Fossil vertebrates preserved in amber are rare. Although as many as a dozen lizards in amber may exist, most are in private collections (de Queiroz et al. 1998). Only two specimens of Anolis lizards preserved in Dominican amber have been described previously (Rieppel 1980, de Queiroz et al. 1998). Both descriptions are based on relatively complete skeletons retaining some soft tissue and squamation. We report here a third Anolis lizard preserved in amber with details of skull osteology and taphonomy described and illustrated using digitally reconstructed images derived from high-resolution CT data. Application of CT imaging to the study of fossils is well documented (Cifelli et al. 1996, Rowe 1996, Brochu 2000, Kobayashi et al. 2002) and has obvious advantages in illustrating internal or hidden details through non-destructive means.
The earliest comprehensive study of the osteology of Anolis lizards was conducted by Etheridge (1959), utilizing radiographs of approximately 1800 specimens, and comparisons with skeletons. Radiographs were also employed in two later studies of amber-preserved Anolis specimens (Rieppel 1980, de Queiroz et al. 1998); the latter also utilized stereo-pairs. De Queiroz et al. 1998 tentatively referred both specimens to the A. chlorocyanus species group, based on postcranial characters and scale patterns.
Because these descriptions of amber-preserved anoles were based primarily on features of external morphology and skeletal characters that could be scored using binocular microscopes and stereo-radiographs, details of internal or visually obstructed morphology could not be described. For instance, neither study was able to determine the presence or absence of a splenial, a key diagnostic character of the T-clade anoles (de Queiroz et al. 1998), which includes the A. chlorocyanus species group.