Mammaliamorpha is a clade of

cynodont Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extin ...

s. It contains the clades Tritylodontidae and Mammaliaformes, as well as a few genera that do not belong to either of these groups. The family Tritheledontidae has also been placed in Mammaliamorpha by some

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analyses, but has been recovered outside the clade by others. According to a 2022 study based on

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

anatomy, Mammaliamorpha may be the clade in which endothermy ("warm-bloodedness") first appeared in the mammalian lineage.

Classification

Mammaliamorpha was named in 1988 by the American palaeontologist Timothy B. Rowe, who defined it as comprising "the last common ancestor of Tritylodontidae and

Mammal A mammal () is a vertebrate animal of the Class (biology), 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 ...

ia, and all its descendants". The

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below is adapted from the 2019 description of the mammaliamorph ''

Pseudotherium ''Pseudotherium'' ("false beast") is an extinct genus of prozostrodontian cynodonts from the Late Triassic of Argentina. It contains one species, ''P. argentinus'', which was first described in 2019 from remains found in the La Peña Member of th ...

'' by Rachel V. S. Wallace and colleagues:

References

Prozostrodontia Tetrapod unranked clades Carnian first appearances Extant Late Triassic first appearances Taxa named by Timothy B. Rowe {{Cynodont-stub