More mammal-like jaw and teeth. Started when therapsids developed a stronger mammal-threshold package: more mammal-like jaws and teeth, plus features like a secondary palate, which helped separate breathing from chewing. I’d use “mammal-like jaw and teeth” as the public-facing marker.
Using Tritylodontidae again, same as last n0n-mammaliaform therapsid. They are the best public-facing “last non-mammal cynodont” marker: advanced, rodent-like, herbivorous cynodonts that persisted into the Early Cretaceous. Nature describes tritylodontids as nonmammaliaform herbivorous cynodonts that originated in the Late Triassic, diversified in the Jurassic, and survived into the Early Cretaceous.
Last Non-Mammaliaform Cynodonts Read More »
For the beginning of Cynodonts, use the Late Permian, around 260 MYA, with early forms such as Procynosuchus. This is the branch where the mammal-like jaw, teeth, palate, and breathing package really starts tightening toward mammals.
