Meeting Abstract
Keels are raised structures or ridges that are found on the scales of many squamate taxa. Morphological examinations have noted keels in species descriptions for centuries, and it is well known that there is variation in keel structure and number across different squamate lineages adapted to different environments, especially taxa associated with swimming and semiaquatic habitats. Although the presence of these keels is well documented, the functionality of keels remains poorly known for the majority of squamates. In this study we assess the functionality of scale keels in snakes using flow visualization methods. We first microCT scanned 15 snakes with smooth and keeled scales from different habitats (e.g., terrestrial, aquatic) and 3D printed the CT scans. The 3D models were then placed in a flow tank for volumetric particle image velocimetry analysis (3D PIV). The results of these analyses suggest that keels accelerate water flow around scales and may help to reduce drag. Three dimensional surface topologies were visualized using Gelsight and show a diversity of overall surface microstructure and keel structure in snakes that live in different habitats. Future research will examine the microstructure of keeled and smooth scales in terrestrial and aquatic taxa to better understand the functionality of keels on reptiles in non-aquatic environments. This project represents the first study that investigates the function of keels and expands our knowledge on the evolutionary adaptations of squamates.
