animal functions in its environment. The pelvic girdle was isolated from microcomputed tomography (µCT) scans from a larger chameleon µCT scan database in the Anderson Lab at the University of South Dakota. After being isolated, the pelvic girdle could then be reconstructed and visualized in 3D. This allowed lengths, widths, and spaces to be measured as well as angles between the different pelvic girdle bones. The pelvic girdles of twenty-two species across all twelve genera of chameleons were isolated and their morphology quantified. These variables were tested against a established arboreality categorizations for each species to determine the effect relative arboreality has on the pelvic girdle’s shape. This relationship was tested with and without taking phylogeny into account to determine the effects of evolutionary history on the pelvic girdle shape. These data indicate that chameleon pelvic girdles have differentiated to give arboreal or terrestrial species greater advantages in each respective environment.

Included in

Evolution Commons



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