Messel Pit fossils

The Messel Pit, near Darmstadt in Germany, is a former oil shale quarry that preserves a lake from about 47 million years ago. Its fine, oxygen-poor mud entombed whole animals so well that fur outlines, feather colour structures, skin and even the last meal in the stomach survive. It was listed as a UNESCO World Heritage Site in 1995 after local campaigners helped halt plans to turn it into a landfill.¹²³

At the time the region sat in a warm, wet subtropical forest around a volcanic crater lake, in the hothouse that followed the Paleocene-Eocene Thermal Maximum. Poisonous gas from the lake may have killed animals that came to drink or flew overhead and fell in. The fossils include early horses such as Eurohippus (some mares with a foetus inside), early bats with insects in their stomachs, a crocodile, turtles, birds, insects and an early primate called Darwinius masillae, nicknamed Ida, discovered in 1983 and presented to the public in 2009.³

Messel gives a rare, detailed snapshot of a whole ecosystem soon after mammals took over the land, and a hundred years of digging have yielded tens of thousands of specimens. Stomach contents show what each animal ate, so researchers can reconstruct food webs. It also shows that Europe, then a chain of islands, held mammal groups quite unlike those of today, including the ancestors of horses and the earliest well-preserved bats.¹³