Abstract
Ammonites and belemnites are among the most celebrated invertebrate fossils, and both groups played a crucial role in the early history of palaeontology. This article gives an overview of the sometimes twisted roads that led from the first descriptions and illustrations of ammonites and belemnites in the 16th century to the picture that emerged in the early 19th century. The pearly Nautilus served as modern analogue for ammonites since the late 17th century, and the organic nature of the ammonites and their kinship to Nautilus became established shortly thereafter. For belemnites, the lack of a suitable modern analogue led to a much longer phase of speculation in which belemnites were assigned to many different groups of organisms, or even to the inorganic/mineralogic world. The apparent lack of both groups in today’s seas led to various explanations including migration into the deep-sea. For ammonites, however, transmutation into the tiny foraminifers seemed at one time a likely explanation. Extinction only became widely accepted after the protozoan nature of the foraminifers was established, and the great deep-sea expeditions failed to recover ammonites or belemnites.
