Life above ground: ecology of Anolis fuscoauratus in the Amazon rain forest, and comparisons with its nearest relatives

Abstract

The polychrotid lizard Anolis fuscoauratus was studied at six localities in the Ecuadorian and Brazilian Amazon from 1994 to 1999. Throughout the Amazon, A. fuscoauratus occurs in forested habitats, is arboreal on tree trunks, limbs, and branches as well as vines, has a body temperature (Tb) of 28.7 ± 0.2°C (mean ± SE) while active, maintains Tb slightly above ambient temperatures, avoids direct sunlight during most of the day, and feeds primarily on a combination of orthopterans (20.62% by volume), spiders (16.7%), homopterans (10.62%), and insect larvae (10.35%). Despite detectable geographic variation in adult body size and diets, general ecological attributes are similar among populations across the Amazon region even though the number of sympatric Anolis species as well as the total number of lizard species vary among sites. Overall ecological similarity likely reflects the fact that there is little evolutionary divergence among populations. Comparisons between A. fuscoauratus and its three closest relatives, A. humilis and A. limifrons of Central America and A. trachyderma of the Amazon, reveal some similarities. All four species maintain relatively low Tb while active. Anolis fuscoauratus and A. limifrons are ecologically and morpho logically similar but A. fuscoauratus is larger. Anolis humilis and A. trachyderma are more similar to each other ecologically than they are to their respective sympatric congeners. Anolis humilis is smaller than and morphologically dissimilar to A. trachyderma. The Amazonian and Central American species pairs do not comprise each other's closest relatives, indicating that similar ecomorphs have evolved independently in the Amazonian and Central American rain forests.