A separation exists between the tooth microwear of extant ruminant browsers and grazers when examined with new statistical techniques such as the dichotomous, polychotomous and continuous methods. Extant mixed feeders, however, could not be discerned as a distinct group. Many variables were used in the analysis, including two new variables; the area and perimeter of scars.A standard definition of a pit is deduced and a recommendation is made for a method and a model which best charactrizes the enamel scars for determination of browsing and grazing dietary categories. The best diagnostic method of tooth microwear analysis utilizes the number of pits smaller than or equal to the ratio four (lenth over width), the number of scratches between four and 100 micrometres in length to width ratio, and the number of gouges greater than 100 micrometres in length to width ratio. Browsers have many pits and few scratches, with the exception of the giraffe. Grazers have many scratches and few pits, with the exception of the common waterbuck.
The tooth microwear analysis suggests that Tragoportax amalthea (Boselaphini, Bovidae) was a mixed feeder at Pikermi and a grazer at Samos. Using the dietary adaptations and the time differences (Pikermi is slightly older than Samos), it is assumed that we ahve recorded evolutionary change from a mixed feeder to a grazer. Tragoportax rugosifrons from Samos was a grazer. Pikermi and Samos are Miocene (Turolian) localities in Greece.