Individuals occupying deciduous woodland environments show an occlusal wear pattern characterized by large lingual phase I facets and reduced buccal phase I facets.
We note, however, that depending on the orientation of phase I facets, significant grinding also occurs along phase I facets during phase I.
Phase I movement is said to be associated with shearing along a series of crests, producing planar phase I facets and crushing on surfaces on the basins of the molars.
Pairwise NPMANOVAs between all pairs of groups was based on three variables (relative areas of buccal phase I facets, lingual phase I facets and phase II facets).
The Vancouver islanders show the highest variation, especially in lingual phase I facets and phase II facets (standard deviation = 9.5).
The steppe and coniferous forest group is characterized by prominent buccal phase I facets, small lingual phase I facets, and phase II facet areas slightly larger when compared to those of deciduous woodland samples.
Once wear facets were identified, they were grouped by chewing cycle phases [39], [60], defining three groups: lingual phase I facets (1, 2, 3 and 4), buccal phase I facets (5, 6, 7 and 8) and phase II facets (9, 10, 11, 12 and 13).
Alternatively, Inuit, Vancouver islanders, and Fuegians are characterized by small lingual phase I facets which are prominent in the Khoe-San and Australian aborigines.
As observed in numerous extant herbivores prominent buccal phase I facets occur in species consuming large amounts of tough, fibrous and flat food items [60].
Lingual phase I facets show values of 34.5% in the deciduous woodland group, 23.0% in the Mediterranean and 19.9% in the steppe and coniferous forest sample.
