DNA phylogeny of the extinct marsupial wolf

Abstract

The phylogenetic affiliation of the extinct marsupial wolf (Thylacinus cynocephalus), which once was widespread in Australia, has been uncertain. On the basis of morphology, some systematists argue that the thylacine was most closely related to an extinct group of South American carnivorous marsupials, the borhyaenids, whereas others consider it to be closer to Australian carnivorous marsupials. Here we use direct sequencing by means of the polymerase chain reaction (PCR) to compare 219 bases of mitochondrial (mt) DNA from museum specimens of the marsupial wolf and representatives of six genera of extant marsupials. In agreement with the results of an antigenic study of albumin, our genetic data suggest that the marsupial wolf was more closely related to other Australian marsupial carnivores than to those of South America. Thus, the marsupial wolf represents an example of convergent morphological evolution to South American carnivorous marsupials as well as to true wolves.