Montana bone find leads to new dinosaur

PHILADELPHIA — A curious piece of bone spotted by a University of Pennsylvania professor during a horseback ride in southern Montana led to the discovery of a new dinosaur with a long neck, a whip-like tail and a mysterious extra hole in its skull.

The new find — a Suuwassea emilieae — is a sauropod, a classification of plant-eating dinosaurs with long necks and tails, small heads, and four elephant-like legs. At 50 feet long, it's a smaller cousin of better-known sauropods Diplodocus and Apatosaurus.

The 150-million-year-old creature is described by Penn scientists in the current issue of the paleontology journal Acta Paleontologica Polonica.

"It has a number of distinguishing features, but the most striking is this second hole in its skull, a feature we have never seen before in a North American dinosaur," said Peter Dodson, senior author of the research study and anatomy professor at Penn's veterinary school.

The Jurassic-age find was first spotted by William Donawick, emeritus professor of surgery at Penn's School of Veterinary Medicine, while on a horseback ride in fall 1998 in far southern Montana, not far from his daughter and son-in-law's Wyoming ranch. He returned to Philadelphia with a piece of bone for his colleague Dodson, who found it tantalizing enough that an expedition got under way the following summer.

Researchers have named the dinosaur Suuwassea emilieae (SOO-oo-WAH-see-uh eh-MEE-LEE-aye), after a Crow Indian word meaning "ancient thunder" and for the late Philadelphia socialite Emilie deHellebrath, who funded the digs that unearthed more than 50 bones, from a 43-inch shoulder blade and a 53-inch rib to the two-holed skull that has scientists stumped.

"The extra hole in the skull is still a mystery," said Jerry Harris, study co-author and Penn graduate student researcher. "It has only been seen before in two dinosaurs from Africa and one from South America." While its Diplodocus relatives have a single hole on the top of the skull for the nasal cavity, Suuwassea second hole's purpose is unknown, he said.

The bones were unearthed in 1999 and 2000 but had to be coaxed from their rocky enclosures, cleaned up, and subjected to a lengthy process of measurements, comparative studies, published papers and peer review before passing muster as a new dinosaur, Dodson said.

Suuwassea emilieae's new home is the Academy of Natural Sciences in Philadelphia, where it will be available for teachers, researchers and students to study. It may even be assembled and displayed one day, said academy paleontologist Ted Daeschler.