London: A giant dinosaur - as long as a double decker bus - that lived about 72 million years ago had a brain just 6.3cm big, say UK scientists who have described one of the most complete sauropod dinosaur braincases ever found in Europe.
The finding could help scientists uncover some of the mysteries of how dinosaur brains operated, including their intellectual and sensory abilities.
Researchers have digitally reconstructed the cavity where the brain lay, the passages of the cranial nerves and certain blood vessels as well as the labyrinth of the inner ear.
The work was done by a team led by a senior research fellow Dr Fabien Knoll from The University of Manchester.
Skulls, and particularly the braincases, are very fragile so not many have survived. That is not the case with this find, which is remarkably complete.
The skull, from a titanosaur, a type of sauropod, was found at a dig site in eastern Spain in 2007 and experts have spent the last few years studying it, 'mirror.Co.Uk' reported.
"This is such a rare finding that is why it is so exciting. Usually we find vertebrae or other bones, very rarely the braincase and this one is complete," Knoll said.
"Currently we know very little about the brain of dinosaurs. Research such as this is fundamental if we want to get an idea about the cognitive skills of these animals or if they had keen hearing or good eyesight and plenty of other information," Knoll said.
The titanosaur lived about 72 million years ago. Like all sauropods it was four-legged with a long neck and a long tail and herbivorous.
It was a distant relative of Diplodocus but, with about 14m in length, was only half its size. The study shows that its brain fitted in a diminutive cavity of only 6.3 cm in length.
Knoll, who made the first digital reconstruction of a dinosaur endocranial cavity in the late 1990s, said: "In a few years' time if more finds like this come to light and, above all, if they are studied with the modern imaging technologies then we could really start to understand more about dinosaur brains."