Cacibupteryx caribensis was discovered in 160 million year old rocks of the Jagua Formation in western Cuba. It was named and described in 2004 by Zulma Gasparini, Marta Fernández, and Marcelo de la Fuente, and is based on a single partial skeleton. The name Cacibupteryx is derived from “Cacibu” the Taino lord of the sky and “pteryx,” the Ancient Greek word for wing. The species name honors the Caribbean Sea.
The specimen consists of a partial skull missing the mandible, and parts of the left wing. The skull and wing bones are preserved in three dimensions, a rarity in Jurassic pterosaurs. The skull is missing the tip of the snout and its teeth, but is otherwise complete. As preserved, it measures just over 15 cm (6 inches), but would have been about 20-22 cm (8-10 inches) long when complete. It's roughly triangular in profile and when seen from above has a low ridge on the skull roof from the nostrils to the eyes. There are six tooth sockets found on each side of the upper jaws, but the missing portion probably held an additional three or four teeth on each side. The sockets show that the teeth are widely spaced and separated by a concave margin. The teeth were circular in cross section, and the roots show that they were stout and directed slightly forward and outward.
The wing bones are fragmentary, and the largest is a partial radius measuring about 11 cm (4.5 inches). Anatomical details of the wing bones allowed Gasparini and colleagues to differentiate Cacibupteryx from the contemporaneous Nesodactylus. Comparison to similar pterosaurs shows that its wingspan was about 200 cm (6.5 feet), although without a complete specimen, this remains an estimate.
Gasparini and colleagues determined that Cacibupteryx was a member of the Rhamphorhynchidae, a widespread family of marine fishing pterosaurs known exclusively from Jurassic rocks. All rhamphorhynchids have long, forward pointing teeth and fished while flying, using the teeth to grasp slippery prey.
Rhamphorhynchids, like many early pterosaurs, all had long, stiff tails with vertical tail veins which they used to balance and stability while flying. Paleontologist Mark Witton regarded Cacibupteryx as a scaphognathine, a subfamily of rhamphorhynchids with widely spaced teeth and skulls that look superficially like upturned motorboats. Phylogenetic analyses done by others, notably Brian Andres and colleagues, have found that Cacibupteryx was most closely related to Rhamphorhynchus itself and Nesodactylus.
At the time Cacibupteryx lived, it patrolled the southwestern shores of the newly formed Gulf of Mexico, the result of North America and other northern continents breaking away from Pangea. The Gulf was near the equator and had a tropical climate. In addition to pterosaurs, the rocks of the Jagua Formation entomb ichthyosaurs, plesiosaurs, and large numbers of fish. The Caribbean is geologically complex, and large parts of Cuba, the Greater Antilles, and Central America actually began as islands in the Pacific that shifted to their current locations by moving into the gap between North and South America as both continents moved westward.