NonAustralidelphian

NonAustralidelphian refers to a proposed clade of marsupials that excludes the order Peramelemorphia, commonly known as bandicoots and bilbies. This grouping is based on genetic and morphological studies that suggest Peramelemorphia represents a separate evolutionary lineage within Marsupialia. The remaining marsupials, collectively termed Australidelphia, are thought to share a more recent common ancestor than either group does with other marsupials, such as the American opossums and shrew opossums.

The concept of NonAustralidelphian implies that if Australidelphia is a valid monophyletic group, then the marsupials not included in it, primarily the Didelphimorphia (opossums) and Paucituberculata (shrew opossums), would form a distinct evolutionary branch. This branch would be considered the most basal or earliest diverging lineage within the marsupial infraclass. The term itself highlights the exclusion of the bandicoot-like marsupials from the typically defined Australidelphia, suggesting a need for re-evaluation of higher-level marsupial classification.

Current understanding of marsupial phylogeny is still evolving, and while the proposed NonAustralidelphian concept has gained traction, it is not universally accepted. Further research, particularly utilizing a wider range of genetic data and incorporating more extinct marsupial lineages, will be crucial in solidifying or refuting this classification. The debate underscores the complexities involved in reconstructing the evolutionary history of marsupials and their diversification across different continents.