Uropatagium

Pterosaurs

1. Propatagium: the anterior-most membrane, extending from the shoulder to the wrist. Pterosaurs developed a unique bone to support this membrane, the pteroid.
2. Brachiopatagium: the main flight surface, stretching from the elongated fourth finger to the hindlimbs.
3. Uropatagium or cruropatagium: the posterior-most membrane occurring between the two hindlimbs.
4. A laser-stimulated fluorescence scan on Pterodactylus also identified a membranous "fairing" (area conjunctioning the wing with the body at the neck), as opposed to the feathered or fur-composed "fairing" seen in birds and bats respectively.