Los Llanos Formation

The Los Llanos Formation was first formally described by Bodenbender in 1911. The formation crops out in very localized patches in the south of La Rioja Province. Los Llanos Formation is found on the western and eastern slopes of the eponymous Sierra de Los Llanos, in the Sierra de Chepes, Sierra Ulapes, Sierra de Velasco and Sierra Brava. Between the original definition of "Los Estratos de Los Llanos" (Los Llanos Beds) by Bodenbender and later analysis during the twentieth century, a number of controversies arose. Rusconi (1936), Bordas (1941), Pascual (1954), Guiñazú (1962) and Zuzek (1978) assigned a Miocene age to the formation, based on mammal fossils found in the strata. This unit is presently known as the Las Mulitas Formation. The occurrence of typical Cretaceous charophytes confirms the assigned age for Los Llanos Formation. while in the region of Tama the formation reaches an estimated thickness of . It comprises lightgrey and orange sandstones with basal conglomerate beds, The more than 90 sauropod nests were found in direct association with these hydrothermal vents, suggesting a preferred incubation location of the mother dinosaurs. == Paleontological significance ==

The formation has provided fossilized nesting sites attributed to a titanosaurid dinosaur. Research conducted in 2015 by Hechenleitner et al. include a comparison with the Cretaceous Sanpetru Formation of Hațeg paleo-island in Romania, the Tremp Formation of the Spanish Pre-Pyrenees and the Boseong Formation of the Gyeongsang Basin in South Korea. Fossil content The following fossils were reported from the formation: ==== Dinosaurs ==== Crocodyliformes ==== Oofossils ==== ==== Invertebrates ==== === Flora === == See also ==