Morphological variation among populations of the mountain brushtail possum, trichosurus-caninus ogilby (phalangeridae: Marsupialia)

The results are described of a study of morphometric variation among populations of the mountain brushtail possum, Trichosurus caninus Ogilby. Trapping surveys were completed at seven sites from southern Victoria to central Queensland. The variables measured from each of the 102 animals captured included head length, skull width, total body length, tail length, pes length, length of the ear conch, body girth, belly girth and the pelage colour. Canonical variate analysis highlighted the existence of a marked separation between populations in Victoria and those in New South Wales and Queensland. The first canonical variate accounted for 89% of the variation between the populations and was dominated by the length of the ear conch, tail length and pes length. There also were differences between the populations for several other morphometric measures including the head and body length. We recorded considerable variation in the fur colour of T. caninus both within and between the populations surveyed. However, no consistent pattern in the geographic variation of fur coloration was evident. We do not know the ecological or evolutionary causes underlying the observed differences in morphological characteristics amongst the populations of T. caninus. Further work is planned to examine the genetic variability of the populations and to assess the taxonomic significance of our findings.