Ammonoids, commonly known as ammonites, represent a fascinating subclass of cephalopod molluscs that inhabited the world’s oceans for millions of years. Their presence in the geological record spans from the Devonian period, approximately 400 million years ago, to their final extinction at the end of the Cretaceous period, some 65.5 million years ago. These marine organisms are key to palaeontological science due to their rapid biological evolution and vast global distribution.
These characteristics make them excellent index fossils for dating rock formations, enabling researchers to construct biozone sequences with exceptional biostratigraphic precision. In the fields of collecting and geology, high-quality specimens from specific sites in Peru are particularly noteworthy. These specimens are of considerable size, reaching a diameter of approximately 8 cm, allowing for a detailed appreciation of the structure and beauty of these ancient inhabitants of the seas.
Size: approx. 8 cm.
