Paleontologist announces discovery 
of new horned dinosaur species on BLM lands in Alaska

Pachyrhinosaurus perotorum. Illustration by Karen Carr

Weighing in at about four tons, standing seven feet high on four legs and about 18 feet long, it’s roughly the size of a rhino, eats plants, and is from the Late Cretaceous, around 70 million years ago. Paleontologist Anthony R. Fiorillo, Ph.D., and his team discovered this new species of ceratopsid (horned) dinosaur Pachyrhinosaurus near the Colville River on BLM-managed lands in Alaska. Fiorillo, from the Museum of Nature & Science in Dallas, Tex., announced the discovery of Pachyrhinosaurus perotorum at the Society of Vertebrate Paleontology 71st Annual Meeting Nov. 2-5 in Las Vegas, Nev.

The dinosaur discovery actually happened over the summer of 2006. While performing exploration work near the Colville River on land within the National Petroleum Reserve-Alaska, Dr. Fiorillo’s team excavated a large deposit of hundreds of bones, including some partial skulls, from at least 10 individual Pachyrhinosaurus dinosaurs. The find was unprecedented.

“Discovering hundreds of bones from all these pachyrhinosaurs in one spot was unbelievably exciting, and we really thought the expedition was an incredible success. To later realize that we had unearthed a whole new species was one of the best days of my career,” said Dr. Fiorillo.

Because of the jumbled and fragmentary nature of the materials recovered in 2006, it took over four years of painstaking study of the remains in Dallas to reveal that the dinosaurs were a new species of Pachyrhinosaurus. In early 2011, Dr. Fiorillo and his colleague Dr. Ronald S. Tykoski were stunned and excited when newly cleaned and reassembled pieces clearly showed that they had found a new species of Pachyrhinosaurus. The species is based on a partial skull and two fragments of parietals, which in Ceratopsians are the bones that formed the frill, a boney structure extending from the back of the skull over the dinosaur’s neck. The remains showed significant morphological differences from any prior Pachyrhinosaurus remains found elsewhere in the world, including from parts of northern Canada.

What makes the new species special is that it was a polar dinosaur, living on a landscape dominated by coniferous trees. These dinosaurs lived in herds demonstrating that the ancient Arctic was a rich biological ecosystem. When P. perotorum lived around 70 million years ago, the part of Alaska where it was found was warmer than today. It was also a time when Alaska was situated at latitudes similar to or even higher than its current geographical position, meaning that its northern inhabitants experienced extended periods of winter darkness. How such dinosaurs lived in those conditions is a key question still studied today.

A full life-size reconstruction of the new dinosaur will be featured in the Dallas Museum, recently renamed the Perot Museum of Nature & Science due to the strong support of the family of Ross and Margot Perot, for whom the new dinosaur is named.

For additional information, go to http://natureandscience.org/information/pdf/press_room/102811_pachyrhinosaurus.pdf