Detailed Douvilleiceras Cretaceous Ammonite

Description: This fine ammonite is Douveilliceras mammilatum from Madagascar which has much of the original shell present. The lack of acidity in the depositional environment allowed them to be preserved as you see it here. Notice the tubercles present on this example. Members of the genus are found with spines, tubercles, or knobs, and are thought to be indicative of a hostile environment in which such structures were necessary as a defense. Notice the intricate suturing pattern seen where the shell is missing, allowing you to see how the ammonite’s shell was reinforced with small impact upon its weight, and important factor for an animal which needed to move freely within the water column in pursuit of prey.