Ancyloceras sp. ammonite fossil from the Volga River, Russia. It has preservation of an iridescent test. Ammonites are extinct marine animals which lived between 380 and 65 million years ago. They are distantly related to the modern-day nautilus. They lived in coastal waters and inland seas. This specimen is from the Aptian stage (about 125 to 112 million years ago) of the Cretaceous period. This specimen measures 40cm in length. Luc Ebbo, Paleogalerie, Salignac.