Super-family PHALANGEROIDEA

Family Macropodidae

Positional variations in the Macropodidae are summarized in Table 15.1.

Sub-family Macropodinae. Kangaroos and wallabies. 856 specimens examined

The single lower incisor is procumbent; the upper incisors are arranged in an arch. The incisors are separated from the cheek teeth by a long diastema which, in the upper jaw, may contain a small canine. The cheek-tooth rows are curved with the convexity buccally. Figure 15.1 shows a notable feature of the macropods which is that P3 replaces not only m3 but also the tooth that is immediately mesial to it, m2, P2 or PC2, depending on the terminology employed (Chapter 1, p. 13).

In the sub-family Macropodinae, there is mesial drift of the cheek teeth throughout life; this is especially marked in kangaroos (Macropus). In young animals, M1 is opposite the root of the malar process with the developing teeth projecting well back into the infra-temporal fossa; in old animals, M4 may just be posterior to the malar process with a considerable interval between the tooth and the end of the maxilla. As a result of this mesial movement, the most anterior cheek teeth are progressively shed and, in old animals, the molars may be reduced to one in each quadrant. In macropods, Ml is always disproportionately worn, namely more than its eruption as the first in the permanent series of cheek teeth seems to warrant.