In 1980, Paul de Buisonjé named a new pterosaur from the Romualdo Member of the Santana Formation of northeastern Brazil, Santanadactylus brasilensis. It was the third named pterosaur taxon from Brazil’s Araripe Basin which is home to dozens of incredible pterosaur specimens. S. brasilensis is based on a partial right humerus and right shoulder, as well as two neck vertebrae that de Buisonjé thought were from the same individual. In 1983 Peter Wellnhofer and colleagues refered a pterosaurian notarium to S. brasilensis based on its similar size. Its name honors the Santana Formation and Brazil.
In 1985 Peter Wellnhofer named three new species in the genus Santanadactylus from the Santana Formation: S. spixi, S. pricei, and S. araripensis. Santanadactylus spixi is based on bones from the forearm, wrist and hand. The name honors Johann Babtist Spix, a Bavarian naturalist who was part of an expedition into Brazil’s interior in 1817-1820. Santanadactylus pricei is also known from forearm, wrist, and hand bones, as well as a referred humerus. It is named for pioneering Brazilian paleontologist Llewellyn Ivor Price. Santanadactylus araripensis is based on a partial skeleton that includes skull material. Its name honors the Araripe Basin.
The original specimen of S. brasilensis is a humerus and shoulder girdle found in a concretion. The humerus has a large trapezoidal flange called the deltopectoral crest near its proximal end. Its distal border is nearly straight and perpendicular to the long axis of the humerus. The plane of the deltopectoral crest is slightly twisted with respect to the long axis of the humerus. The deltopectoral crest is distinctive and unique among Santana pterosaurs. There is a pneumatic foramen near the proximal end which is similar to what’s seen in ornithocheirids.
Many authors have doubted the association of the neck vertebrae and the limb bones, noting that their proximity is not enough. Additionally, the referral of the notarium was based solely on size, and may have been from any number of other pterosaurs. Nothing else is definitively known from S. brasilensis, but based on comparisons to other ornithocheirids it probably had a wingspan of about 4.0 to 4.5 meters (13-15 feet).
“Santanadactylus” spixi is no longer considered a member of the genus. In 1989 Chris Bennett considered it to be a dsungaripterid because of its similar wrist bones. Later, it was interpreted as a tapejarid by Kellner or a thalassodromid by Unwin and Witton.
In 2000 Alexander Kellner and Yukimitsu Tomida reviewed different Araripe Basin pterosaurs. They considered S. pricei to be not diagnostic, and referred S. araripensis to the genus Anhanguera.
Ornithocheirids are narrow-winged aerial fishers with elongated snouts lined with numerous cone-shaped teeth. Many ornithocheirids, such as Anhanguera and Tropeognathus had semicircular crests on the ends of their upper and lower jaws, and its likely Santanadactylus would have had them as well. When Santanadactylus was alive, about 105 million years ago, it was one of several ornithocheirids that fished in the lagoons and shallow waters of the newly formed Atlantic Ocean.