WASHINGTON (AFP) — A group of US paleontologists said last Friday it has unearthed a new species of dinosaurs standing some six feet tall and weighing up to 4.5 tonnes, with the longest horns of all.

The 72-million-year-old herbivore, now named Coahuilaceratops magnacuerna, has two large horns above its eyes measuring up to an impressive four feet (1.22 meters) long -- the largest of any other species, providing fresh insight into the history of western North America.

Scientists uncovered fossils belonging to both an adult and a juvenile of the rhino-sized tubby creature at the Cerro del Pueblo Formation in Coahuila, Mexico. It measured about 22 feet (6.7 meters) long as an adult, standing six to seven feet (1.8 to two meters) tall at the shoulder and hips.

“We know very little about the dinosaurs of Mexico, and this find increases immeasurably our knowledge of the dinosaurs living in Mexico during the Late Cretaceous,” said the study's lead author Mark Loewen, a paleontologist with the Utah Museum of Natural History.