Mammaliamorpha is a clade of cynodonts. 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 analyses, but has been recovered outside the clade by others.[1] According to a 2022 study based on inner ear anatomy, Mammaliamorpha may be the clade in which endothermy ("warm-bloodedness") first appeared in the mammalian lineage.[2]

Mammaliamorphs
Temporal range: Late Triassic (Carnian),
232–0 Ma
Skull of Kayentatherium wellesi, a tritylodontid
Manatee
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Clade: Cynodontia
Clade: Prozostrodontia
Clade: Mammaliamorpha
Rowe, 1988
Subgroups

Classification

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Mammaliamorpha was named in 1988 by the American palaeontologist Timothy B. Rowe, who defined it as comprising "the last common ancestor of Tritylodontidae and Mammalia, and all its descendants".[3]

The cladogram below is adapted from the 2019 description of the mammaliamorph Pseudotherium by Rachel V. S. Wallace and colleagues:[1]

Probainognathia

References

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  1. ^ a b Wallace, R. V. S.; Martínez, R.; Rowe, T. (2019). "First record of a basal mammaliamorph from the early Late Triassic Ischigualasto Formation of Argentina". PLOS ONE. 14 (8): e0218791. Bibcode:2019PLoSO..1418791W. doi:10.1371/journal.pone.0218791. PMC 6685608. PMID 31390368.
  2. ^ Araújo; et al. (28 Jul 2022). "Inner ear biomechanics reveals a Late Triassic origin for mammalian endothermy" (PDF). Nature. 607 (7920): 726–731. Bibcode:2022Natur.607..726A. doi:10.1038/s41586-022-04963-z. PMID 35859179.
  3. ^ Rowe, Timothy (1988). "Definition, diagnosis, and origin of Mammalia". Journal of Vertebrate Paleontology. 8 (3): 241–264. Bibcode:1988JVPal...8..241R. doi:10.1080/02724634.1988.10011708.