47 million years old… and still doing it (Image: Senckenberg Naturmuseum Frankfurt)

What a way to go. Some 47 million years ago, these turtles clung to each other as they mated in a German lake. Now fossilised, the members of this species are the only known examples of vertebrates fossilised during copulation.

The turtles (Allaeochelys crassesculpta, now extinct) have been excavated from the Messel Pit, a disused quarry that was once a volcanic lake and is now a rich source of fossils. Fifty-one specimens of A. crassesculpta have been found there, including six pairs.

Having shown that each pair is made up of a male and female, Walter Joyce of the University of Tübingen in Germany and colleagues have now confirmed what palaeontologists long suspected – that all six pairs were mating when they died. Males can be distinguished from females because they have a longer tail that protrudes beyond their shells.


What killed the turtles, leaving them in this eternal embrace? Joyce thinks that the volcanic activity beneath the lake meant that poisonous gases like carbon dioxide seeped up though the lake bed, turning the bottom of the lake into a toxic bath.

Like their modern descendants, many millions of years later, A. crassesculpta probably initiated mating at the surface and sank as they copulated. But at Messel Pit, 47 million years ago, that became a fatal act.

Journal reference: Biology Letters, DOI: 10.1098/rsbl.2012.0361