Cladotheria

Cladotheria is a clade (sometimes ranked as a legion) of mammals. It contains modern therian mammals (marsupials and placental mammals) and several extinct groups, such as the "dryolestoids", amphitheriids and peramurids. The clade was named in 1975 by Malcolm McKenna. In 2002, it was defined as a node-based taxon containing "the common ancestor of dryolestids and living therians, plus all its descendants". A different, stem-based definition was given in 2013, in which Cladotheria contains all taxa that are closer to Mus musculus (the house mouse) than to the "symmetrodont" Spalacotherium tric

Dryolestida is an extinct order of mammals, known from the Jurassic and Cretaceous. They are considered basal members of the clade Cladotheria, close to the ancestry of therian mammals. It is also believed that they developed a fully mammalian jaw and also had the three middle ear bones. Most members of the group, as with most Mesozoic mammals, are only known from fragmentary tooth and jaw remains.

Amphitherium is an extinct genus of stem cladotherian mammal that lived during the Middle Jurassic of England. It was one of the first Mesozoic mammals ever described. A recent phylogenetic study found it to be the sister taxon of Palaeoxonodon. It is found in the Forest Marble Formation and the Taynton Limestone Formation.

Amphitheriidae is a family of Mesozoic mammals restricted to the Middle Jurassic of Britain, with indeterminate members also possibly known from the equivalently aged Itat Formation in Siberia and the Anoual Formation of Morocco. They were members of Cladotheria, more derived than members of Dryolestida, and possibly forming a close relationship with Peramuridae. Amphitheriidae is the only family of the order Amphitheriida.

Vincelestes ("Vince's thief") is an extinct genus of mammal that lived in what is now South America during the Early Cretaceous. It is closely related to modern therian mammals as part of Cladotheria.

The family Peramuridae is a family of mammals that lived in the Late Jurassic and Early Cretaceous. They are considered to be advanced cladotherians, closely related to therian mammals as part of Zatheria.