This giant fossilised turtle egg – believed to have been laid by a turtle as long as a fully-grown human 90 million years ago – has been found with the embryo still inside.
The tennis ball-sized egg, which is protected by an unusually thick outer shell, was found by a farmer in the Xiaguan Formation of Henan Province in China who sent it to a university for analysis.
The research team, which included scientists from several institutions including the China University of Geosciences (Wuhan), the Henan Geological Museum, and the Royal Ontario Museum, carried out CT-scans on the egg.
The scans revealed that within the thick-fossilised shell, a turtle embryo that was 85 percent developed had been preserved.
Further examination revealed that the embryo inside was probably a member of the Yuchelys nanyangensis turtle species which went extinct 66 million years ago.
Darla Zelenitsky, researcher from the University of Calgary in Canada, said this family of turtle was flat-shelled and developed to live on dry land which was unusual at the time.
Thousands of dinosaur eggs have been found in Henan Province over the past 30 years, however Zelenitsky said they are very rarely found in good condition.
She said: “In comparison with dinosaur eggs, turtle eggs – especially those with preserved embryos – rarely fossilise because they’re so small and fragile.”
Zelenitskythey pointed out that this egg likely survived because of its unusually thick shell which the research team measured at 1.8 millimetres (0.07 inches), four times thicker than the eggs of Galapagos turtles at 0.3 millimetres (0.01 inch).
Judging by the size of the shell the team estimated that it was laid by a turtle with a 5.3-foot-long (1.6 meters) carapace, meaning that from its neck to its tail, it would have been longer than some humans are tall.
Zelenitsky said that part of the shell was broken from the inside so it’s possible that the embryo tried to hatch but didn’t make it and has been trapped in its shell for the last 90 million years.
The Nanhsiungchelyidae is an extinct family of land turtles from the Cretaceous period which were native to Asia and North America.
The study was published online Wednesday (18th August) in the journal Proceedings of the Royal Society B: Biological Sciences.