Researchers, in a recent report published on Tuesday, revealed that they have found a new species of plant-eating dinosaur in Alaska. The fossils were found in rock deposited 69 million years ago.

According to Pat Druckenmiller, earth sciences curator at the University of Alaska Museum in Fairbanks, the animal was a variety of hadrosaur, a duck-billed dinosaur that roamed in herds.

The researchers said northern Alaska, in the past, was covered by forest with a much warmer climate. The dinosaur lived in darkness for months and also experienced snow.

The fossils were lumped for at least 25 years with another hadrosaur, Edmontosaurus, a species well-known in Canada and the US, including Montana and South Dakota. The researchers, during a formal study of the Alaska dinosaur, revealed differences in skull and mouth features that made it a different species, Druckenmiller said.

Druckenmiller said the researchers were not immediately able to make out the difference because the Alaska dinosaurs were juveniles. Later, the researchers found some difference in the Alaska fossils, by plotting growth trajectories and by comparing them with juvenile Edmontosourus bones.

The researchers named the creature as Ugrunaaluk kuukpikensis (oo-GROO'-nah-luk KOOK'-pik-en-sis) meaning 'ancient grazer'. The name was chosen by the scientists with assistance from speakers of Inupiaq, the language of Alaska Inupiat Eskimos.

The dinosaurs grew up to 30 feet long, and there hundreds of teeth helped them to chew vegetation. They probably walked on their hind legs but could walk on four-legs, Druckenmiller said.

Museum scientists have excavated and catalogued more than 6,000 bones from the species, more than any other Alaska dinosaur. "It appears that a herd of young animals was killed suddenly, wiping out mostly one similar-aged population to create this deposit", Druckenmiller said.