For those of you who are curious, the Derplings have managed to glean information about Terrarian history from mineral structure of the Terrarian Archipelago that predates even the War of Light and Dark.
The Terrarian Archipelago began as a massive continent, entirely covered by a great forest we have designated "The Primordial Jungle." The only intelligent life on it was the Dragons, which we have learned were sorted into "Shelled," "Scaled," "Feathered," "Gilled," and "Furred" tribes (evidence shows there were others, we simply haven't found enough evidence to know what they were or what became of them.)
The Shelled Tribe were distinguished by their carapace, and sacrificed their gift of flight for interdimensional travel and far greater intelligence. They became the Derplings.
The Scaled Tribe were the most commonly known variant of dragons. They sacrificed their immense physical power for isolation and something close to the human mind. Eventually, their wings atrophied and disappeared because they were never used in the narrow passages and rooms of their temples. They became the Lihzahrds.
The Feathered Tribe fled into the stratosphere during the War of Light and Dark and never returned. They have changed the least compared to the other tribes. They became known as the Wyverns.
The Gilled Tribe had a great schism between those who favored ice and those who favored water. Isolated from each other, they eventually split into two species and lost their minds, becoming the Pigrons and the Fishrons.
Edit: Unfortunately, it looks like we know what happened to the Furred Tribe now...
The Necroavirus targeted them as well as the humans, but they were even more susceptible to it. They fled down to the underworld, but not even the extreme heat could save them. They became the Bone Serpents.