Dragons
One thing I feel like people don’t consider when thinking about Dragons is that they probably would have hollow, or at least really really light bones. I mean, think about it. They’re huge. There’s no way those thin membranes on their wings are gonna hold them up unless their skeletal structure is light as fuck. That or they basically have no muscles. And also, they probably would have hip sockets similar to birds and some species of Dinosaur, and they would also have a chest bone that humans don’t posses to help them hold more muscle without taking more space. Maybe that's why they tend to have ridges down their chest. Their claws would be really bad weapons because they’re hollow, so that explains the evolutionary need for a breath weapon.
And water dragons might have whale-like tails rather then a more reptilian one, because seriously, just lashing a thin tail back and forth is useless when you’ re swimming. Hell, they might have bigger talons because they need to move more water at once and they’d be clumsy as hell on land, constantly tripping over their own talons.
Acid dragons would have special immune systems maybe, making them immune to most poisons.
Fire and Desert dragons must have the highest heat resistance ever. Just imagine, their jungle dragon buddy crashing from heatstroke while they’re completely fine, if maybe a little sweaty. They probably have really thin scales, very porous to release any excess heat.
These have been my very weird and very short thoughts on dragon anatomy.
