I draw lots of dragons (or Dragyns, as I call them). Wyverns, firedrakes, findrakons, hornwyrms- you name it. I have drawings of anatomy (after all, how DO they breathe fire?), skeletons, skin, wings (must have much aerodynamics to lift such a large creature), etc. My veiw is thus: dragons have a seperate "fire chamber," much like a chicken's crop. I mostly draw Wyverns, two-legged, winged dragyns, but the occasional wyrm (legless) pops up too. They (back to wyverns, no) only have two legs (it is physically imposible for a reptile to have four legs and wings. That would be six limbs.) and a pair of wings similar to a pterydactals' or bats'. These amazing creatures, directly decended from pterydactals and pteranodons, are now in hiding, along with the rest of the fe (faeri) race in a land called Terria (Earth in New Elvish), encased within a Magykal Sphere, which no Human may penetrate. Dragyns were originally wild, the elven Dragyn Tribe tamed a rare few. Dragyns are extremely smart: the tame ones think exactly like the incredibly intellegent elves and are able to speak within their Bonds' heads.
While I am at the subject of dragyns I must also mention elves. Elves are much like humans, only they are slightly smaller and much slighter of stature, and posess pointed ears and limited Magyk. There are four Elf tribes: Tiger, Wolf, Horse, and Dragyn, in accordance to their steeds. The males constantly war with the males of other Tribes and are rarely at home. Before a tame dragyn hatches, elves Feel the eggs. If they receive a Feeling called the mesmerai (bonding), they have a Bond with the elf and the elf becomes their Ryder. Dragyns are more than a steed to elves of the Dragyn Tribe, they are friends and companions. There are two variations of the Elvish language: Old Elvish, a system of runes, almost died out; and New Elvish, which is composed of letters.
You can tell I take this very seriously. I should be the administrator of Backyard Dragons.
I will try to post some of my dragyn drawings and anatomy for you later.
(ETA: this is all my personal imagination. Please: it's not copyrighted by law, but it is by mind! Mirre Gorda! (Million Thanks!))