Xenicibis (image) Yale University Share Print E-Mail Caption The prehistoric Xenicibis used its wings like two clubs hinged at the wrist joint in order to swing at and attack one another. Credit Nicholas Longrich/Yale University Usage Restrictions With credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.