Abstract
A statistical and morphological study of the pterosaurRhamphorhynchusfrom the Solnhofen Limestone of Germany shows that specimens fall into discrete size-classes that are year-classes resulting from seasonal mortality or preservation of specimens. Taxonomic characters used in the past to separate species ofRhamphorhynchusare all related to size and ontogeny, and all specimens belong to a single species,R. muensteri.Thus, the collections ofRhamphorhynchusprovide an unequaled record of the growth and development of a Jurassic rhamphorhynchoid pterosaur.Rhamphorhynchusdid not have rapid determinate growth; the growth rate was comparable to that of extant crocodilians, and growth continued over the course of at least three years after individuals began to fly.