Date of Award
Dr. Christopher Anderson
Dr. Andrea Liebl
Dr. Jacob Kerby
chameleon, forelimb, chameleon anatomy
Skeletal anatomy can vary greatly among individuals of the same family that share a common ancestor. Differences in skeletal anatomy and morphology allow species to be better suited to their environments. The study of skeletal anatomy variation as it pertains to species relatedness and habitat variation can provide useful insight into what may be driving evolutionary patterns among species. Specifically, studying skeletal anatomy of the forelimb could allow for better understanding of how the forelimb anatomy differs based on the arboreality of the species, which allows for better understanding of how habitat can affect morphology. To study the skeletal structure of the forelimb, I used micro computed tomography scans (microCT scans) of various chameleon species to isolate and analyze the skeletal anatomy of the chameleon forelimb. A total of 12 species from 6 genera were used in this analysis and include species with varying levels of arboreality. Measurements of the proximal, medial, and distal widths of the radius, ulna, and metacarpals 1-5, along with the angle of curvature for the radius and the ulna, were taken and analyzed using a principal component analysis (PCA) and phylogenetic logistic regression.
Surprisingly, there was no difference between any of the forelimb measurements based on arboreality, either with or without phylogeny. However, qualitative observations of the metacarpals of the forelimb revealed a pattern based on arboreality. All arboreal species had some separation between metacarpals 1-3, whereas terrestrial species had none. The pattern shown in the metacarpals based on arboreality reveal that there seems to be a difference between chameleon forelimbs based on arboreality.
Schley, Ellie M., "Ecological and Evolutionary Drivers of Chameleon Forelimb Variation" (2023). Honors Thesis. 302.