Biogeography of early Mesozoic continental tetrapods: patterns and implications

Abstract

The stratigraphic framework for Triassic and Early Jurassic continental strata has greatly changed in recent years. These revised correlations necessitate a review of traditional views of early Mesozoic continental faunal succession and biogeography. We have examined the relationship between tetrapod distribution and paleogeographic context during the Triassic and Early Jurassic on the basis of a data base comprising updated faunal lists for major early Mesozoic assemblages of continental tetrapods. Analysis of these data supports the hypothesis that there were few barriers to biotic interchange among continental tetrapods throughout the Triassic and Early Jurassic. Early Mesozoic tetrapod assemblages are dominated by widely distributed, often cosmopolitan families. Late Triassic patterns of latitudinal variation among tetrapod assemblages appear to be correlated to those seen among terrestrial plants and contrast with the extremely uniform distribution of Early Jurassic continental biotas.