Probainognathia

Probainognathia is one of the two major subgroups of the clade Eucynodontia, the other being Cynognathia. The earliest forms were carnivorous and insectivorous, though some groups eventually also evolved herbivorous diets. The earliest and most basal probainognathian is the Middle Triassic (Anisian) aged Lumkuia, from South Africa, though probainognathians would not become prominent until the mid Norian stage of the Late Triassic.^[2] Three groups survived the extinction at the end of Triassic: Tritheledontidae and Tritylodontidae, which both survived until the Jurassic—the latter even into the Cretaceous (Montirictus and Xenocretosuchus)—and Mammaliaformes, which includes the mammals.^[3]

Probainognathia Temporal range: Middle Triassic–Holocene PreꞒ Ꞓ O S D C P T J K Pg N
Fossil of the probainognathian Chiniquodon theotonicus in the Staatliches Museum für Naturkunde Stuttgart
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Clade:	Cynodontia
Clade:	Eucynodontia
Clade:	Probainognathia Hopson, 1990
Subgroups
†Agudotherium †Candelariodon[1] †Charruodon †Lumkuia? †Protheriodon †Ecteniniidae †Chiniquodontidae †Probainognathidae Prozostrodontia

Phylogeny

Below is a cladogram from Ruta, Botha-Brink, Mitchell and Benton (2013) showing one hypothesis of cynodont relationships:^[4]

Eucynodontia	†Cynognathia Probainognathia †Lumkuia †Ecteninion †Aleodon †Chiniquodon †Probainognathus †Trucidocynodon †Therioherpeton †Tritheledontidae †Riograndia †Chaliminia †Elliotherium †Diarthrognathus †Pachygenelus †Brasilodontidae †Brasilitherium †Brasilodon †Tritylodontidae †Oligokyphus †Kayentatherium †Tritylodon †Bienotherium Mammaliaformes †Sinoconodon †Morganucodon Mammalia

Cladogram from Stefanello et al. (2023):^[5]

Probainognathia	Lumkuia Chiniquodon Probainognathidae Bonacynodon Probainognathus Ecteniniidae Protheriodon Prozostrodontia Prozostrodontidae Prozostrodon Pseudotherium Therioherpeton Irajatherium Riograndia Diarthrognathus Pachygenelus Tritylodontidae Botucaraitherium Brasilodon Mammaliaformes

See also

• Evolution of mammals
• List of prehistoric mammals