Eternal embrace

These are the first known fossils of vertebrate couples that perished in flagrante delicto. Image: Senckenberg Research Institute

 The fossils found in Germany are the first known example of prehistoric sex.

Forty-seven million years ago, turtles of the extinct species Allaeochelys crassesculpta were mating near a volcanic crater lake. Their sweet embrace didn’t last long: they were buried in lakebed sediments — their love forever locked in geological time.

 

The researchers led by Dr Walter Joyce of the University of Tübingen found the fossilised star-crossed lovers at the Messel Pit Fossil Site in Germany. They think that the turtles initiated coitus in the surface waters of Messel Lake and slowly sank into deeper waters. “[They] perished when their skin absorbed poisons while sinking into toxic layers,” wrote the researchers in a paper published in the journal Biology Letters.

Messel Pit is a UNESCO World Heritage Site famous for the fossil animals and plants preserved in Eocene black oil shale.  In the past three decades, researchers have found more than 51 specimens of this turtle; 12 of them are preserved in pairs. However, out of the twelve preserved pairs, only seven were caught in the act of mating.

One of the seven fossils caught in the act of mating. Image: Naturmuseum Senckenberg in Frankfurt

“We demonstrate for the first time that all couples contain one male and one female individual and that the tails of some males are aligned with those of the female,” wrote the researchers. “We confirm that these animals indeed perished while mating and that they are the only known vertebrate fossil to be preserved in the act of mating.”

A. Carettochelys females measured 20 to 25 centimetres; the males were up to 17 per cent smaller. They thrived during the Eocene, and they were rather similar to the pig-nosed turtle (Carettochelys insculpa) that lives in New Guinea and Australia.

Source: Biology Letters

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