This fine specimen of Rhamphorhynchus muensteri has been preserved with a good portion of the wing membrane. It is a very informative specimen as the wing can be seen to fluoresce under UV light, revealing additional information.
Helmut Tischlinger investigated the wing structure under UV light and was able to identify actinofibrils and a series of transverse structures which may be elastic fibres. The wing also seemed to indicate that there was a muscle fibre layer at the base of the membrane. Such structures would make the pterosaur wing membrane very durable and flexible.
Tischlinger H. and Frey E., 2002. Ein Rhamphorhynchus (Pterosauria, Reptilia) mit ungewöhnlicher Flughauterhaltung aus dem Solnhofener Plattenkalk. Archaeopteryx, 20, 1-20.
Frey E., Tischlinger H., Buchy M.-C. and Martill D. M., 2003, New specimens of pterosauria (Reptilia) with soft parts with implications for pterosaurian anatomy and locomotion: In: Evolution and Palaeobiology of Pterosaurs, edited by Buffetaut E. and Mazin J.-M., Geological Society Special Publication, n. 217, p. 233-266.