Tapejarid pterosaurs are known from the middle portion of the Cretaceous period in rocks from Asia, Europe, and South America. They are famous for crests of varying size on their cranium, a curved jaw margin, as well as having large "chin-crests" on the bottom of their lower jaws. Tapejarids are closely related to the thalassodromids that often have huge crests restricted to their cranium and straight jaw margins.
Aymberedactylus cearensis is a tapejarid that was named by Rodrigo Vargas Pêgas, Maria Eduarda de Castro Leal, and Alexander Kellner in September, 2016. It was discovered in Lower Cretaceous rocks of the Crato Formation in Ceará, Brazil deposited approximately 110 million years ago. The Crato Formation is made of fine-grained limestones and was deposited in a warm-water coastal lagoon environment. The name Aymberedactylus cearensis is derived from the Tupi word "aymbere" meaning "small lizard and the Greek word "dactylus" meaning finger, and honors the state of Ceará.
Aymberedactylus is known from a single lower jaw that shows some features seen in both thalassodromids and tapejarids. In dorsal view, the lower jaw is remarkably Y-shaped, with nearly 50% of its length made up of a symphasis where the left and right jaws were fused at the midline. Unlike many tapejarids, the oral margin of the lower jaw is fairly straight, but it does record the base of a "chin" crest on the lower jaw like what's seen in tapejarids. Although the remains of Aymberedactylus are incomplete, the authors of the 2016 study calculated that it had a wingspan of about 2 meters (6.5 feet) based on comparison to similar pterosaurs.
To help pin down where exactly in the pterosaur family tree Aymberedactylus lies, Pêgas and colleagues performed a phylogenetic analysis comparing Aymberedactylus to other tapejarids. They found that Aymberedactylus was at the base of the tapejarid clade, diverging from that group earlier than the other tapejarids like Tapejara, Tupandactylus, and Sinopterus. More distantly related are the thalassodromids, and a clade made up of azhadrchids and chaoyangopterids.
The Crato Formation was deposited in a warm-water near-shore lagoon and it is made up of fine-grained limestone. It preserves a large number of organisms in exceptional detail and is considered to be a lagerstätte. Besides Aymberedactylus, the Crato Formation preserves the tapejarid Tupandactylus, and other pterosaurs including Arthurdactylus, Brasileodactylus, Lacusovagus, and Ludodactylus. About 20 million years after the Crato Formation was deposited the Santana Formation was laid down in the same area and was also a lagerstätte preserving a similar population of animals.