Pterosaur flight: The role of actinofibrils in wing function

Abstract

The wings of pterosaurs consisted of a narrow wing membrane or patagium primarily supported and controlled by the hyperelongate forelimb, but also attaching to the side of the body and the hindlimb. The patagium consisted of a thin sheet of extensible skin with slender structural fibers (=actinofibrils) arranged in a posterodistally radiating pattern. The function of the actinofibrils has been variously interpreted as 1) to prevent unwanted flapping of the patagium, 2) to camber the patagium, transferring aerodynamic loads anteriorly and proximally to the metacarpus and antebrachium, and 3) to spread the patagium chordwise. Only the last interpretation is consistent with the available data. The actinofibrils resisted longitudinal compression so as to spread the patagium chordwise, to redirect spanwise tension in the proximal patagium as chordwise tension in the distal patagium, and to permit compact folding.

Keywords:

• Pterosaur
• Flight
• Wings
• Functional morphology

Notes

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