Posted on behalf of Ana Belluscio

Eight insect cocoons found inside a broken titanousaur egg are shedding light on a surprising food chain in the Cretaceous period, more than 70 million years ago.

According to a paper published this week in Palaeontology, the cocoons belonged to a cretasic wasp, Rebuffoichnus sciuttoi, which presumably fed on rotting dinosaurs’ eggs.

“We believe that wasps nested inside the egg to either predate on scavenger insects eating the egg’s remains, or on spiders feeding on scavengers”, says Jorge Genise, lead author of the paper and a researcher at the Argentine Museum of Natural Sciences.

The clutch of five eggs was found in 1989 in the Argentinean Patagonia, and after identification investigators attributed them to titanosaurs, a group of sauropod dinosaurs that include some of the biggest animals ever to live on Earth. In 2007, investigators discovered in one of the eggs eight fossilized cocoons. While one of the cocoons was intact, the remaining seven had only one rounded end, indicating that wasps might have emerged from the other. The egg also showed cracks that suggested it had been crushed, exposing the content to scavengers.

Although wasp cocoons have previously been reported near dinosaurs’ nesting sites , this is the first time that wasp cocoons have been found inside dinosaur eggs

“Dinosaurs nested over and over in the same place, so-called nest site fidelity,” explains Genise. “This is an evidence that there was a community of scavengers related to eggs that cleaned up the sites.”

Image: Sarzetti