Bat update

One really cool thing about this picture (earlier) is that you can see the anatomy quite clearly.

Among us tetrapods, bats, birds and pterodactyls all evolved wings independently.

You can see the bat solution here. There's a shoulder, arm, forearm, wrist. The wing is supported on elongated fingers: it's its hand. The thumb remains free and is useful when crawling on all fours. The first finger is diminished and is barely visible on the leading edge of the wing.

There are some nice drawings of wings here.

More bats.