Stegosaur Delivered Fatal Stab Wound to Allosaur

Posted on October 22, 2014

Scientists have discovered evidence that a stegosaur delivered a fatal blow to an allosaur with its tail spike. Stegosaurs were large plant eaters but they had large spiked tails that could be used to defend themselves against predators like allosaurs. The tail was a very impressive weapon that the stegosaur had great control of.

Evidence of a stab wound in the pubis bone of an allosaur was presented by Houston Museum of Natural Science paleontologist Robert Bakker and colleagues at a meeting of the Geological Society of America in Vancouver, B.C. The allosaur pubis bone has a large conical shaped hole it in. This hole is the shape of a stegosaur tail spike. The researchers say it would have required great dexterity for the stegosaur to land the fatal blow. Bakker released the above illustration showing what the stegosaur's attack on the allosaur might have looked like. The image below shows the entry wound on the allosaur bone.

The researchers say there is evidence the wound cost the allosaur its life. There are signs of an infection at the wound site. The researchers also say that the fact the wound lacks signs of healing indicates the allosaur died from the wound.

Bakker says in a statement, "A massive infection ate away a baseball-sized sector of the bone. Probably this infection spread upwards into the soft tissue attached here, the thigh muscles and adjacent intestines and reproductive organs."

Bakker says the stegosaur's tail was "built for 3-dimensional combat." He compares the joints in the tail to a monkey's tail and says the stegosaur would have had fine muscle control all the way to the tip of the tail. Stegosaurs also had huge muscles at the base of their tails. They were certainly able to defend themselves against allosaurs. However, they may not have been very smart so it is possible allosaurs could get the upper hand with a clever attack or by working in groups. Bakker says in a release that "stegosaurs had among the smallest brains for its body size of any large animal, ever."

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