Archive | Metatheria

The subclass Theria constitutes the "modern" mammals. This group includes three infraclasses, viz., the probably ancestral Jurassic Pantotheria (= Trituberculata), marsupial Metatheria and placental Eutheria, the most highly organised and advanced mammals. Metatheria and Eutheria are presumed to have arisen from some untraced branch of Jurassic pantotheres and both diverged along their separate lines of evolution during early Cretaceous period. [...]