A giant pterosaur humerus from Mendoza Province, Argentina was described by Leonardo Ortiz David and colleagues in late 2017. It was found at the Agua del Padrillo site in the Upper Cretaceous Plottier Formation in the Neuquén Basin. The pterosaur is too incomplete to justify a scientific name, and the authors referred to it simply as the Padrillo Pterosaur.
The humerus was from the left wing and was found with numerous bones of a different smaller pterosaur, but no other bones of the giant animal were found. It measures 45cm (18 inches) long, and is overall straight and superficially plank-like (although this has been exaggerated by crushing). It has a large flange called the deltopectoral crest that is very close to the shoulder joint. The crest has a rectangular shape, and curls forward, then outward, so that its surface was parallel to the main body of the bone.
Ortiz David and colleagues compared the humerus to a number of other humeri from large, Cretaceous pterosaur taxa. They found that it was most similar to tapejarids and azhdarchids, and determined that it probably belonged to an azhdarchid. Azhdarchids were large pterosaurs with long toothless jaws, long necks, and long limbs. They include the largest of all known pterosaurs, like Quetzalcoatlus and Hatzegopteryx. Comparison of the Padrillo Pterosaur to those giants show that it was slightly smaller, but still huge with a 9 meter (30 foot) wingspan.
Azhdarchids were hunters of small land vertebrates, including dinosaurs, and may have had a mode of life similar to living shoebills. The Padrillo Pterosaur lived about 87 million years ago in a nearly flat, forested plain with meandering rivers. It may have hunted young dinosaurs, as well as lizards, mammals, and amphibians.