EXPRESSIONAL DIFFERENCES BETWEEN THE SIZES OF MORPHOLOGICAL FEATURES IN URBAN AND NON-URBAN HERPETOFAUNA AROUND PHOENIX, ARIZONA

The Phoenix metro area has become increasingly more urbanized over the past few decades, changing the pressures on native lizards to navigate these novel environments. Due to effects such as the Urban Heat Island, decreased vegetation cover, increased temperatures, and general changes in substrate types between environments, urban lizards have a variety of unique environmental pressures acting on them compared to their traditional habitats. In this study, I examined various morphological features in the common side-blotched lizard (Uta stansburiana) and the ornate tree lizard (Urosaurus ornatus) to determine if these novel pressures in urban environments have significantly changed the phenotypic expression of these features as compared to a non-urban environment. The morphological features examined were weight, head length and width, femur, tibia, foot, and toe length, arm, forearm, hand, and finger length, and snout-vent (SVL), tail, and total length, along with various proportional comparisons between related traits. I hypothesized that both common side-blotched lizards and ornate tree lizards would see an increase in mass and snout-vent length, an increase in tail length, and increase in head thickness, and a decrease in limb length in urban environments as compared non-urban environments. It was found that in common-side blotched lizards, while urban individuals tended to be larger in terms of length and mass, their heads tended to be proportionally shorter and thinner than non-urban individuals. In ornate tree-lizards, non-urban individuals were larger in every regard other than SVL. Both species saw a decrease in relative limb length in comparison to body length in urban environments. The trends observed in common-side blotched lizards may be explained by higher urban temperatures and novel substrates, while the trends observed in ornate tree lizards are likely due to prey availability, hunting strategy, and novel substrates.