Typical views of occlusal surfaces (above left) and basal ends (above right), and antero-lingual views (below each) of M2 of three typical individuals a K6059 with alveolar capsules b K7367 without them of Anderson’s red-backed voles and the grey red-backed vole c HEG1-97 with the middle height of the alveolar capsule showing an incipient root. Black and white arrowheads indicate that the basal end was completely closed and that the basal ends were dully tapered off, showing incipient closures of re-entrant angles, respectively. Stars indicate correspondences of anterior points.