The species Glirodon grandis, also described by Engelmann and Callison, has been found in the Upper Jurassic formations of Dinosaur National Monument in Utah (USA). Other than being a large, early American Multituberculate, (see Multituberculata), the nature of this beast is somewhat unclear. It's an "allodontid (two families and the genus Glirodon)", (Kielan-Jaworowska and Hurum, 2001). It had gliriform incisors; incisors with the "enamel reduced to a stripe on the front side." Apparently, this condition evolved several times among Multituberculates.
It's based on a portion of snout. "Glirodon retains the plesiomorphic 'plagiaulacidan' ("Plagiaulacida") dental formula and shares with Allodontidae the structure of the upper premolars (Pl.1 fis 2-4). It differs from the Paulchoffatiidae and Plagiaulacidae in having a single-cusped I3," (Kielan-Jaworowska & Hurum, 2001, p.401-402). I3 refers to an upper incisor and 'plesiomorphic' means 'basal'.
Present in stratigraphic zones 4 and 6.