The skeletal reconstruction of Barosaurus lentus in the American Museum of Natural History

The rearing mounted skeleton of Barosaurus lentus in the Roosevelt Memorial Hall of the American Museum of Natural History (AMNH) is among the most culturally influential of all dinosaur exhibits. We review the history of the genus and of AMNH 6341, the specimen on which the mount is principally based. Excavated by Earl Douglass from the Carnegie Quarry at what is now Dinosaur National Monument, this skeleton was divided between three institutions before Barnum Brown reunited it at the AMNH around 1930. It was then largely neglected for six decades. We document the conception of the rearing mount during the 1986–1991 renovation of the fossil halls, when Lowell Dingus and Eugene Gaffney independently arrived at the idea of a rearing sauropod inspired in part by Gregory S. Paul’s painting Ambush at Como Creek, and the construction of the cast by Research Casting International. At about 15 m, it is the tallest free-standing mounted skeleton in the world. Crucially, the mount’s purpose was not to assert that Barosaurus habitually reared, but to provoke visitors to think about what fossils can and cannot tell us about extinct animals. About 80% of the material in the mount was cast from AMNH 6341. Almost all of the rest was cast from second-generation molds of the Carnegie Diplodocus, including a third of the neck and some residual camarasaurid material in the manus. We summarise the controversy the pose provoked, trace the longer history of rearing sauropods in science and art, and assess the mount’s substantial impact on popular culture.