Meeting Abstract
Ecology broadly correlates with morphology, climate, and environment in extant reptiles. But how specific variables correlate with ecology, particularly against changing climatic conditions through time, has not yet been tested. In this study, I ask whether specific features of extinct lizards and their environments are correlated with known associations in extant lizards of morphological traits, climate, habitat, and dietary and thermal ecology. I investigated the fossil record of North American anguid lizards, which were abundant through the Paleogene in the Western Interior basins. This group includes large forms (skull length ≤ 125 mm), with unknown ecological affinities, restricted to the Eocene. In a prior study, I estimated snout-vent length (SVL) from skull material for large Eocene anguids using extant analogous taxa, and found that anguid body size changes track climatic changes through the Eocene. For this study, I surveyed all extant lizard clades for suitable ecological analogues to large Eocene anguids based on morphological variables, including body size and dentition, as well as climatic and environmental context known from other proxies. Xenosaurus and Heloderma (Anguimorpha) scored highest for similarity in morphology and environmental context to large Eocene anguids. These results suggest that these lizards were saxicolous, thermoconforming insectivores living in closed tropical forests in the early Eocene. Late Eocene anguids were also insectivorous, but their thermal ecology remains unclear. Future work will integrate independent lines of evidence from the environmental context of cooling and aridification in the late Eocene to test for factors that contributed to the decline of large-bodied anguids by the Oligocene.
