The Museo Argentino de Ciencias Naturales and its collection of dinosaurs. The dinosaur specimens housed in the paleontological collections of the Museo Argentino de Ciencias Naturales have undoubtedly international significance. In addition some have historical value, like Antarctosaurus wichmannianus Huene, 1929, one of the first sauropods in being collected in South America; others are unique in its type, as Amargasaurus cazaui Salgado & Bonaparte, 1991, a dicraeosaurid sauropod of elongated cervical neural spines, and Carnotaurus sastrei Bonaparte, 1985, an abelisaurid theropod with strong frontal horns. The first dinosaur bones incorporated to the collections of the MACN were gathered by Carlos Ameghino, just before his brother Florentino occupied the charge of Director of the Museum. Dinosaur discoveries intensified notably with the arrival to the Museum of Jose Bonaparte, at the end of the decade of 1970. Besides Amargasaurus and Carnotaurus, Bonaparte collected remains of Jurassic dinosaurs, like the sauropod Patagosaurus fariasi Bonaparte, 1986a and the theropod Piatnitzkysaurus floresi Bonaparte, 1986b, which, at their time, formed part of the first association of Jurassic dinosaurs recorded in South America.