'Kung Fu Stegosaur' killed with agile strikes of its spiked tail

The wound found in the allosaur fits well with what would result from a stegosaur striking under and upwards with its spiked tail. Fossils of contemporaneous stegosaurs appear to have had unusually flexible and agile tails. Credit: Robert Bakker

Wednesday, October 22, 2014, 1:08 PM - We may have to abandon our idea of the ancient stegosaur as a lumbering giant, and replace it with that of an agile fighter, capable of delivering lethal, precision strikes, like a dino martial artist.

Robert Bakker, the Houston Museum of Natural Science paleontologist who is famous not only for his role in bringing the movie Jurassic Park to life, but in being one of the first to suggest that dinosaurs were warm-blooded and had feathers, has helped make another amazing discovery.

Uncovering the bones of an allosaur - a predator dinosaur from the late Jurassic period - he and his team found evidence of an ancient fight that very likely claimed this dino's life. When examining the animal's fossilized pelvis, they noticed a sizable puncture wound in one of the pubis bones.

"A massive infection ate away a baseball-sized sector of the bone," Bakker and his colleagues said as they presented their findings at the Geological Society of America meeting in Vancouver, B.C. on Tuesday. "Probably this infection spread upwards into the soft tissue attached here, the thigh muscles and adjacent intestines and reproductive organs."

The size and conical shape of the allosaur bone injury closely fits that of the spikes on a stegosaur tail. The stegosaur would have had to wield its tale with great skill to make the deadly blow. Credit: Robert Bakker

According to a Geological Society of America news release, the size and conical shape of the wound matched the tail spike of a stegosaur, "would have required great dexterity to inflict and shows clear signs of having cut short the allosaur's life."

"[Stegosaurs] have no locking joints, even in the tail," Bakker said, according to the statement. "Most dinosaur tails get stiffer towards the end," he added, but apparently stegosaur tails had massive muscles at the base, and fine muscles for control from root to tip.

"The joints of a stegosaur tail look like a monkey's tail," he explained. "They were built for 3-dimensional combat."

According to their research, this wound could only have been inflicted if the stegosaur swept its tail upwards, under the allosaur, while twisting the tip of it to drive the spike in (as they normally point to the side and back). However, Bakker reportedly said that this would have been well within the ability of the stegosaur.

Bakker likened the fight to the one from the 'Rite of Spring" scene from Disney's animated feature Fantasia.

However, whereas the Tyrannosaur (or "beefed up allosaur" according to the GSA) came out the winner of the fight according to Disney, but Bakker isn't so sure that it was due to the predator dino being bigger or stronger.

"I think the stegosaur threw the fight," he said.