Funcion del pteroides en el vuelo de los Pterosaurus

High lift function of the pteroid bone and forewing of pterosaurs

Matthew T. Wilkinson1,*, David M. Unwin2 and Charles P. Ellington1 1Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK 2Institut fu¨ r Pala¨ontologie, Museum fu¨ r Naturkunde, Humboldt-Universita¨ t zu Berlin, Invalidenstrasse 43, Berlin 10115, Germany

The pteroid bone is a rod-like element found only in pterosaurs, the flying reptiles of the Mesozoic. It articulated at the wrist, and supported a membranous forewing in front of the inner part of the wing spar.
The function of this bone, particularly its orientation, has been much debated. It is widely believed that it pointed towards the body, and that the forewing was relatively narrow. An alternative hypothesis states that it was directed forwards during flight, resulting in a much broader forewing that acted as a leading edge flap. We tested scale models in a wind tunnel to determine the aerodynamic consequences of these conflicting hypotheses, and found that performance is greatly improved if the pteroid is directed forwards: the lift : drag ratios are superior and the maximum lift is exceptionally high in comparison with conventional aerofoils.