Figure 4. Discrimination of the masticatory grades in Muroidea (27 taxa).

PCA performed on morpho-functional parameters CD, K, O and H. PC1 (63% of variance) is strongly supported by the direction of chewing (CD) and by the average orientation of main cusps lowest slopes (O). PC2 (33% of variance) is strongly supported by crown flattening (K). The green area indicates grade B, red area grade M and blue area grade D. Grades C and O are situated in intermediary positions. Cricetine dental plans are shown by circles, intermediary plans are indicated by pentagons and murine plans are represented by squares. Full points indicate cusp interlocking (discontinuous wear facets), while empty points indicate no cusp interlocking (continuous wear facets).