Late Triassic-Early Jurassic western Gondwana tetrapod correlations

MARSICANO, CLAUDIA

Gramado, Brasil

Workshop; I Workshop - Problems in Western Gondwana Geology; 2007

Late Triassic-Early Jurassic western Gondwana intercontinental correlations based on tetrapods are analyzed. Particularly, former evidence that supported the placement of the TJ boundary in the Karoo Basin is demostrated to be weakly constrained when the putative Lower Jurassic tetrapod faunas of the Upper Elliot are compared with those from the Upper Triassic Los Colorados and Laguna Colorada formations of Argentina. These comparisons are based on recent phylogenetic analysis on basal dinosaurs that support closer relationships between the South African and South American taxa than to other early Mesozoic dinosaurs from Pangea. The position of the TJ boundary in the Karoo Basin, one of the major continental sequences of Western Gondwana, is of particular interest as it would have important implications on our understanding of the patterns of diversification of the Early Mesozoic tetrapod faunas in this part of Gondwana and, consequently, on the alleged worldwide tetrapod continental extinction at the TJ boundary.