the patagonian opossum has generally 50 teeth. 18 incisors, 4 canines (tooth), 12 premolars, and 16 molars (tooth). their canine is exceptionally long, and they are almost completely straight and vertical. the first pair of incisors are set aside from the other incisors, yet all of the incisors remain the same size. incisor number 1,3,4 on the bottom jaw are curved at the base, while incisor number 2 is straight. the premolars increase in size from the first premolar to the third premolar. the first premolar is very reduced in size compare to the other premolar. the premolars also have a distinct set of cusp on them called the posterobasal cusp. their molars are extremely long, combine all the length of the premolar and it will barely exceed the length of the first two molars. the upper molars are narrow in size, compared to any of the other living opossums.