Eucynodontia ("true dog teeth") is a clade of cynodont therapsids including mammals and most non-mammalian cynodonts. The oldest eucynodonts are known from the Early Triassic and possibly Late Permian. Eucynodontia includes two major subgroups, Cynognathia and Probainognathia.

The clade was named in 1982 by Thomas Kemp, who defined it as all cynodonts more derived than Thrinaxodon.

In 2001, Hopson and Kitching redefined the clade Eucynodontia as the least inclusive group containing Mammalia and Exaeretodon.

Phylogeny

Cladogram after Stefanello et al. (2023):

Procynosuchus
Galesaurus Thrinaxodon Platycraniellus Eucynodontia Cynognathia Cynognathus Gomphodontia Diademodon Langbergia Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon Probainognathia Lumkuia Chiniquodon Probainognathidae Probainognathus Bonacynodon Ecteniniidae Trucidocynodon Ectenion (sic) Diegocanis Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Galesaurus
Thrinaxodon Platycraniellus Eucynodontia Cynognathia Cynognathus Gomphodontia Diademodon Langbergia Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon Probainognathia Lumkuia Chiniquodon Probainognathidae Probainognathus Bonacynodon Ecteniniidae Trucidocynodon Ectenion (sic) Diegocanis Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Thrinaxodon
Platycraniellus Eucynodontia Cynognathia Cynognathus Gomphodontia Diademodon Langbergia Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon Probainognathia Lumkuia Chiniquodon Probainognathidae Probainognathus Bonacynodon Ecteniniidae Trucidocynodon Ectenion (sic) Diegocanis Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Platycraniellus
EucynodontiaCynognathia Cynognathus Gomphodontia Diademodon Langbergia Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon Probainognathia Lumkuia Chiniquodon Probainognathidae Probainognathus Bonacynodon Ecteniniidae Trucidocynodon Ectenion (sic) Diegocanis Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
CynognathiaCynognathus Gomphodontia Diademodon Langbergia Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon
Cynognathus
GomphodontiaDiademodon Langbergia Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon
Diademodon
Langbergia Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon
Langbergia
Trirachodon Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon
Trirachodon
Sinognathus Traversodontidae Pascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon
Sinognathus
TraversodontidaePascualgnathus Luangwa Scalenodon Mandagomphodon Massetognathus Exaeretodon
Pascualgnathus
Luangwa
Scalenodon
Mandagomphodon
Massetognathus Exaeretodon
Massetognathus
Exaeretodon
ProbainognathiaLumkuia Chiniquodon Probainognathidae Probainognathus Bonacynodon Ecteniniidae Trucidocynodon Ectenion (sic) Diegocanis Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Lumkuia
Chiniquodon Probainognathidae Probainognathus Bonacynodon Ecteniniidae Trucidocynodon Ectenion (sic) Diegocanis Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Chiniquodon
ProbainognathidaeProbainognathus Bonacynodon
Probainognathus
Bonacynodon
Ecteniniidae Trucidocynodon Ectenion (sic) Diegocanis Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
EcteniniidaeTrucidocynodon Ectenion (sic) Diegocanis
Trucidocynodon
Ectenion (sic) Diegocanis
Ectenion (sic)
Diegocanis
Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Protheriodon
ProzostrodontiaProzostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
ProzostrodontidaeProzostrodon Pseudotherium
Prozostrodon
Pseudotherium
Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Therioherpeton
Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Irajatherium
Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Riograndia
Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Diarthrognathus Pachygenelus
Diarthrognathus
Pachygenelus
Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes
Tritylodontidae
Botucaraitherium Brasilodon Mammaliaformes
Botucaraitherium
Brasilodon Mammaliaformes
Brasilodon
Mammaliaformes