This is Morroth, the abyssal treasure hoarding drake I made for a campaign I was in a while ago.
I designed her with "Earthstriding" in mind, which is a method of travel similar to swimming or flying, but through solid ground. So I thought of including shapes that suggested feathers and fins, without actually using either and ended up with these flat spine things. Abyssal dragons, if I remember right, were described as having flaps of skin for wings, which kind of reminded me of flippers, so I designed the wings sort of like sea turtle fins initially, but I ended up with a shape that looks more like a penguin flipper.
She has a large mouth and expanding throat pouch that allow her to carry a large amount of treasure back to her underground lair. She's supposed to have treasure embedded in her underbelly (but I forgot to render it.)