Meeting Abstract

2.4  Wednesday, Jan. 4  How fore- and hindlimb function changes with incline and perch diameter in Anolis carolinensis FOSTER, K.L.*; HIGHAM, T.E.; Univ. of California, Riverside; Univ. of California, Riverside

Arboreal lizards often traverse a wide range of inclines and surface diameters in their habitats. To execute these complex locomotor behaviors, both the fore- and hindlimbs are likely important. However, few studies have examined the role of the forelimbs in lizard locomotion. To assess whether the fore- and hindlimbs of lizards respond similarly to changes in incline and perch diameter, we obtained three dimensional high speed video of 4 adult male green anoles (Anolis carolinensis) running on flat (9cm wide) and small, round (1.3cm diameter) perches inclined at 0o, 45o, and 90o. Overall, the forelimb extended and retracted faster through stance than the hindlimb, while initial flexion at footfall was faster in the hindlimb. Proximal joint angles of both limbs were more affected by perch diameter changes than distal joints, although the humerus and femur exhibited opposite trends. In contrast, the distal joints were more affected by incline than perch diameter. A greater number of variables were significantly affected by surface diameter than by incline and for the majority of those that showed trends with incline, the 45o treatment on the small perch was significantly different from the level and vertical. At all inclines, the manus were placed on the dorsal surface of small perches with the pes placed dorso-laterally, suggesting differences in the propulsive mechanisms and contributions between the forelimb and hindlimb. We not only show a differential response to habitat challenges between fore- and hindlimbs, but we suggest that the forelimb plays an important role in propelling arboreal anoles under certain circumstances. The next step is to investigate the physiological mechanisms underlying these functional differences between limbs in relation to habitat structure.