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This pathology on the bone Paul is holding could have been caused by an old injury when alive. It could be from an infection, injury, or bite from a predator. There may be a tooth tip embedded in it, leading one to beleive it is from a predator bite. At any rate, the wound healed over, and the Triceratops lived on to see another day.

To the right is a tooth tip from the Triceratops.