The Molecular Relationships of Possum and Glider Families as Revealed by Dna-Dna Hybridizations

Abstract

The extant species of possums and gliders (Marsupialia : Diprotodontia) can be classified into one or other of six families-Acrobatidae, Phalangeridae, Burramyidae, Petauridae, Pseudocheiridae or Tarsipedidae. On the basis of morphological and albumin serology studies, these families have been assigned to two superfamilies: the Phalangeroidea (Phalangeridae) and the Petauroidea (all five other families). It has been suggested, however, that the Burramyidae should be placed in the superfamily Phalangeroidea and not in the Petauroidea. We report here on DNA-DNA hybridisation comparisons using representatives from all six extant families of possums and gliders. Phylogenetic analysis of these data was unable to resolve the precise relationships of the Burramyidae viz a viz other families, but the family appeared to be no more closely related to the Phalangeridae than to the four other families. The Burramyidae would probably be best assigned, at present, to a third superfamily. The radiation of the possum and glider families appears to be linked to the change in vegetation associated with the separation of Australia from Antarctica in the early-to-mid Eocene.