Paleontologists from Dallas uncover juvenile specimen

Dallas Examiner | 6/30/2013, 1:16 a.m.
Paleontologists from the Perot Museum of Science and Nature in Dallas have uncovered a juvenile specimen in the same ground ...
Twenty months after announcing their discovery of a new species found in Alaska called the Pachyrhinosaurus perotorum, paleontologists from the Perot Museum of Nature and Science in Dallas have since uncovered a juvenile specimen that came from the same hole in the ground. The scientific paper describing the find – entitled “An immature Pachyrhinosaurus perotorum(Dinosauria: Ceratopsidae) nasal reveals unexpected complexity of craniofacial ontogeny and integument in Pachyrhinosaurus” – was posted late yesterday on the prestigious science journal. Shown here is a series of Pachyrhinosaurus perotorum skulls (on left) and stylized life reconstructions (on right) at three (of a proposed six) different life stages. Perot Museum of Nature and Science

Special to The Dallas Examiner

Paleontologists from the Perot Museum of Science and Nature in Dallas have uncovered a juvenile specimen in the same ground 20 months after announcing the discovery of a new Alaskan species called the Pachyrhinosaurus perotorum.

The scientific paper describing the find was posted last week on the prestigious science journal PLOS ONE, an international, peer reviewed, open access online publication featuring reports on primary research from all scientific disciplines. Dallas paleontologist Anthony R. Fiorillo, Ph.D., the museum’s curator of earth sciences, and Ronald S. Tykoski, Ph.D, fossil preparer at the museum, co-authored the report.

Fiorillo discovered the adult version of the Pachyrhinosaurus perotorum during a return excavation in 2006 to the North Slope of Alaska, many miles north of the Arctic Circle. The species was formally named in October 2011 in recognition of the Perot family for their long history and support for science and science education.

“In our early years of work, we initially thought we had only one age profile of the adult. But as the preparation work has continued in recent years on the additional blocks from that same Alaskan expedition site, it was a true ‘aha’ moment to find the younger skull as well,” Fiorillo said.

The discovery of the juvenile came in 2012 when Tykoski was working on a smallish block about the size of a football focusing on a strip bone about an inch wide exposed at the surface. One of the key features of the species is the top of the nose. The juvenile specimen has a small, narrow horn on the snout that after puberty grows and thickens into a lumpy battering-ram-like bulge, a mark that distinguishes the Pachyrhinosaurus perotorum.

“After ruling out all of the possibilities through the process of elimination, we realized this was a juvenile specimen,” Tykoski said.

The discovery of both the adult and juvenile specimens has further ignited the paleontologists’ passion to keep plugging away at the thousands of pounds remaining in the jackets, which are stored in collection spaces at the Perot Museum’s Fair Park campus.

A display featuring the adult Pachyrhinosaurus perotorum is currently installed in the T. Boone Pickens Life Then and Now Hall, a 14,000 square foot hall in the museum.