Could the Chicago Field Museum’s mighty Tyrannosaurus Rex, a dino named Sue, have been toppled by a lowly parasite? According to a recent study in the journal PLoS ONE, a microbe commonly found in pigeons may be responsible for holes in the dinosaur‘s mandible, holes that were previously thought to be bite marks. Paleontologists compared a similar infection in a modern predatory bird to the T-Rex holes and found surprising similarities.
The researchers think the parasite, a protozoan named Trichomonas gallinae, settled in the back of Sue’s throat, and in nine other Tyrannosaurs … studied with similar holes. The parasite caused inflammation that eventually damaged the jawbone [Los Angeles Times], first forming lesions and then eroding the bone away. The inflammation would have choked off the dino’s esophagus, they say, eventually starving the T. Rex to death.
Most researchers have just assumed that the holes were bite marks, but now, the scientists say, they have three pieces of evidence against the bite-wound hypothesis…. First, the holes are generally nicely circular or ovoid, not obviously tooth-shaped. Second, dinosaurs obviously had many teeth, not just one, and the holes don’t seem to come in groups. Third, there are no smaller marks or scrapes on the bone surrounding the holes [Wired.com]. Sue could have caught the parasite from an infected meal or by fighting or mating with another infected T. Rex.
This argument has been made in the past. Other researchers, notably dinosaur anatomy expert Elizabeth Rega of Western University of Health Sciences in Pomona, California, have argued the holes were disease-induced. But Rega’s culprit was a bacteria on the model of actinomyces [Wired.com]. However some scientists have noted that this bacteria does its damage in humans with pus, and since birds, and arguably dinosaurs, don’t create pus, the bacteria probably didn’t create the holes.
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