Messel

Abstract The Messel Pit, located near Frankfurt am Main, Germany, is inscribed on the list of UNESCO World Heritage sites due to the breathtaking quality of its fossils and the wealth of detail they reveal about life in an ancient ecosystem. Its age, about 48 million years old, places it in the last sustained greenhouse phase of Earth's climate, the Eocene. Fossils of most major terrestrial groups of organisms are preserved together, from freshwater algae to fungi, plants and animals. Species diversity in many groups is higher than in the same area today. Extraordinary details of organismic anatomy are preserved, from iridescent insect colouration to bird plumage and reptile scales. Furthermore, stunning specimens record organismic interactions, from predator–prey relations to reproductive behaviour. Messel arguably holds the greatest promise to elucidate a terrestrial ecosystem in a greenhouse climate. Key Concepts Messel is an ancient maar lake that resulted from volcanic eruptions 48 Ma. Climate at the time was warm and equable, a so‐called ‘greenhouse climate’. The sediment in which the fossils are preserved is an ‘oil shale’ with a high water and organic content. A special transfer method developed in the mid‐twentieth century made possible the long‐term conservation of vertebrate fossils from Messel. Messel preserves an exceptional taxonomic range of fossils, from algae to plants and animals. Soft‐tissue preservation at Messel gives unparalleled insight into the anatomy of ancient organisms. Extraordinary specimens from Messel document organismic interactions, from trophic relations to reproductive behaviour.