>>35395765Bulbasaur line- Dicynodont.. maybe
Chickorita line- Sauropod
Treeko line- Theropod.. well its bipedal
Turtwig line- Ankylosaur/Meiolania
Snivy line-primitive snakes with limbs
Chesnut line- Glyptodonts
Rowlet line- Grallistrix/Ornimehalonyx
I dont buy the whole prehistoric animal theory myself but here ya go