The temnospondyl labyrinthodonts of the earliest Triassic

Abstract

ABSTRACT Most species of the order Temnospondyli from the lowermost Triassic may be classified under ten well defined families, although a few species are of uncertain family allocation. The ten families occur variously in ten tetrapod assemblages scattered over Pangaea. These assemblages are very similar in taxonomic composition indicating: (1) general contemporaneity among them; (2) the presence of open routes for dispersion through and around the land area of the time; and (3) similarity in climatic and ecologic conditions from high southern latitudes to high northern latitudes. The lowermost Triassic is here defined as the Griesbachian, Dienerian, and Smithian Stages, and the tetrapod assemblages ranging through these levels are here, compositely, named the Triassic A1 horizon. Some dispersion routes for temnospondyls seem to have been overland on Pangaea and some along its shoreline. A single terrestrial and fresh-water tetrapod ecosystem was generally ubiquitous over Pangaea, although there is some ...