Evolution of hind limb proportions in kangaroos (Marsupialia : Macropodoidea)

Kangaroos (Macropodoidea: Marsupialia) are a characteristic group of Australo-New Guinean mammals that diversified during the geographic isolation of the Australian continent in the Cenozoic. They are first recorded in the Late Oligocene, although the clade diverged from other diprotodontians around 38 million years ago (mya; Westerman et al., 2002), with early forms perhaps resembling small arboreal ‘phalangerids’ (Flannery, 1982). The purpose of this study is to examine the relationship between locomotor strategy and proportional changes in the proximal limb bones and metatarsals of a range of modern and extinct macropodoids using morphometric analyses. In addition, trends in hind limb evolution through time are investigated, firstly using only observations on extant taxa and inferring ancestral conditions on dated molecular phylogenies, and secondly by adding information from the fossil record. The results suggest that incorporating fossils can drastically change inferences about past diversity and evolutionary trends