From petrified snakes, through giant ‘foraminifers’, to extinct cephalopods. The early history of ammonite studies in the Italian peninsula

As a result of their intrinsic beauty and relative abundance in some Mesozoic deposits, ammonites have always attracted the attention of scholars and curious people, with written testimonies that can be traced back to Pliny’s Naturalis Historiae of 75 AD. The mysterious and evocative charm enclosed behind these extinct cephalopod has made its influence felt on legends, myths, necromancy, medicine, religion and literature, attracting the literary interest of authors such as Goethe, Scott, Schiller and Salgari. Of particular interest is the evolution of scientific thought and interpretations that, over time, have groped to find a place for these ‘difficult fossils’, suspended between the organic world and the stone. In the present work, I briefly discuss the history of the study of ammonites in the Italian peninsula, during the period between the sixteenth and the late nineteenth centuries. Initially interpreted as petrified snakes, and believed for a long time to be ‘giant’ ancestors of living and extinct foraminifera, only in the nineteenth century, ammonites were definitively interpreted as extinct cephalopods, with the recognition of their crucial importance for biostratigraphy.