You never said what a "variation" is, that's your problem.
A "variation" is a "species." That is what
you said, and that is what I'm going by. According to you, all the "species" we see today are simply variations of their respective syngameons.
Let us look at the Ceratopsian "family" or "syngameon," as one example, to see the vast variations in syngameons (species) which we have found in the fossil record. Keep in mind, that fossilization is an extremely rare event, meaning that what we have found so far represents only a small percentage of the fossils in existence today, and of the amount of species which existed in the dinosaur age itself.
Infraorder Ceratopsia
Yinlong - (Xinjiang, western China)
Family Chaoyangsauridae
Xuanhuaceratops - (Hebei, China)
Chaoyangsaurus - (Liaoning, northeastern China)
Family Psittacosauridae
Psittacosaurus - (China & Mongolia)
Hongshanosaurus - (Liaoning, northeastern China)
Liaoceratops - (Liaoning, northeastern China)
Yamaceratops - (Mongolia)
Archaeoceratops - (Gansu, northwestern China)
Auroraceratops - (Gansu, northwestern China)
Family Leptoceratopsidae
Bainoceratops - (Mongolia)
Leptoceratops - (Alberta, Canada & Wyoming, USA)
Montanoceratops - (Montana, USA)
Prenoceratops - (Montana, USA)
Udanoceratops - (Mongolia)
Family Protoceratopsidae
Graciliceratops - (Mongolia)
Bagaceratops - (Mongolia)
Breviceratops - (Mongolia)
Lamaceratops - (Mongolia)
Magnirostris - (Inner Mongolia, China)
Platyceratops - (Mongolia)
Protoceratops - (Mongolia)
Superfamily Ceratopsoidea
Zuniceratops - (New Mexico, USA)