The synapsids were the greatest evolutionary link between reptiles and mammals. They were animals with both reptilian and mammalian features. In fact, they started out as reptilian, but soon evolved to look more mammalian. Having started out in the Carboniferous period, the synapsids had flourished during the Permian period, and even started to show uniqueness in themselves. In the early Permian, there were reptilian pelycosaur synapsids, while in the late Permian, there were mammalian therapsid synapsids. Soon, in the Jurassic period, the synapsids would soon evolve into a new type of animal: the mammals.
Synapsids Throughout Time (note that those are not all the ones that exist)Edit
Triassic Synapsids (excluding mammals)Edit
Jurassic Synapsids (excluding mammals)Edit
Cretaceous Synapsids (excluding mammals)Edit