abstract:Loncosaurus (meaning uncertain; either Araucanian "chief" or Greek "lance" "lizard"Dinosaur Translation Guide L) was a genus of ornithopod dinosaur from the Upper Cretaceous of Provincia de Santa Cruz, Argentina. The type (and only known) species is Loncosaurus argentinus, described by the famous Argentinian paleontologist Florentino Ameghino, but is considered a dubious name.