Prozostrodontia

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Prozostrodontia
Temporal range: Late Triassic–Recent
Kayentatherium wellesi.jpg
Skull of Kayentatherium wellesi
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Order: Therapsida
Suborder: Cynodontia
Superfamily: Chiniquodontoidea
Clade: Prozostrodontia
Liu and Olsen, 2010

Prozostrodontia is a clade of cynodonts including mammals and their closest non-mammaliform relatives such as Tritheledontidae and Tritylodontidae. It was erected as a node-based taxon by Liu and Olsen (2010) and defined as the least inclusive clade containing Prozostrodon brasiliensis, Tritylodon langaevus, Pachygenelus monus, and Mus musculus (the house mouse). Prozostrodontia is diagnosed by several characters, including:

Prozostrodontia includes tritylodontids, which have traditionally been placed within the more primitive cynodont group Cynognathia as distant mammal relatives. It also includes Tritheledontidae, which has long been placed close to mammals. Most previous studies considered Tritheledontidae a valid monophyletic grouping, meaning it was a true clade including all the descendants of a single common ancestor, but Liu and Olsen (2010) found Tritheledontidae to be a paraphyletic series of basal prozostrodontians. Below is a cladogram from Liu and Olsen (2010) showing the phylogenetic position of Prozostrodontia:[1]

Cynodontia 

Procynosuchus



Galesaurus




Thrinaxodon



Platycraniellus


Eucynodontia
Cynognathia

Cynognathus


Gomphodontia

Diademodon




Langbergia




Trirachodon




Sinognathus


Traversodontidae

Pascualgnathus



Luangwa



Scalenodon angustifrons



Scalenodon hirschoni




Massetognathus



Exaeretodon









Probainognathia

Ecteninion




Chiniquodon




Probainognathus


Prozostrodontia

Prozostrodon




Therioherpeton




Riograndia




Pachygenelus



Tritylodontidae

Oligokyphus




Kayentatherium




Tritylodon



Beinotherium







Brasilodon


Mammalia

Adelobasileus




Sinoconodon



Morganucodon
















References[edit]

  1. ^ a b Liu, J.; Olsen, P. (2010). "The Phylogenetic Relationships of Eucynodontia (Amniota: Synapsida)". Journal of Mammalian Evolution 17 (3): 151. doi:10.1007/s10914-010-9136-8.  edit