Scientists published their findings in a report in Biology Letters
entitled "Caught in the act: the first record of copulating fossil vertebrates."
They report that in the Eocene Messel Pit
,a fossil-rich disused quarry and Unesco World Heritage site, they discovered "numerous pairs of the fossil carettochelyid turtle Allaeochelys crassesculpta that represent for the first time among fossil vertebrates couples that perished during copulation."
reported that researchers conclude the copulating turtles had initiated sex on the surface of the sites lake and then sank as they were overcome by toxic volcanic gases. They were then buried in the lake-bed sediments.
Walter Joyce of the University of Tuebingen in Germany said
of the turtles: "They were obviously so enthralled that they sank into deeper, poisonous water and died. They were in exactly the position that turtles adopt while mating."