PROTEROCHAMPSIDS, MEMBERS OF TRIASSIC ECOSISTEMS FROM SOUTH AMERICA

TROTTEYN, MARÍA JIMENA

San Juan

Congreso; 2° Reunion Conjunta de las Sociedades de Biología de la República Argentina; 2011

Proterochampsids are quadrupedal fossil reptiles with a crocodile-like body and notably skull ornamentation. This group is included within archosauriforms and is considered the sister-taxa of Archosauria. Proterochampsids are endemic for the Middle to the Late Triassic of Argentina and Brazil. The best known proterochampsids come from the Chañares (ca. 241 Ma) and Ischigualasto (ca. 231 Ma) formations (Argentina). In this work two species of Proterochampsids are presented, Proterochampsa barrionuevoi and Chanaresuchus sp nov. The sediments which contained the specimens here analyzed represent a fluvial sedimentary succession. This evidence indicates that proterochampsids were aquatic or semiaquatic animals. Body mass analyses are being carried out taking the circumference of the humerus and femur and applying Anderson´s equation as a mass estimator. The results depicted that proterochampsids had a mass between 1.2 and 28.4 kg. Accordingly, these proterochampsids were medium-sized aquatic animals that inhabited South American Triassic fluvial environments.