The relationships of the major group of mammals: New approaches

Systematically, mammals must be the most intensively studied group of organisms. Yet the relationships between the major orders - bats, whales, primates, rodents, insectivores, elephants, and so on - are still controversial. New systematic approaches, including molecular sequencing studies and cladisitic analyses of morphological data, have given rise to a number of new phylogenetic hypotheses, but only a few sister-group relationships seem to have general support. These hypotheses are depicted in the accompanying centre-page diagram.