The implications of function on the origin and homologies of the dipterous wing

Abstract

Abstract The origin of Diptera, and the homologies of the dipteran wing, are re‐examined in the light of recent studies on the flight biomechanics and functional wing morphology of Diptera and ofPanorpa. Significant Diptera apomorphies are identified, relevant fossils discussed, and a hypothetical wing ground‐plan figured.The arculus, the modified clavus and the anteroposterior asymmetry of the fly wing seem to be adaptations to a mode of flight in which instantaneous wing pitch and camber are controlled automatically, rather than by muscular action; probably in association with the development of asynchronous power musculature.Tillyard's Cu2 (=CUP) is believed to be a secondary pseudo‐vein, his 1A to be the true CuP and 2A to be 1A.The late Permian fossil Permotipula Patricia is almost certainly a member of the Diptera stem‐group, possibly even of the crown‐group. The Mesozoic Laurentipteridae and the Permian Permotanyderidae are other possible, but not certain, stem‐group members.