Its classification has proved difficult. The vertebrae were originally assumed to be linked with some theropod teeth and the result named Altispinax dunkeri, a species of the Superfamily Megalosauroidea. Later this assignment was shown to be unjustified, as the vertebrae identified as belonging to a new species of Acrocanthosaurus, Acrocanthosaurus altispinax, by Gregory Paul. In 1991 it was reassigned to a new sinraptorid genus, Becklespinax, by George Olshevsky, in honour of its discoverer, Beckles. The type species is B. altispinax.
This animal was probably on the order of 8 m (26 ft) long and 1.5 tonnes (1.5 tons) in mass.
The humped Megalosaurus in Crystal Palace, London
The hump on the back of the Megalosaurus sculpture in Crystal Palace and other restorations from the 19th century was based on the material now referred to as Becklespinax.
Three Becklespinax altispinax back vertebrae from Sussex have irregular rugosities "over the distal third of the neural spines." The two spines closest to the skull are ankylosed. The single closest spine is only about two-thirds the height of the others.
It was thought that the third Becklespinax vertebra's spine was shorter because of breakage. However, the discovery of a vertebral fin incorporating only two vertebrae in Concavenator provides evidence that the short Becklespinax spine may be complete.