Pelycosaur cladogram
PELYCOSAURIA Ophiacodontidae
Ophiacodon
PELYCOSAURIA - Varanopseidae
Varanops
PELYCOSAURIA - Varanopseidae
Pelycosauria - Edaphodauridae
Pelycosauria - Sphenacodontidae
Dimetrodon
Pelycosaur “sails” -- allometry and thermoregulation
Pelycosauria - Sphenacodontidae
Haptodus -- probable therapsid ancestor
Therapsids
“advanced” mammal-like reptiles
CLASS THERAPSIDA
Tetraceratops early Permian, N. Amer.
Phthinosuchus late Permian, Asia
Dincephalia
late Permian, Asia, S Africa
Anomodontia
Dicynodonts
late Permian - mid Triassic
world-wide
to early Cretaceous? -- Australia
Theriodontia
Gorgonopsians
late Permian, S. Africa, Asia
Tritylodonts
late Triassic – mid Jurassic
Eurasia, S Africa, N & S America
Therocephalians
late Permian – early Triassic
Asia, Africa, Antarctica
Cynodonts
late Permian – early Jurassic
Africa, Antarctica, Asia, Europe,
N & S America
Therapsid cladogram
Therapsid evolution
CYNOGNATHUS
SPHENACODONT
PELYCOSAUR
ANCESTOR
THERAPSIDA
Tetraceratops -- earliest Therapsid
THERAPSIDA
Phthinosuchus
THERAPSIDA
Dinocephalia
Titanophoneus
THERAPSIDA
Dinocephalia
Estemmenosuchus
THERAPSIDA
Dicynodontia
Emydops
Diictodon
Kannemeyeria
THERAPSIDA
Dicynodontia
Early Cretaceous -- Australia
?
THERAPSIDA
Tritylodontia
Tritylodon
Kayentatherium
THERAPSIDA
Gorgonopsia
Lycaenops
THERAPSIDA
Therocephalia
Pristerognathus
THERAPSIDA
Cynodontia
Thrinaxodon
THERAPSIDA
Cynodontia
Cynognathus
THERAPSIDA
Cynodontia
Trithelodonts (Ictidosaurs)
late Triassic –
early Jurassic
Therapsida – advanced cynodonts
Trirachodon
Cynognathus
Primitive to advanced cynodonts
Kayentatherium
early Triassic
Probainognathus
late Triassic
Thrinaxodon
early Triassic
Procynosuchus
late Permian
Therapsid evolution toward
Mammalian grade