Smithsonian.com

In 1971, a team of Polish and Mongolian paleontologists discovered a spectacular pair of dinosaurs in the Cretaceous strata of the Gobi Desert. A Protoceratops and Velociraptor, the herbivore and carnivore were locked together in a lethal embrace and came to be known as the “Fighting Dinosaurs.” We will never know exactly what happened in the moments prior to their deaths, but the two appear to have been entombed as they tussled.

Now paleontologists in the United States are proposing that they have found a different example of a predator and potential prey in the same Cretaceous grave. In a series of YouTube videos, preparator Chris Morrow, self-described “Dino Cowboy” Clayton Phipps, Black Hills Institute paleontologist Peter Larson and Houston Museum of Natural Science curator Robert Bakker present the remains of two dinosaurs—a ceratopsid and a tyrannosaurid—found in the famous Hell Creek Formation. Both dinosaurs are being cleaned up and readied for study at CK Preparations in Fort Peck, Montana, where the videos were shot.

Exactly what the two dinosaurs are is unclear. The skull of the horned dinosaur looks very much like a large Triceratops, and the smaller tyrannosaurid looks like a juvenile Tyrannosaurus. But Larson and Bakker think otherwise. In one video, Larson points out a number of ambiguous features he suggests distinguish the horned dinosaur from Triceratops. In another video, Bakker describes features of the tyrannosaurid’s arm as vastly different from Tyrannosaurus. He and the others in the room identify the tyrannosaurid as Nanotyrannus, a controversial genus that Bakker named and Larson has supported. The specimens are spectacular in terms of their completeness and preservation, but whether or not they represent unknown or little-known genera of dinosaurs that lived alongside Triceratops and Tyrannosaurus is presently unclear. A solid understanding of dinosaur growth and variation will be needed to tell whether these dinosaurs are actually all that different from what has been found before.

So why are these two being called the “dueling dinosaurs”? At one point in the video, the assembled crowd wonders why the tyrannosaurid skull appears to be crushed. Clayton Phipps suggests that the predator was kicked in the head by the ceratopsid dinosaur right before both became buried. (Peter Larson supports this view in another video.) That may be, but we can’t use proximity alone to determine why these dinosaurs were found together.

The question is one of taphonomy: What happened between the deaths of the animals, their burial and their eventual discovery? Have paleontologists truly caught a tyrannosaurid in the act of trying to take down a ceratopsid, or is there some other explanation—such as a catastrophic local flood, or some sort of mire that trapped them—for why the two dinosaurs were found together? Think about the pose of the tyrannosaurid—the dinosaur is in the classic “death pose” with the head thrown back and tail arched up. Previous studies have indicated that this pose might be caused by death throes associated with a lack of oxygen reaching the brain, or, more simply, by immersion in water. If the tyrannosaurid had died after being kicked in the face by the ceratopsid, I would expect the body to be slumped over or otherwise in a different position. More research is needed. Speculating and coming up with hypotheses is fun, but a detailed understanding of geology and the prehistoric environment these animals died in is required to know whether we can truly call them “dueling dinosaurs.”

Still, the two dinosaurs look like they are fairly complete and well-preserved. Together they will almost certainly provide some new information about two of the most famous dinosaur lineages present in the Hell Creek Formation. We’ll just have to wait for the research to be completed before we can tell whether the more sensational elements of the story are true.