Typical buccal and lingual views of the left upper and lower molars and alveolar capsule conditions of four individuals of Anderson’s red-backed vole a K6059 b K7088 c K7344 d K7367. Arrowheads indicate a root-like strong crevice caused by a crack. Basal ends indicated by white arrowheads and asterisks are considered to be complete closures of re-entrant angles as a root at the basal end and an incipient closure of re-entrant angles, leading to incipient root formation, respectively. Black arrowheads indicate abnormal cracks. Dotted lines indicate outlines of alveolar capsules. Scale bars: 1 mm.