This skeleton of a Chasmosaurine ceratopsian forms part of the Montana Duelling Dinosaurs and Distinguished Fossils collection at Bonhams auction house in New York. Fossils of a Nanotyrannus lancensis and a Chasmosaurine ceratopsian, found in Montana and locked eternally in a fierce death match, could fetch a potential record $9 million when they are sold in New York on Tuesday.