Upper Cretaceous dinosaur nesting sites of Río Negro (Salitral Ojo de Agua and Salinas de Trapalcó-Salitral de Santa Rosa), northern Patagonia, Argentina

摘要: Abstract Twenty three different sites in two areas of Rio Negro Province (Salitral Ojo de Agua and Salitral Santa Rosa-Salinas Trapalco), preserving eggs eggshells from the Allen Formation (Upper Cretaceous) were studied, five egg levels identified. Three types eggshell recognized. Eggs possessing thick Type 1 are abundant both areas, sometimes associated with having thinner shells. included oofamily Faveoloolithidae parataxonomic classification. Eggshell 2 is subdivided into groups (Types 2A 2B), mostly based on mean thickness other parameters. assigned to Megaloolithidae classification, ascribed titanosaurs. A third type (Type 3) only recorded at one localities Agua, level 2). This intimately theropod bones, its microstructure agrees an assignation Theropoda. It Elongatoolithidae.