ECOLOGY OF WHIPTAIL LIZARDS (CNEMIDOPHORUS) IN THE AMAZON REGION OF BRAZIL

We compared microhabitat use, morphology, diets, and reproduction in t hree pop ulations of Cnemidophorus lemniscatus (Alter do Chao, Curua-U na, and Roraima) and one population of C. cryptus (Rio Xingu) in the A mazon region of Brazil. Cnemidophorus lemniscatus were most common in grasslands or other open areas, but C. cryptus was restricted to sandy beach. A greater percentage of C. cryptus than C. lemniscatus were ob served foraging. Morphologically, C. lemniscatus populations were iden tical. Females of C. cryptus (all-female species) were larger than fem ales of C. lemniscatus. Based on numerical occurrence of prey, diets o f C. lemniscatus from Alter do Chao and Curua-Una were more specialize d than those for C. lemniscatus from Lavrado or C. cryptus from the Ri o Xingu. Based on volumetric occurrence of prey, C. lemniscatus from A lter do Chao were most specialized, feeding-primarily on fruits of one plant species. Also based on volumetric data, diet of C. lemniscatus from Curua-Una was most similar to that of C. cryptus. Lizards from Al ter do Chao and Curua-Una ate larger prey than did those from the othe r two sites. Concordantly, lizards in these two populations ate fewer prey. Clutch size varied from one to four eggs in C. lemniscatus and f rom one to two eggs in C. cryptus,, and there was a significant relati onship between female size and clutch size. Ecological variation exist s among populations of Amazonian Cnemidophorus. Overall, there were no ecological differences that could not be explained simply on the basi s of habitat or resource differences among localities.