title: A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot.
abstract: Titanosauria is an exceptionally diverse, globally-distributed clade of sauropod dinosaurs that includes the largest known land animals. Knowledge of titanosaurian pedal structure is critical to understanding the stance and locomotion of these enormous herbivores and, by extension, gigantic terrestrial vertebrates as a whole. However, completely preserved pedes are extremely rare among Titanosauria, especially as regards the truly giant members of the group. Here we describe Notocolossus gonzalezparejasi gen. et sp. nov. from the Upper Cretaceous of Mendoza Province, Argentina. With a powerfully-constructed humerus 1.76 m in length, Notocolossus is one of the largest known dinosaurs. Furthermore, the complete pes of the new taxon exhibits a strikingly compact, homogeneous metatarsus--seemingly adapted for bearing extraordinary weight--and truncated unguals, morphologies that are otherwise unknown in Sauropoda. The pes underwent a near-progressive reduction in the number of phalanges along the line to derived titanosaurs, eventually resulting in the reduced hind foot of these sauropods.
authors.affiliation: Laboratorio de Dinosaurios, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Avenida Padre Contreras 1300, Edificio ECT, Parque Gene San Martín, (5500) Mendoza, Argentina.|Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), IANIGLA-CCT-Mendoza, Argentina.
authors.forename: Bernardo J
authors.initials: BJ
authors.lastname: González Riga
authors.affiliation: Section of Vertebrate Paleontology, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, PA, 15213 USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Lamanna
authors.affiliation: Laboratorio de Dinosaurios, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Avenida Padre Contreras 1300, Edificio ECT, Parque Gene San Martín, (5500) Mendoza, Argentina.|Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), IANIGLA-CCT-Mendoza, Argentina.
authors.forename: Leonardo D
authors.initials: LD
authors.lastname: Ortiz David
authors.affiliation: Centro Paleontológico Lago Barreales, Proyecto Dino, Universidad Nacional del Comahue, Ruta Provincial 51, km. 65, Neuquén, Argentina.
authors.forename: Jorge O
authors.initials: JO
authors.lastname: Calvo
authors.affiliation: Laboratorio de Dinosaurios, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Avenida Padre Contreras 1300, Edificio ECT, Parque Gene San Martín, (5500) Mendoza, Argentina.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Coria
mesh_terms: D000818:Animals; D001118:Argentina; D005075:Biological Evolution; D001842:Bone and Bones / Q000502:physiology*; D025061:Dinosaurs / Q000033:anatomy & histology* / Q000502:physiology; D005580:Fossils / Q000033:anatomy & histology*; D008124:Locomotion / Q000502:physiology; D010802:Phylogeny