Strange fossil is the first to show an ammonite without its shell

By Colin Barras

Klug et al. (2021)

Ammonites are among the most common marine fossils from the age of the dinosaurs, but no one has found one like this before. It shows one of the swimming marine molluscs without its distinctive spiral shell – offering a rare opportunity to study ammonite internal anatomy.

On a first look, Christian Klug at the University of Zurich, Switzerland, and his colleagues struggled to make sense of the fossil. “I wasn’t very sure what was what,” he says. Although the researchers could instantly recognise the shield-shaped structure on the left …