Cassiope’s colours

This is a small, remarkably well-preserved gastropod of the genus Cassiope. The beautiful turriculate shell was discovered in Edelbach, Austria, in a fossil site dated to around 90 million years ago. The colourful pattern it sported when alive is revealed under ultraviolet light. Almost undetectable to the naked eye, it is arranged in several rows of spots: the pale areas (white and light yellow) correspond to the parts that contained a high concentration of pigments, the composition of which remains to be discovered; while the dark areas (grey, green and bluish) were less rich in pigments. In the animal world, colour can have various adaptive functions, such as camouflage, warning of predators, intraspecies communication, etc. In molluscs such as gastropods and bivalves, fossils are the only materials that can provide data about the evolution of their colour over millions of years. This image is a winner of the 2021 La preuve par l'image (LPPI) competition.