Evolutionary trade-offs in locomotor capacities in lacertid lizards: are splendid sprinters clumsy climbers?

We tested the hypothesis that an evolutionary trade-off exists between the capacity to run on level terrain and the ability to climb inclined structur es in lacertid lizards. Biomechanical and physiological models of lizard lo comotor performance suggest that the morphological design requirements of a ground-dwelling vs. scansorial life style are difficult to reconcile. This conflict is thought to preclude simultaneous evolution of maximal locomoto r performance on level and inclined terrain. This notion has been corrobora ted by comparative studies on lizard species from other groups (Anolis, Cha maeleo, Sceloporus), but is not supported by our data on 13 species from th e family Lacertidae. We found no indication of a negative association betwe en maximal sprint speed of lizards over a level racetrack (indicative of gr ound-dwelling locomotor performance), on an inclined stony surface (indicat ive of climbing performance over rock faces) and inclined mesh surface (ind icative of clambering performance among vegetation). Moreover, morphologica l characteristics associated with fast sprinting capacities (e.g. long hind limbs) apparently enhance, rather than hinder climbing and clambering perf ormance. We conclude that in our sample of lacertid lizards, the evolution of fast sprinting capacity on level terrain has not inflicted major restric tions on climbing and clambering performance.