Theriimorpha is a clade of mammals defined as including all mammals more closely related to therians (including placental mammals and

marsupial Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...

s) than to

monotreme Monotremes () are mammals of the order Monotremata. They are the only group of living mammals that lay eggs, rather than bearing live young. The extant monotreme species are the platypus and the four species of echidnas. Monotremes are typified ...

Eutriconodonta Eutriconodonta is an order (biology), order of early mammals. Eutriconodonts existed in Asia (including Insular India, pre-contact India), Africa, Europe, North America, North and South America during the Jurassic and the Cretaceous periods. The ...

is usually considered among the most basal members of this group, with other members more closely related to therians like Allotherians placed in the subclade

Theriiformes Theriiformes is a clade of mammals. The term was coined by Timothy B. Rowe in his doctoral dissertation, and is defined as the clade formed by the most recent common ancestor of multituberculates (which form part of the broader group Allotheria ...

, though Eutriconodonta has also been recovered as less closely related to therians than monotremes are in some analyses, placing them outside the

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor ...

Mammalia A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bon ...

. The unusual Late Jurassic digging mammal '' Fruitafossor'' has also been suggested to be a basal theriimorph in some studies. The position of

Allotheria Allotheria (meaning "other beasts", from the Ancient Greek language, Greek , '–other and , '–wild animal) is an extinct clade of mammals known from the Mesozoic and early Cenozoic. Shared characteristics of the group are the presence of lower ...

(which contains the multituberculates, among others) within Theriimorpha is controversial. While many studies recover Allotheria within crown Mammalia as more closely related to therians than to monotremes as a member of the clade

, some studies recover the group as outside of crown Mammalia.

References

{{Taxonbar, from=Q26708524 Mammal taxonomy