Tonguez said:
My theory is that Dragons are pelycosaurs clade which developed a double sail (form from elongated vertebral spines) which eventually developed into wings.
Anyway as Pelycosaurs dragons are not reptiles but rather synapsids.
Synapsids are a group of animals that include Pelycosaurs, Gorgonopsia and moderd Mammals. All but Mammals are now extinct (although personally I beleive that the Monotremata (Platypus and Echidna) should be classified as Therapsids)
I had a similar idea for my world (Renya), in which there were several evolutionary pathes on my world that weren't on Earth; one was that of lung-breathing arthropods (thus removing the restrictions on size imposed on insects by their tracheal breathing system) eventually giving riose to some of the "insectoid" mosters (and sometimes becoming as intelligent as mammals rather than "vermin"). another was of another developmental path splitting from reptiles, parallel to birds and mammals, developing warm blood and a fully-partitioned heart (as some dinosaurs were speculated to have), and bird-style reproductive habits (both parents nest; parents take care of their young after hatching as opposed to most reptiles), while retaining several reptilian characteristics (laying eggs, scaled skin, claws, and, in most cases, tails) this new group has eventually developed into a wide variety of post-reptillian creatures, including (among others) Dragons, Kobolds, Lizardmen and
Celirans. Celirans and Lizardmen are related to each other (think Human and Gorilla), but quite distantly related to Dragons and Kobolds (think Human and Whale); Dragons and Kobolds are as related to each other as Humans and Gibbons are.
Magic is a natural force in my world; most sentient (and sometimes non-sentient) organisms have evolved a latent ability to manipulate it - and thus could becomes wizards or sorcerers - and some organisms have evolved far more active means to utilize magic for their survival. Dragons are a prime example of the latter - think of them as the "baleen whales" of their clade, but with far deeper ties into magic than most other natural beings.
Now, ofcourse, powerful mages and spirits have the ability to mess with the genetic makeup of animal and plant lifeforms - and hence the oulbears and many other magical beasts and abberations (though many are natural, such as, for example, mindflayers and aboleths, which are related by the way).