"The question then arises, 'Did it die because of the infection?' We cannot tell. But it probably was a contributing factor," Reisz said. (Source)The study is detailed online in the journal Naturwissenschaften - The Science of Nature.
"It looks like the animal broke its tooth and because it doesn't replace its tooth, that became a hole — and through that hole, oral bacteria probably entered the inside of the jaw and then gradually the jaw was closed up," Reisz told LiveScience. He added that it was likely a pretty bad infection. "The infection raveled about four or five teeth into the area where the jaw is quite thin, and that's where it went into the mouth area and the outside of the jaw," Reisz said. "As a consequence, that area of the jaw is really damaged." (Source)
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