Meeting Abstract
P1.86 Sunday, Jan. 4 How the development and microstructure of toe pad morphology reflect habitat specialization in Anolis lizards ST. LOUIS, J*; SANGER, TJ; HSIEH, T; Harvard Univeristy; Harvard University; University of Florida tsanger@oeb.harvard.edu
Squamate lizards have repeatedly evolved specialized adhesive toe pads (lamellae) which provide superior clinging ability to the groups that posses them. The extraordinary adhesive properties of these toe pads are due to microscopic setae found covering each lamellar scale. While variation is known to exist in toe pad morphology among different groups of lizards, it is unclear whether this variation has functional consequences to lizards living in different habitats. It is also unknown when in development toe pad structures arise, raising additional questions regarding the performance capabilities of juvenile lizards. Anolis lizards provide the rare opportunity to examine both of these questions on a diverse radiation of lizards inhabiting different arboreal microhabitats. Anolis habitat specialists occupying different islands but similar environments exhibit remarkable morphological similarity. For example, species that live higher in the canopy typically have larger toe pads comprised of more lamellae compared to species living low in the canopy or on the ground. In this study we have compared the microstructure of approximately 20 Anolis species occupying different microhabitats using scanning electron microscopy. Toe pads were dissected into thirds using a fine scalpel to quantify setal morphology and density. A preliminary analysis of approximately 200 micrographs indicates that several species living high in the canopy have more complex setal architecture than their ground-dwelling relatives. We have also established breeding colonies for two species, A. sagrei and A. carolinensis, to examine toe pad embryology. We found that variation in lamellae number arises at the earliest stages of toe pad development, potentially during toe pad patterning, but that setal variation does not appear to arise until at or slightly after hatching.
