Rhamphorhynchus (ˌræmfəˈrɪŋkəs, from Ancient Greek rhamphos meaning "beak" and rhynchus meaning "snout") is a genus of long-tailed pterosaurs in the Jurassic period. Less specialized than contemporary, short-tailed pterodactyloid pterosaurs such as Pterodactylus, it had a long tail, stiffened with ligaments, which ended in a characteristic soft-tissue tail vane. The mouth of Rhamphorhynchus housed needle-like teeth, which were angled forward, with a curved, sharp, beak-like tip lacking teeth, indicating a diet mainly of fish; indeed, fish and cephalopod remains are frequently found in Rhamphorhynchus abdominal contents, as well as in their coprolites.
Although fragmentary fossil remains possibly belonging to Rhamphorhynchus have been found in England, Tanzania, and Spain, the best preserved specimens come from the Solnhofen limestone of Bavaria, Germany. Many of these fossils preserve not only the bones but impressions of soft tissues, such as wing membranes. Scattered teeth believed to belong to Rhamphorhynchus have been found in Portugal as well.
The classification and taxonomy of Rhamphorhynchus, like many pterosaur species known since the Victorian era, is complex, with a long history of reclassification under a variety of names, often for the same specimens.
The first named specimen of Rhamphorhynchus was brought to the attention of Samuel Thomas von Sömmerring by the collector Georg Graf zu Münster in 1825. Von Sömmerring concluded that it belonged to an ancient bird. When further preparation uncovered teeth, Graf zu Münster sent a cast to Professor Georg August Goldfuss, who recognised it as a pterosaur. Like most pterosaurs described in the mid 19th century, Rhamphorhynchus was originally considered to be a species of Pterodactylus. However, at the time, many scientists incorrectly considered Ornithocephalus to be the valid name for Pterodactylus. This specimen of Rhamphorhynchus was therefore originally named Ornithocephalus Münsteri. This was first mentioned in 1830 by Graf zu Münster himself.