Big tail muscle made dinosaur speedy

EDMONTON, Alberta, Oct. 14 (UPI) -- A meat-eating dinosaur preying on plant-eating neighbors in South America was a lot faster, and so deadlier, than first thought, a Canadian researcher says.

Scott Persons of the University of Alberta said the 23-foot-long Carnotaurus had a huge tail muscle he believes made it one of the fastest-running hunters of its time.

A close examination of fossil tail bones of Carnotaurus showed its caudofemoralis tail muscle had a tendon that attached to its upper leg bones that pulled the legs backward powerfully to give the carnivore more power and speed in every step, a university release reported Friday.

Using 3-D computer models, Persons determined the tail of Carnotaurus had a series of tall rib-like bones that interlocked with the next pair in line, supporting the huge muscle.

The interlocked structure of the tail did present one drawback: the tail was rigid, making it difficult for the hunter to make quick turns.

However, Persons said, what Carnotaurus gave up in maneuverability it made up for in straight-line speed.