Itsa国际传媒檚 a dinosaur that roamed Albertasa国际传媒檚 badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it sa国际传媒淏ig Sam.sa国际传媒�

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didnsa国际传媒檛 die alone.

sa国际传媒淲e have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,sa国际传媒� Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as sa国际传媒渢he smaller, older cousin of the triceratops.sa国际传媒�

sa国际传媒淭his species of dinosaur is endemic to the Grand Prairie area, so itsa国际传媒檚 found here and nowhere else in the world. They are sa国际传媒� kind of about the size of an Indian elephant and a rhino,sa国际传媒� she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

sa国际传媒淎t the time, sort of in the sa国际传媒�70s and sa国际传媒�80s, paleontology in northern Alberta was virtually unknown,sa国际传媒� said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned sa国际传媒渋tsa国际传媒檚 actually one of the densest dinosaur bonebeds in North America.sa国际传媒�

sa国际传媒淚t contains about 100 to 300 bones per square metre,sa国际传媒� she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

sa国际传媒淭heir distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,sa国际传媒� she said.

sa国际传媒淚t makes them look a little strange. Itsa国际传媒檚 the one dinosaur that if you find it, itsa国际传媒檚 the only possible thing it can be.sa国际传媒�

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, sa国际传媒渁s if the animal was lying on its back,sa国际传媒� but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out sa国际传媒� very carefully sa国际传媒� with a crane, and was to be shipped on a trolley to the museum for study.

sa国际传媒淚 have extracted skulls in the past. This is probably the biggest one Isa国际传媒檝e ever done though,sa国际传媒� said Bamforth.

sa国际传媒淚tsa国际传媒檚 pretty exciting.sa国际传媒�