Ecomorphology and locomotion of Sceloporus

GALLARDO, L.I.*; NISHIKAWA, K.C.: Ecomorphology and locomotion of Sceloporus

Comparative analyses of iguanian lizard morphology have shown that certain body proportions are consistently associated with particular microhabitats. This result suggests that a single genus with ecologically diverse species will exhibit morphological variation reflecting their ecological niches. Morphological measurements were taken from species of Sceloporus of varied microhabitat specialization, ranging from ground dwellers to saxicolous species. Saxicolous species, which regularly encounter incline in their habitat are expected to exhibit a lower length ratio between the most distal and proximal joints than ground-dwelling species. Saxicolous species are also expected to have proportionally shorter hind limbs when compared to those of ground dwellers. Likewise, locomotor kinematics and performance variables are expected to correlate with ecological niche and morphology. Prior studies have found that species of different body proportions exhibit changes in locomotor kinematics on flat versus inclined substrates. In this study, species of Sceloporus of varied ecomorphologies were recorded running on horizontal and inclined surfaces to determine how the type of terrain an animal inhabits affects locomotion. High-speed imaging of lizards running on a treadmill and a stationary track assessed how incline affects kinematics, acceleration and velocity. Ground-dwelling species on an incline are expected to alter limb posture and stride kinematics to a greater extent than saxicolous species and to exhibit a reduction in locomotor performance.

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