Cretaceous 461 Argentina 338 Neuquen Basin 157 South America 154 Patagonia 130 Andes 93 biostratigraphy 88 taxonomy 88 paleoenvironment 62 Ammonoidea 57 ammonite 57 fossil record 57 Lower Cretaceous 52 Neuquén Basin 50 paleomagnetism 50 geochronology 48 Antarctica 45 morphology 45 new species 43 Bivalvia 42 Jurassic-Cretaceous boundary 40 fold and thrust belt 40 paleoecology 40 Early Cretaceous 39 foreland basin 39 Jurassic 37 uranium-lead dating 36 Biostratigraphy 34 tectonic evolution 33 Neuquén basin 32