Phylogeny of the marsupials

Abstract

The history of study of the Marsupialia begins early in the sixteenth century with discovery of the opossum by Spanish explorers of South America. As further accounts and specimens of the American and, soon thereafter, Australian marsupials reached Europe, biologists allied these new animals with a variety of eutherian (placental) mammals. Linnaeus classified the opossum with pigs, armadillos, hedgehogs and shrews. Kangaroos and wombats were thought to be related to rodents. During the nineteenth century de Blainville emphasised differences of reproductive systems in development of his classification and distinctly separated Didelphia, the marsupials, from the placentals or Monodelphia. It remained for subsequent biologists to recognise the evolutionary significance of this division.