Gnathabelodon is an extinct proboscidean (elephant) genus endemic to North America that includes species that lived during the Middle to Late Miocene. They were called "Spoon-billed Mastodons" since their lower jaw was elongated and shaped like a shoe-horn or spoon. The genus Gnathabelodon consists of two species: Thorpe's Spoon-billed Mastodon (G. thorpei) and Buckner's Spoon-billed Mastodon (G. buckneri).