Abstract
Amongst the Macropodidae (kangaroos and wallabies) the morphologically distinct forest wallabies are the most poorly studied. Modern forest wallabies are confined to the rainforests of New Guinea, with three species inhabiting the lowlands (Dorcopsis), two species in the highlands (Dorcopsulus), and one satellite island endemic (Dorcopsis atrata). Due to limited sampling in previous studies, our understanding of the evolutionary history and systematics of these genera is unresolved. We obtained tissue samples from 17 individual Dorcopsis and 26 Dorcopsulus including representatives from five of the six currently recognised species. DNA sequence data was generated from up to three mitochondrial (3116 bp) and five nuclear (4097 bp) loci. Phylogenetic analysis resolved six major lineages and showed that Dorcopsulus was embedded within Dorcopsis, making the latter paraphyletic. Within Dorcopsis, two lineages corresponded to D. hageni and D. muelleri, which were sister taxa. Another two divergent lineages were identified within sampled D. luctuosa, both of which appear to represent distinct species. Within Dorcopsulus, two major lineages were present, distributed north and south of the Central Ranges, at odds with current taxonomy. Major diversification within Dorcopsis/Dorcopsulus occurred during the late Miocene and the mid-Pliocene, the latter likely associated in New Guinea with lowland barriers and orogenic processes including the uplift of the Central Ranges. The paraphyly of Dorcopsis and detection of divergent lineages within some sampled species indicate that some adjustments to current taxonomy are warranted. We recommend the recognition of a single genus of forest wallabies (Dorcopsis) and provisionally recognise seven species.