Pterodactylus (Greek for "wing finger"); pronounced TEH-roe-DACK-till-us; sometimes called pterodactyl
Shores of Europe and South Africa
Late Jurassic (150-144 million years ago)
Size and Weight:
Wingspan of three feet and two to 10 pounds
Insects, meat and fish
Long beak and neck; short tail; wings of skin attached to three-fingered hands
Pterodactylus is a case study in how confusing it can be to classify 150-million-year-old animals. The first specimen of this pterosaur was discovered way back in 1784, in Germany's Solnhofen fossil beds, decades before before naturalists had any conception of the theory of evolution (which wouldn't be scientifically formulated, by Charles Darwin, until about 70 years later) or, indeed, any grasp of the possibility that animals could go extinct. Fortunately, in retrospect, Pterodactylus was named by one of the first academics to grapple with these issues, the Frenchman Georges Cuvier. (See a gallery of Pterodactylus and Pteranodon pictures and 10 facts about pterodactyls.)
Because it was discovered so early in the history of paleontology, Pterodactylus suffered the same fate as other "before-their-time" dinosaurs of the 19th century like Megalosaurus and Iguanodon: any fossil that remotely resembled the "type specimen" was assumed to belong to a separate Pterodactylus species or a genus that later wound up being synonymized with Pterodactylus, so at one point there were no less than two dozen named varieties! Paleontologists have since sorted out most of the confusion; the remaining two Pterodactylus species, P. antiquus and P. kochi, are pretty much beyond reproach, and other species have since been assigned to related genera like Germanodactylus, Aerodactylus, and Ctenochasma.
Now that we've sorted all that out, exactly what kind of creature was Pterodactylus? This late Jurassic pterosaur was characterized by its relatively small size (a wingspan of only about three feet and a weight of ten pounds, max), its long, narrow beak, and its short tail, the classic body plan of a "pterodactyloid," as opposed to a rhamphorhynchoid, pterosaur. (During the later Mesozoic Era, some pterodactyloid pterosaurs would grow to truly enormous sizes, as witness the small-plane-sized Quetzalcoatlus.) Pterodactylus is often depicted as flying low over the coastlines of western Europe and northern Africa (much like a modern seagull) and plucking small fish out of the water, though it may also have subsisted on insects (or even the occasional small dinosaur) as well.
On a related note, because it has been in the public eye for well over two centuries, Pterodactylus (in the abbreviated form "pterodactyl") has become pretty much synonymous with "flying reptile," and is often used to refer to the entirely different pterosaur Pteranodon. Also, for the record, Pterodactylus was only remotely related to the first prehistoric birds, which descended instead from the small, terrestrial, feathered dinosaurs of the later Mesozoic Era. (Confusingly, the type specimen of Pterodactylus was recovered from the same Solnhofen deposits as the contemporaneous Archaeopteryx; it's important to bear in mind that the former was a pterosaur, while the latter was a theropod dinosaur, and thus occupied an entirely different branch of the evolutionary tree.)