Campananeyen is a rebbachisaurid sauropod that lived approximately 100 million years ago in the Late Cretaceous of what is now Argentina. Rebbachisaurids are the main group of diplodocoidea to have lived past the Jurassic, and had a more horizontal posture than contemporary sauropods, mainly the titanosaurs. They are unique among sauropods for having batteries of teeth used for chewing, rather than the typical peglike teeth sauropods used to strip leaves off branches.