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A silhouette of the dinosaur Nemegtomaia barsboldi, indicating the dinosaur's bones and the nest it was sitting on. Much of the skeleton was lost to beetles. Reconstruction by Marco Auditore, from Fanti, et al. 2012.

What dinosaurs ate is a never-ending source of fascination. This is especially true for carnivores—if basic cable documentaries are any indication, we simply can’t get enough of flesh-tearing theropods. But even the largest and most vicious dinosaurs were just one point in complex food webs. The world’s most formidable consumers eventually became food themselves. Among the animals which fed on dinosaurs were beetles.

Just as carcasses attract a variety of scavenging insects today, the same would have been true during the time of the dinosaurs. Sadly, we don’t have direct evidence for most of these interactions, but some beetles left clues in the bones of dinosaurs. Some skeletons have been found with trails and holes plowed into the bone. These patterns are similar to the damage created by some types of modern dermestid beetles. These insects are scavenging specialists, and while fur, feathers, skin, and soft tissues are their preferred foods, they will sometimes dig into bone, too. Beetles have been doing this for tens of millions of years. Beetle-damaged bones have been found in everything from Pleistocene mastodons to Cretaceous dinosaurs such as Protoceratops.

The latest dinosaur to be added to the list of beetle food is Nemegtomaia barsboldi. This was one of the many oviraptorid dinosaurs in Late Cretaceous Mongolia, one of the small, feather-covered, beaked theropods that were relatively closely related to dinosaurs like Velociraptor. As reported by paleontologists Federico Fanti, Philip Currie, and Demchig Badamgarav in PLoS One, a partial skeleton of a Nemegtomaia found on top of a nest was significantly damaged by insects similar to dermestid beetles. The joints of the dinosaur’s left arm and leg were obliterated by insect damage, and beetle bore holes can be seen in the left side of the skull.

Lest anyone imagine a nightmarish, B-movie scenario, the beetles did not overtake the dinosaur while it was alive. According to Fanti and co-authors, it appears that the dinosaur was only partially buried after death. This left significant portions of the body, from the neck to the hips, exposed to a variety of scavengers. Small mammals may have gnawed at the body, but the beetles did the most damage. The beetles probably ate whatever dried skin and tissue remained before destroying many of the thinner bones. Most of the body was lost by the time the dinosaur was finally interred.

References:

Fanti, F., Currie, P., & Badamgarav, D. (2012). New Specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia PLoS ONE, 7 (2) DOI: 10.1371/journal.pone.0031330