Taking a Bite Out of a Sauropod Tail

Big, predatory dinosaurs were well-adapted to stripping flesh from bone. That’s obvious from the shape and size of their teeth. What has been more difficult to determine, however, is how they behaved as they ate. Studying bones scored with the toothmarks of carnivorous dinosaurs is one of the most direct ways to approach questions about how predatory dinosaurs fed. One such bone—a tail vertebra of the sauropod Pukyongosaurus found on the Korean peninsula—shows that at least two different predators each had their shot at the same carcass.

The damaged bone is described in an in-press Palaeogeography, Palaeoclimatology, Palaeoecology paper by In Sung Paik and colleagues. The paleontologists report that at least five parts of the bone show toothmarks, including gouges, V-shaped scores and divot-shaped lesions. Since the bones of the sauropod dinosaur were otherwise in good condition—they did not exhibit cracks that would indicate that the bones had been lying on the surface for a long time—Paik and co-authors propose that the dinosaur was rapidly buried near the site of death, meaning that all these toothmarks were made in a narrow window between death and burial. Whether or not the sauropod was killed by a predator cannot be determined. All that is clear is that the toothmarks were left after the Pukyongosaurus died.

So what sort of carnivorous dinosaurs left the tooth marks? That is difficult to say. Most of what is known about big predatory dinosaurs on the Korean peninsula comes from teeth attributed to dinosaurs akin to Allosaurus and tyrannosaurs. Big theropods were certainly around in the right area at the right time, but they are almost entirely a mystery.

Nevertheless, the patterns of the toothmarks indicate a few things about how the predatory dinosaurs ate. Some of the marks, for example, are arranged in parallel rows which indicate that the feeding dinosaur was nipping or scraping with teeth at the very front of the jaw, perhaps at a time when the rest of the easily-accessible flesh had been stripped off. Additionally, while three sets of marks appear to have been made by a large animal, there are two that appear to have been left by a smaller carnivorous dinosaur at a time when most of the flesh had been removed. Were the two dinosaurs of different species? Could they have been an adult and a juvenile of the same species? How much time passed between when the big dinosaur fed and the little one tore off the remaining scraps? No one knows, but the traces left on the sauropod bone provide paleontologists with a murky window into an ancient encounter between predator and prey.

References:

Paik, I.; Kim, H.; Lim, J.; Huh, M.; Lee, H. (2011). Diverse tooth marks on an adult sauropod bone from the Early Cretaceous, Korea: implications in feeding behaviour of theropod dinosaurs. Palaeogeography, Palaeoclimatology, Palaeoecology : 10.1016/j.palaeo.2011.07.002

Riley Black | | READ MORE

Riley Black is the author of The Last Days of the Dinosaurs and many other books. She is a science correspondent for Smithsonian magazine covering fossils and natural history, and she writes about the prehistoric past for a variety of publications.