Multituberculata

INTRODUCTION The Multituberculata are named for their unusual teeth, which have multiple molar cusps, or “tubercles,” arranged in longitudinal rows. Although now extinct, multituberculates were among the most successful of mammals by any criterion. Multituberculata is the longest-lived order within Mammalia, with a range extending from at least the Kimmeridgian (Late Jurassic) to the Chadronian (late Eocene). Multituberculates were widely distributed and are known from throughout Laurasia. Isolated teeth and tooth fragments suggest that they were also present in the Cretaceous of Africa (Sigogneau-Russell, 1991; Hahn and Hahn, 2003) and Madagascar (Krause et al., 2006) and possibly from Argentina (Kielan-Jaworowska et al., 2004). Multituberculates were diverse and common – so much so that they are commonly employed as stratigraphic index fossils in the Late Cretaceous and Paleocene of North America (Krause, 1982a; Savage and Russell, 1983; Lillegraven and McKenna, 1986; Sloan, 1987). The greatest known diversity of multituberculates for any single area and time period is that of the North American middle Paleocene, but in recent years burgeoning numbers of newly described taxa from the Cretaceous of North America (Eaton, 1995; Eaton and Cifelli, 2001), and the Cretaceous of Asia (Kielan-Jaworowska and Nessov, 1992; Rougier, Novacek, and Dashzeveg, 1997) have suggested that our documentation of the group remains woefully incomplete. Where they occur in North America, multituberculates are common.