Meeting Abstract
The evolution of novel traits is often associated with large-scale morphological changes that are reflected both externally and internally. For vertebrates, many novel traits associated with feet have emerged, and these are often related to locomotion. This is especially true for morphological changes accompanying the gecko adhesive system. Digit morphology and the arrangement of the adhesive apparatus around the foot can dictate the orientations at which a gecko can adhere. Previous research described changes in the digit morphology among gekkotans and observed trends towards symmetry within the foot that appeared to precede the evolution of the gecko adhesive system. Using a phylogenetic comparative framework, we reanalyzed the data from this study and applied geometric morphometric analysis to additional data obtained from X-Ray scans in order to examine patterns of morphological evolution in association with the gain and loss of adhesive capabilities, as well as transitions in habitat. Our sample includes at least five origins of the adhesive system, as well as several cases of secondary loss or reduction. Our results confirm that pad-bearing lineages tend to have shorter digits and larger inter-digital angles than padless lineages, and this suggests repeated shifts to a similar pad-bearing morphology. Changes in the shape of the foot in association with the adhesive system also suggest changes to proximal elements of the foot, including the bones comprising the ankle joint. These evolutionary patterns of morphological change demonstrate the hierarchal nature of the gecko adhesive system and foot morphology. Supported by NSF IOS 1147043.
