Eustreptospondylus (meaning "well-reversed vertebrae") was a megalosaurid tetanuran theropod (a large, bipedal meat-eater) about 23-30 ft (7-9 m) long, weighing about 440-550 pounds (200 kg to 250 kg). This predator had a large head, long, sharp serrated teeth, short arms and a primitive hip structure. It lived during the mid-Jurassic period, about 165 million years ago. Incomplete fossils have been found in England. Eustreptospondylus was named by Richard Owen in 1841. The type species is "E. oxoniensis", which was named by C. A. Walker in 1964.