Prehistoric Equestria:Unicorn Gemstone

Before the Dragonhorse could split into the three pony species (4 counting the allicorns in) it didn't even had any of the abilities of the modern ponies:it couldent walk on clouds,it couldent conger any magic,it couldent even have cutie marks.Until it somehow found and consumed a magical gemstone,which scientists now call a unicorn gemstone.Once consumed it the Dragonhorse splited into the 3 pony species,each with they're one magical abilities,while other Dragonhorses evolved itno allicorns and posesd all of the other pony abilities.