March 22, 2009
University of Alaska Museum of the North earth sciences curator Patrick Druckenmiller and University of Oslo paleontologist Jørn Hurum were members of the research team that discovered the fossil on the last day of their August 2007 field season. They returned in June 2008 to excavate the specimen.
After several months of cleaning and analyzing the specimen, the researchers team has determined that the pliosaur, dubbed "Predator X," was at least 50 feet long and weighed 45 tons. Its anatomy and overall structure suggest that it was the top marine predator in its day.
Among the various parts of the skull discovered, the pliosaur's occiptial condyle, which connects the base of the skull to the vertebral column, was key to the analysis. The bone is present in all mammals and reptiles, and was used as one type of yardstick by which size comparisons could be made between different species. In this pliosaur, the condyle measures six inches in diameter; by comparison, the condyle of Tyranosaurus rex measures just three inches.
Druckenmiller used a CT scan of another pliosaur skull to analyze the brain shape for clues about pliosaur locomotion and development of the senses. Findings from that CT scan were compared to the new specimen to determine that the brain was broadly similar in shape and proportional in size to the brain of a great white shark, one of today s top marine predators.
Researchers from West Chester University (Pennsylvania), Duke University (North Carolina) and Vassar College (New York) studied the flippers and their hydrodynamics to calculate the speed at which the pliosaur could swim and to determine how fast it could accelerate in the water.
A team of University of Oslo students and volunteers continues work to stabilize and assemble more than 20,000 fragments of the skeleton retrieved from the field.
A pliosaur is a type of plesiosaur, a group of extinct reptiles that lived in the world's oceans 205-65 million years ago. Pliosaurs are characterized by tear-drop shaped bodies with two pairs of powerful flippers used to propel them through the water. They were top predators during their day, preying upon fish, squid-like animals and other marine reptiles. They averaged 16-20 feet in length with flippers 3-4 feet long.
Atlantic Productions documented the excavation of the specimen in Svalbard as well as the subsequent analysis of the specimen. Their two-hour documentary "Predator X" will air on the History Channel on Sunday, March 29.
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