Dr. Kenneth Lacovara, Drexel University

Scientists have discovered and described a new supermassive dinosaur species with the most complete skeleton ever found of its type. At 85 feet (26 m) long and weighing about 65 tons (59,300 kg) in life, Dreadnoughtus schrani is the largest land animal for which a body mass can be accurately calculated. Its skeleton is exceptionally complete, with over 70 percent of the bones, excluding the head, represented. Because all previously discovered super-massive dinosaurs are known only from relatively fragmentary remains, Dreadnoughtus offers an unprecedented window into the anatomy and biomechanics of the largest animals to ever walk the Earth.

"Dreadnoughtus schrani was astoundingly huge," said Kenneth Lacovara, PhD, an associate professor in Drexel University's College of Arts and Sciences, who discovered the Dreadnoughtus fossil skeleton in southern Patagonia in Argentina and led the excavation and analysis. "It weighed as much as a dozen African elephants or more than seven T. rex. Shockingly, skeletal evidence shows that when this 65-ton specimen died, it was not yet full grown. It is by far the best example we have of any of the most giant creatures to ever walk the planet."

Lacovara and colleagues published the detailed description of their discovery, defining the genus and species Dreadnoughtus schrani, in the journal Scientific Reports from the Nature Publishing Group today. The new dinosaur belongs to a group of large plant eaters known as titanosaurs. The fossil was unearthed over four field seasons from 2005 through 2009 by Lacovara and a team including Lucio M. Ibiricu, PhD, of the Centro Nacional Patagonico in Chubut, Argentina, the Carnegie Museum of Natural History’s Matthew Lamanna, PhD, and Jason Poole of the Academy of Natural Sciences of Drexel University, as well as many current and former Drexel students and other collaborators.

Over 100 elements of the Dreadnoughtus skeleton are represented from the type specimen, including most of the vertebrae from the 30-foot-long tail, a neck vertebra with a diameter of over a yard, scapula, numerous ribs, toes, a claw, a small section of jaw and a single tooth, and, most notably for calculating the animal's mass, nearly all the bones from both forelimbs and hindlimbs including a femur over 6 feet tall and a humerus. A smaller individual with a less-complete skeleton was also unearthed at the site.

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