2021-09-10

The diversity of Cretaceous reptile fossils in Argentina is surprising

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The diversity of Cretaceous reptile fossils in Argentina is surprising

South America has some of the most important fossil gathering places in the world, which can help us understand the history of dinosaurs and other Mesozoic reptiles. However, the Late Cretaceous Cerro Fortaleza site in Santa Cruz, Argentina is surprisingly rare. Although different combinations of reptile fossils have been preserved in other nearby locations, the skeletal remains at Cerro Fortaleza are almost entirely confined to one type of dinosaur: the giant long-legged animal Dreadnoughtus. In this study, the researchers used teeth to expand the known diversity of reptiles at the site.

The diversity of Cretaceous reptile fossils in Argentina is surprising(1)

December 2016, in Cerro Fortaleza’s fossil excavation revealed 13 teeth and 9 tiny skeletons (skin bones resembling armor), representing various ancient reptiles. The identification of these remains confirmed the existence of at least three types of dinosaurs: carnivorous raptors, armored dragons and long-necked titansaurus. However, most of the teeth are identified as belonging to a group of terrestrial cousins ​​of crocodiles, known as Perosarons. Although these rare fossils cannot accurately identify species, they indicate that the diversity of reptiles at this site is much richer than previously known.

These remains include some important insights into the geographic extent of certain animals. The appearance of strong dragons (a type of armored dinosaur) at this location marked a geographical connection between the records of these dinosaurs further north in Patagonia and further south in Antarctica. The Perosasaurus (the cousin of the crocodile) at this location represents the southernmost record of this group of dinosaurs. This study shows that small fossil remains like teeth are just as useful in enriching our understanding of the ancient environment and distribution patterns of rare fossil sites of skeletal remains.

The author added: “Sometimes, skeletons do not appear. Therefore, the diversity of dinosaurs and crocodiles in this area is revealed through tiny fossils such as skeletons of teeth and skin. These findings reveal An animal community that has not been discovered before. In particular, the records of tyrannosaurus dinosaurs and Perosol anuras are one of the most primitive records in South America so far.