Sprint performance in the lizards Gallotia simonyi and Gallotia stehlini (Lacertidae): Implications for species management

We studied the thermal sensitivity of sprint speed in the captive populatio n of the endangered lizard Gallotia simonyi (Lacertidae) on El Hierro islan d and in C. stehlini, an abundant, large-sized lizard from the nearby islan d of Gran Canaria (Canary Islands, Spain). Among adults, lizards of both sp ecies were faster than adults of other lacertids. The sprint performance cu rves for both species had a flat upper plateau, and the obtained values for performance breadth were high, indicating that species attained near maxim um sprint speeds over a wide range of body temperatures. Gallotia stehlini was significantly faster than G. simonyi both in absolute (cm/s) and relati ve speed (SVL/s). Juveniles of G, simonyi were significantly slower than ju veniles of G. stehlini only in absolute speed. The lower sprint speed of G. simonyi is consistent with the hypothesis that higher vulnerability. of th is species to introduced predators may have played a role in its near extin ction. Juveniles rather than adults from the captive population of G. simon yi should be used for reintroduction to establish wild populations, because the sprint performance of adults may have been compromised by prolonged ca ptivity.