World’s oldest dinosaur eggs reveal more about reproductive behaviour

January 26, 2012 – Matt van Onselen

The world’s oldest fossilised dinosaur eggs, discovered in the Free State back in 1976 and displayed at Maropeng a short time ago, have allowed scientists to draw significant conclusions about dinosaur reproductive behaviour. The findings have been announced in a new article in the international journal, Proceedings of the National Academy of Sciences.

The eggs are a staggering 195-million years old and have been housed at the Bernard Price Institute (BPI) at the University of the Witwatersrand. Professor Bruce Rubidge, director of the BPI, says the fossils are extremely rare. “Nesting eggs are not abundant around the world,” he says. “Nothing is as old as the South African fossil eggs – they predate any others by 60-million years.”

Rubidge says there is more to these fossils than just the eggs. “These nest reserves were found with footprints and other features that tell us a great deal about dinosaur behaviour.” Scientists have paid careful attention to all available evidence. The fossilised footprints, for example, suggest that offspring remained at the nesting site until they grew significantly larger.

Other evidence provides information about the behaviour of the adults. The manner in which the fossilised eggs were lying suggests that the mother took time to arrange them once they were laid. The nest was also compared to other nests found nearby, and scientists have concluded that the parent dinosaurs visited the same nest repeatedly, which is called “nesting site fidelity”.

The clutch of dinosaur eggs were discovered in Rooidraai (red corner, named after the colour of the rock in the area) in the Golden Gate Highlands National Park, by the former director of the BPI, Professor James Kitching, while he was looking through scree from a blasting. On closer inspection while preparing the fossils, Kitching saw there were tiny, delicate embryonic remains in two of the eggs. He stopped preparations immediately as he felt the embryonic remains were too delicate and fragile to be tackled by any South African fossil preparatory lab.

This isn’t the last we’ll hear about the discoveries, says Rubidge. “It’s the beginning of a really exciting chapter. We can see what the benefits of a long-term excavation of the site would be.”

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