Morphological variation among populations of the quokka, Setonix brachyurus (Macropodidae : Marsupialia), in Western Australia

Variation in five external morphological characters was examined among two island populations and five remnant mainland populations of the quokka, Set onix brachyurus. Sexual dimorphism was observed, with males being significa ntly larger than females at each location. Pairwise comparisons among popul ations showed that significant differences were mostly between the two isla nd populations. There was a general trend for animal size to decrease with latitude. Multivariate analyses did not show clear geographic groups, altho ugh the island populations tended to cluster. The inheritance of the morpho logical characters was examined by comparing island populations with those of a captive colony on the mainland, but which originated from the same isl and. Significant differences between these populations were observed for ta il-width measures, suggesting that environmental conditions may be responsi ble for some variation, but considerable variation may also be due to under lying genetic variation.