The late Jurassic Paulchoffatiinae, one of two named subfamilies of the family Paulchoffatiidae (suborder Plagiaulacoidea), are generally recognized as the most primitive known, undoubted multituberculates (e.g., Hahn, 1969; Clemens and Kielan-Jaworowska, 1979; Hahn and Hahn, 1983; Hahn et al., 1989). Despite the primitive morphology of members of this subfamily (Paulchoffatia and Pseudobolodon), three features have been posited as autapomorphic for the subfamily (or family), and thus to preclude it from the ancestry of later multituberculates: 1) the distribution of cusps on M2 (Hahn, 1969, 1971); 2) the complex structure of I3 (Hahn, 1969, 1971); and 3) the position of M2 relative to M1 (Van Valen, 1976; Clemens and Kielan-Jaworowska, 1979; Hahn, 1987). Van Valen (1976) argued that the first two features are not unequivocally autapomorphic for paulchoffatiines and that they could, and indeed should, be considered primitive for the order. Hahn (1977) responded to Van Valen's assessment but Clemens and Kielan-Jaworowska (1979, p. 138) opined that “neither argument is particularly compelling” in light of the poor early record of multituberculates and the consequent lack of knowledge concerning morphological variability.