Auca Mahuevo

The sedimentary deposits in eroded badlands at Auca Mahuevo in the Patagonian province of Neuquen, Argentina, are among the paleontologist's rare lagerstätten, the undisturbed strata that give glimpses of a range of ecology at a given moment in the Earth's history. The sedimentary layers at Auca Mahuevo were laid down 80 million years before present and offer an unequalled view of a fossilized titanosaurid sauropod hatchery.

At Auca Mahuevo dinosaur eggs containing identifiable embryonic remains have been the most spectacular discoveries. The eggs retain casts of the membrana testacea, the internal membrane that adheres to the shell, familiar to anyone who has peeled a hard-boiled egg. The context revealed a vast rookery of excavated nest structures that can be compared to living egg-layers such as turtles, crocodilians and birds. Even their spacing within the nesting locality (two to three meters apart) can be assessed. Reconstruction of nesting strategies suggest that shallow pits with rims were excavated and plant material incorporated in the surface.

The Auca Mahuevo lagerstätte was discovered in two expeditions, in 1997 and 1999, by Luis Chiappe, Lowell Dingus, and Rodolfo Coria, who were looking for fossilized birds. the site is now officially protected, but looted eggs are coming into the market.

External references

 * Eggshell abnormalities at Auca Mahuevo
 * Nesting strategies
 * BBC h2g2 site: Auca Maheuevo