Re-evaluating the generic affinity of 'Silvaroo' buloloensis (Marsupialia, Macropodidae) from the late Pliocene of Papua New Guinea

Australia and New Guinea have experienced episodic connection and separation by high sea levels since the early Miocene. This has markedly influenced biotic patterns, although exactly how remains puzzling in some instances. One example concerns the palaeozoogeography of forest wallabies (Dorcopsini), all six living species of which are found only in New Guinea, even though most dorcopsin fossils recognized are from Australia. Here we review the taxonomic identity of 'Silvaroo' buloloensis from the late Pliocene Otibanda Formation of eastern Papua New Guinea, and show that, according to dental evidence, it is a dorcopsin along with its contemporary, Watutia novaeguineae. Phylogenetic analysis reconstructs 'S.' buloloensis as sister to Dorcopsoides fossilis from the late Miocene of central Australia. The degree of dental similarity between them leads us to include it in the same genus. These findings build upon other recent research on extinct New Guinea macropodines, revealing that both forest wallabies and tree-kangaroos are better represented in the fossil record than previously believed, although intriguingly none are ascribable to modern genera.