Or, rather, how my dragons got their wings. Which was sparked by a strip, Full Frontal Nerdity, in the Summer 2014 Gygax Magazine by Aaron Williams. In panel 7 on p66 the lady fighter notes, “Sure! you’re a vertibrate (sic)! That’s four limbs, max!”
It makes for a good joke, however it’s not as accurate as one might think.
So we’ll take a look at the rhipistians, a group of lobe finned fishes that lived during the Devonian Period. One early rhipistian had nine lobed fines, one dorsal, and eight (four pairs) ventral. A later model lacked the dorsal lobe fine and had just the eight ventral. Later on members of the group were reduced to three pairs of finds, and then two pairs. That is what the later tetrapods inherited. Even later at least two groups of amphibians and three of reptiles, plus the whales, lost their limbs, but that’s another story.
Now how the rhipistians lost their extra limbs is not known. It might be because the genes for those limbs were lost, or other genes started suppressing the expression of those genes, or invading chemicals acted to suppress the genes (we call this epigenetics). However it happened, the result was this group of lobe finned fish were pared down to just two pairs of limbs, which the tetrapods inherited.
Until the early dragons came along. In my scheme of things dragons are archosaurs; much like thecodonts, crocodiles, pterosaurs/pterodaytyls, or dinosaurs/birds.The first dragons were small, arboreal animals, avoiding the ground thanks to the large archosaurs there, and the early terrestrial mammals, and the canopy thanks to the early arboreal mammals living there. Over all these primitive dragons were outclassed to some degree by the competition, and were in the process of dying out.
But then some genes in the dragon genome started being expressed. Not in all groups of dragon, just a few, but it did mean a six legged vertebrate was now scrabbling about trying to survive. Now living in the trees as they did, it wasn’t long until flaps of skin between forelimbs and hindlimbs, with the midlimbs inbetween, began to develop. This flap those dragons with them used to glide between trees.
Still dragons, four and six limbed, where headed for extinction. Until, that is, the skin between forelimbs and mid limbs disappeared, leaving only the skin between mid and hind limbs. While this was going on the mid limb girdle began to migrate forward, to eventually meet and merge with the forelimb girdle. What we would call the shoulder girdle.
While this was going on the mid limbs were changing form and function, coming to act more like wings than legs, though more like bat or pterosaur/pterodactyl than bird. That said, it meant these early flying dragons could fly, but not as well as other flying vetebrates of the time or later. These “mini” dragons now had a chance to survive, but not all that great, for they were relegated to a small niche in the environment.
But that was not the end of the story, for one day a dragon was hatched who had one of the earliest known magickal talents, he could levitate. How levitation led to the dragons we know today is a story of a later time.
And that is how the dragon got his wings.