Eggshells preserve elephant bird DNA

U. SHEFFIELD (UK)—Well-preserved ancient DNA has been found in the fossil eggshells of the extinct elephant bird of Madagascar, the heaviest bird known to have existed.

Mike Parker Pearson, professor of archeology at the University of Sheffield, discovered the eggshells whilst researching in Madagascar. He says the 19,000-year-old eggs of Aepyornis are an excellent source of DNA, especially when found in warmer climates.

Aepyornis weighed about half a ton and, like an outsized ostrich, stood nearly 3m high. Its eggs are the largest bird eggs ever known, with a capacity of 11 litres—equivalent to 180-240 chicken eggs or seven ostrich eggs.

Findings are published in the journal Proceedings of the Royal Society B.

Parker Pearson found many of the bird’s nesting sites and some of the human settlements where the giant eggs were re-used as containers for liquids in the coastal dunes of southern Madagascar.

The team radiocarbon dated the fossil eggshells and say their chemical composition can be used to shed light on past environments. This new study will enable a DNA profile to be produced, Parker Pearson says.

Most of the birds appear to have died out before AD 1000, when a lost civilization emerged in the south of Madagascar, with long-distance trade contacts to Africa’s Swahili coast, the Persian Gulf and China.

By the time that this civilization flourished, in the 11th-13th centuries, the elephant bird’s numbers were in decline, most likely linked with human population growth.

They most likely became extinct around 1650, when a French colonist described them as living in the most remote places and too difficult to catch.

“This mysterious bird was probably the inspiration behind stories in the Thousand and One Nights and as told by Marco Polo,” says Parker Pearson. “It’s amazing that we now know so much about its genetic make-up, its diet, and its habits. Sadly, it seems to have been yet another casualty of human population growth.”

“Researchers have tried unsuccessfully to isolate DNA from fossil eggshell for years,” says team member Charlotte Oskam, a doctoral student at Murdoch University in Western Australia.

“It just turned out that they were using a method designed for bone that was not suitable for fossil eggshell.”

The team now plans to study eggshells from a number of archeological sites in New Zealand to investigate how humans interacted with another giant bird, the moa, which became extinct 600 years ago due to hunting pressures.

Researchers from the University of Oxford, Murdoch University in Australia and the University of Western Australia, and Canterbury University and Otago University in New Zealand, the University of Colorado in the United States, and Copenhagen University in Denmark contributed to the study.

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