Anatomical basis of differences in locomotor behavior in **Anolis** lizards: a comparison between two ecomorphs
Faculty of Sciences. Biology
Bulletin of the Museum of Comparative Zoology / Harvard College. Museum of Comparative Zoology. - Cambridge, Mass.
, p. 213-238
University of Antwerp
Anolis lizards have become model organisms for the study of adaptive radiation, as on each of the larger islands in the Caribbean, animals with similar morphologies have independently radiated into similar ecological niches. Central in the study of these animals have been the investigations correlating differences in limb dimensions to substrate characteristics and locomotor performance. However, little is known about differences in the musculoskeletal system that could underlie the observed differences in performance or locomotor style (i.e., gait characteristics). Here, we provide data on the morphology of the appendicular skeleton and musculature in two species of Anolis that differ greatly in habitat use and locomotor performance: A. sagrei and A. valencienni. The first and principal objective was to provide a detailed description of the appendicular morphology that could serve as a basis for further study. Our second objective was to test for quantitative differences in muscle mass and muscle mass distribution between the two species. Finally, we explore how the observed differences in the musculoskeletal system might be correlated with locomotor performance and locomotor style by analyzing data on the spatiotemporal gait characteristics in these two species while they were moving on substrates of different diameters. Our data show distinct differences in the morphology, muscle mass, and muscle mass distribution and illustrate how these may result in greater step and stride lengths in A. sagrei, allowing it to achieve higher sprint speeds. Anolis valencienni has less robust muscles that might constrain step and stride length, which in turn could provide it with greater stability on narrow substrates.