Meeting Abstract

P3.138  Monday, Jan. 6 15:30  Limb mechanics and locomotor performance during different modes of locomotion in long-limbed and short-limbed lizards SEDLAK, KA*; GERALD, GW; Nebraska Wesleyan University ksedlak@nebrwesleyan.edu

Limb reduction exhibited by many species of lizards is a relatively common phenomenon found in a number of lizard lineages. This trend seems contradictory because limbs are, intuitively, necessary for efficient locomotion in most terrestrial vertebrates. However, it has been hypothesized that smaller limbs, along with more elongated bodies, might be more advantageous for movement in some locomotor situations (such as moving underground and in water). Despite this, no study, to our knowledge, has closely examined the influence of limb length on locomotor performance and kinematics during different modes of locomotion. We quantified the relationship between limb length and various performance and kinematic variables in a short-limbed lizard (Riopa fernandi) and a long-limbed lizard (Leiolepis belliana) species during running, burrowing, and swimming. We found no influence of limb length on running speed or running kinematic variables. However, limb length was significantly related to burrowing with lizards with relatively smaller limbs exhibiting faster speeds and less interrupted stride cycles and reduced stride frequencies. Owing to the observation that the species used in this study swim very differently, limb length was positively related to swim speed in the long-limbed species only. This study provides important data on how limb length during movement in certain locomotor situations could influence selection for smaller limbs in the lineages that led to the evolution of limb-reduced lizards and snakes.