Amargasaurus (pronounce /əˌmɑrgəˈsɔrəs/; "La Amarga lizard") is a genus of dicraeosaurid sauropod dinosaur from the Early Cretaceous Period of what is now South America. It was small for a sauropod, reaching 10 meters (33 feet) length. It would have been a quadrupedal herbivore with a long, low skull on the end of a long neck, much like its relative Dicraeosaurus. However, this dinosaur sported two parallel rows of tall spines down its neck and back, taller than in any other known sauropod. These spines have been reconstructed supporting skin sails, but the "skin sail" hypothesis was rejected by Gregory S. Paul in 2000.