The phylogenetic relationships of the Bilby, Macrotis lagotis (Peramelimorphia : Thylacomyidae), to the bandicoots - DNA sequence evidence

Partial sequencing of the 12S ribosomal RNA gene was used to test two compe ting hypotheses concerning the phylogenetic relationship of the bilby (Macr otis lagotis) to the Australian and New Guinean species of bandicoot. The f irst hypothesis proposes that the Australian and New Guinean bandicoots are in a monophyletic clade to the exclusion of the bilbies, whereas the secon d hypothesis proposes that the bilby is monophyletic with the Australian ba ndicoots to the exclusion of the New Guinean bandicoots. Phylogenies determ ined by both maximum-likelihood and neighbour-joining approaches supported the first hypothesis in which the bilby is excluded from the clade represen ted by the Australian and New Guinean bandicoots. Monophyly of the Australi an and New Guinean bandicoots is consistent with the biogeographical scenar io in which Australia and Papua New Guinea have undergone repeated connecti on and disconnection over the last 20 million years. (C) 2001 Academic Pres s.