Thursday, October 1, 2009

Who Killed T-Rex?

A QUANTUM OF SCIENCE

The King of the Dinosaurs may have been done in by a microscopic parasite

When paleontology researchers from major universities and museums around the world started to compare notes on the bone structures of particular specimens, they noticed something strange: cavities. In specific, Tyrannosaurus Rex cavities. Of the 61 specimens examined, 15% had significant lesions in the mandible (jaw bone), most of them occurring on both sides of the jaw. The earlier interpretation – that these were the result of intraspecies predation – was ruled out by comparison to the jaws of crocodiles, which form significant scar tissue when punctured by the teeth of other crocodiles. There was no sign of scarring, the cavities were simply eroded into the jaw bone, characteristic of a microbiological agent.

Researchers concluded that based on the similarities between the morphology and pattern of lesions in the T-rex specimens to those found in modern falcons, a protozoan known as Trichomonas gallinae was most likely responsible. The protozoan could have been transmitted either from infected prey or through violent contact between T-rex muzzles such as might be imagined in instance of either displays of dominance or outright cannibalism. Once the disease progressed to the stage found in many of the examined fossil specimens, feeding would become problematic or even impossible. In another modern equivalent, the Tasmanian Devil is actually starving itself into extinction following a face-biting behavior that spreads an oral cancer between individuals. While not conclusive in their theory that trichomonosis starved the T-rex to death, evidence is accumulating that it may have been the case for some populations of the dinosaur, and the potential exists that scientists may be able to extract DNA from these fossils and provide a more solid conclusion in the near future.

For more information:

Common Avian Infection Plagued the Tyrant Dinosaurs (Wolff et al)

Trichomonas gallinae (Wikipedia)

© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

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