We describe sauropod material from the Lower Cretaceous (Aptian-Albian) Puesto Quiroga Member of the Lohan Cura Formation, exposed at the Cerro Aguada del León locality (La Picaza area, Neuquén Province, Argentina). The remains consist of disarticulated elements of at least three individuals, and are assigned to an indeterminate species of the rebbachisaurid diplodocoid Limaysaurus gen. nov. Elements from various parts of the skeleton are represented: a tooth, partial dorsal, sacral, and caudal vertebrae, a haemal arch, coracoid, humerus, ilium, pubes, ischium, femora, a tibia fragment, and an incomplete fibula. The Lohan Cura specimens are strongly reminiscent of corresponding elements in the holotype of Limaysaurus tessonei (=“Rebbachisaurus” tessonei, “Rayososaurus” tessonei) from the overlying Upper Cretaceous (lower Cenomanian) Candeleros Formation. We evaluate the phylogenetic relationships of Limaysaurus gen. nov. and other diplodocoids, and provide hypotheses regarding sauropod evolution during the Cretaceous.