Amaltheus is an extraordinary ammonite, being extremely flat and discus-like. This example has had the shell removed to reveal the complex suture lines underneath. You can see the chambers between them which are filled with calcite crystal and, towards the end, mud. The ammonite is far from complete; the body chamber (the long chamber that takes up over half of the outer whorl) is completely missing – we know this because there are suture lines right to the end of the fossil. Check out other examples of Amaltheus to see just how different this specimen is.
Find out more about ammonites on the molluscs pages.