Paleontologist Robert Bakker believes that the spiky tail of the stegosaurus was used as a defensive weapon
Paleontologist Robert Bakker believes that the spiky tail of the stegosaurus was used as a defensive weaponRobert Bakker

The stegosaurus was not the slow-witted creature previously thought, but a ferocious fighter capable of killing even predatory dinosaurs, according to new research.

Scientists have discovered fossil evidence of a dinosaur which was attacked and killed by a stegosaur, according to a Mail Online report.

A predatory allosaur was found to have a fatal stab wound to its pubis bone. The laceration was in the conical shape of a stegosaur tail spike, called a thagomizer, by paelontologists.

"A massive infection ate away a baseball-sized sector of the bone," said Houston Museum of Natural Science paleontologist Robert Bakker.

"Probably this infection spread upwards into the soft tissue attached here, the thigh muscles and adjacent intestines and reproductive organs."

At a meeting of the Geological Society of America in Vancouver Bakker and his colleagues revealed their findings. The absence of any healing suggests the allosaur died from the infection, they claim.

The wound inflicted by a powerful stegosaur tail would have been similar to those seen in goring accidents during bull runs.

To inflict a fatal wound, the stegosaur would need great flexibility and strength in its tail. Bakker believes that the joints of a stegosaur tail had the suppleness and looked like a monkey's tail.

Skeletal evidence from fossil stegosaurs suggests their tails were more dextrous than most dinosaur tails. "They have no locking joints, even in the tail," Bakker explained. "Most dinosaur tails get stiffer towards the end."

Previously, paleontologists thought the spiky tail was purely for decoration, but in 2005, researchers reported that a non-fatal wound found in the fossil of an allosaur, was most likely inflicted by a stegosaur tail.

A report in the Smithsonian.com concluded that the tail with four long spikes would most likely slash open wounds if an attacking animal was standing parallel to the stegosaurus.

The twenty-foot long stegosaurus lived during the late Jurassic period, about 150 million years ago. Its name means 'roofed lizard,' stemming from paleontologists believing that this dinosaur's plates lay flat along its back, like a form of armour.

What the four-ton Stegosaurus had in muscle power, it lacked in intellect, as it possessed an unusually small brain, about the size of a walnut.