The Multituberculata are an extinct order of Mammals characterized by unusual molariform teeth with multiple cusps and ridges, unlike modern placental mammals whose molars are variations on a four-cusp pattern. The anterior dentition resembles that of modern rodents, and the multituberculates are assumed to have had a similar niche. Multituberculates were the longest-lived mammalian order, extending 160MYr from the origin of mammals in the  Jurassic until the radiation of rodents during the Eocene.