An advanced member of the largest group of dinosaurs ever to walk the Earth, had a relatively tiny brain, researchers have claimed.
The scientists analysed the skull of 70-million-year-old fossils of the giant dinosaur Ampelosaurus, discovered in 2007 in Cuenca, Spain, in the course of the construction of a high-speed rail track connecting Madrid with Valencia.
The reptile, which was sauropod, long-necked, long-tailed herbivores, were the largest creatures ever to stride the Earth.
More specifically, Ampelosaurus was a kind of sauropod known as a titanosaur, many, if not all of which, had armour-like scales covering their bodies
Sauropod skulls are typically fragile, and few have survived intact enough for scientists to learn much about their brains.
By scanning the interior of the skull via CT imaging, the researchers developed a 3-D reconstruction of Ampelosaurus' brain, which was not much bigger than a tennis ball, CBS News reported.
"This saurian may have reached 49 feet in length; nonetheless its brain was not in excess of 3 inches," study researcher Fabien Knoll, a paleontologist at Spain's National Museum of Natural Sciences, said.
The first sauropods appeared about 160 million years earlier than this fossil
For years, scientists have wondered how the largest land animals ever lived with such tiny brains.
Their computer model also revealed the ampelosaur had a small inner ear.
The findings are published online in the journal PLOS ONE.