ON THE PRESENCE OF DINOSAURS IN THE PIRGUA FORMATION OF THE SALTA GROUP AND THEIR CHRONOLOGIC SIGNIFICANCE

• Main Authors: José Bonaparte, Gerardo Bossi
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Argentina; Patagonia; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.177; http://paleoglot.org/files/bonaparte%26bossi_67.pdf

The stratigraphic aspects of new fossil localities (Aguas Calientes, Arroyo del Morterito, Salta province, Argentina) with dinosaur and crocodilian remains are given. Two lithostratigraphic profiles are included to show the exact position of the fossils. A titanosaurid dinosaur was found in the Pirgua Formation of the Salta Group, and two teeth, one of a carnosaurian dinosaur and the other of a crocodile, were found in the Yacoraite Formation of the same Group. The titanosaurid is described and compared with known Patagonian forms, and finally assigned to Antarctosaurus. As all the known South American titanosaurids, this one came from Upper Senonian strata, and according to its morphological affinities it is concluded that the Pirgua specimen belongs to that age. It is also indicated that the association of titanosaurids, carnosaurs, and crocodiles represents a good argument for considering these formations of the Salta Group as Upper Senonian. The age of the “Dinosaur Beds ” of Patagonia, and that of the Salta Group, is compared on the basis of new evidence, and it is established that the determination of the present material supports a former chronological assignment given by Schlagintweit (1941). A brief comparison of certain biostratigraphic and physical aspects of the two Upper Cretaceous basins (Salteña and Neuquina), which are probably homotaxic, is made, and some parallel significant details are emphasized. It is mentioned that the Senonian movements of Patagonia and Perú are also marked by the angular unconformity with which the Pirgua Formation sediments begin.