Extended Data Fig. 8: Derived condition of Cifelliodon and other haramiyidan in orientation and implant of incisor roots, in contrast to the typical condition of other stem mammaliaforms and most multituberculates (palatal view).

a, C. wahkarmoosuch (UMNH VP16771): procumbent implant of incisor roots. b, V. sertichi with procumbent (hypertrophied) incisor roots (based on figure 2 of Krause et al.¹⁸). c, Haramiyavia: the first three incisors are procumbent with elongate and procumbent roots (ventral view of left incisors and premaxillary: left with premaxillary; right premaxillary rendered invisible: based on supplementary figure 1 of Luo et al.⁴). d, Morganucodon watsoni (based on figure 6 of Kermack et al.³⁹). e, Haldanodon exspectatus: vertical orientation of incisors shown by their vertical alveoli (resegmented from the previously published dataset³⁷). f, K. simpsoni (Paulchoffatiidae, Multituberculata) (adapted with permission from Kielan-Jaworowska et al.⁴⁰). g, Paulchoffatia delgadoi (Paulchoffatiidae, Multituberculata) (adapted with permission from Kielan-Jaworowska et al.⁴⁰). h, K. dryas (Paulchoffatiidae, Multituberculata) (adapted with permission from Kielan-Jaworowska et al.⁴⁰). i, Sloanbaatar mirabilis (Djadochtatheria, Multituberculata) (adapted with permission from Kielan-Jaworowska et al.⁴⁰). j, Kamptobaatar kuczynskii (Djadochtatheria, Multituberculata) (adapted with permission from Kielan-Jaworowska et al.⁴⁰). k, Ptilodus montanus (adapted with permission from Kielan-Jaworowska et al.⁴⁰). l, Taeniolabis taoensis (adapted with permission from Kielan-Jaworowska et al.⁴⁰). The procumbent implant of upper incisors is a derived condition for haramiyidans, either on all of the incisors (Cifelliodon and Vintana) or on anterior incisors (Haramiyavia). By comparison, the plesiomorphic condition of incisor implantation is vertical for most stem mammaliaforms (for example, Morganucodon and Haldanodon). All Mesozoic multituberculates have vertical implant of upper incisors, including basal-most paulchoffatiids that are preserved with upper incisors, plagiaulacids and djadochtatherians. However, the Cenozoic ptilodontid and taeniolabidid multituberculates show procumbent incisors. Because Mesozoic multituberculates have vertical implantation of incisors, the procumbent incisors of ptilodontids and taeniolabidids are interpreted to be secondarily derived and convergent (k, l).