Fascinating New Discovery At Dinosaur National Monument Features Complete Skull

Dinosaur National Monument officials have announced the discovery of the only complete fossilized skull of an adult sauropod found in the Western Hemisphere. NPS photo, sketch of Abydosaurus mcintoshi found in Dinosaur National Monument, feeding on conifer trees, copyright 2010 by Michael W. Skrepnick.

The fossil fields at Dinosaur National Monument continue to yield their ancient treasures. In a find being hailed for producing the only complete "sauropod skull in the entire Western Hemisphere from the last 80 million years of the Age of Dinosaurs," paleontologists have tapped into a trove of fossilized bones that they hope will produce a complete skeleton of this particular plant-eater.

Collaborating on the find of Abydosaurus mcintoshi (pronounced Ab-id -o-saurus mak-in-toshi) were paleontologists from the monument, Brigham Young University, and the University of Michigan.

The discovery, described this week in the on-line first section of the science journal Naturwissenschaften, came from within the 105-million-year-old Cedar Mountain Formation in the monument that straddles the northeastern Utah-northwestern Colorado border.

“Because skulls are made up of many thin and fragile bones they are easily destroyed and rarely preserved. So although more than 120 species of sauropods have been discovered across the globe, complete skulls are extremely rare," says Dr. Dan Chure, a paleontologist at Dinosaur. “However, skulls are complex structures that provide a great deal of information about the dinosaur’s biology and evolution, so they are extremely important. You can hardly overstate the significance of these fossils.”

According to Brigham Young University researcher Brooks Britt, to date all the Abydosaurus fossils excavated have been of juveniles, "only a mere 25 feet or so in length."

"How large a fully adult individual was is unknown but it was certainly much larger. Although we haven’t found a complete skeleton yet, hope springs eternal in paleontology and we will continue excavations this summer," added Dr. Britt.

University of Michigan researcher Jeff Wilson and his graduate student John Whitlock studied the feeding adaptations of Abydosaurus. Dr. Wilson noted that “(S)auropods, one of the most diverse and long-lived lineages of dinosaurs, are surprising in that they show none of the adaptations seen in other plant-eating dinosaurs, such as beaks for slicing or cheeks to hold in food while chewing."

"Yet in spite of the lack of any specializations," he continued, "they were around for 150 million years and are the largest land-dwelling animals in the history of life.”

According to Mr. Whitlock, “Abydosaurus is from a time period when titanosauriform sauropods began to develop a slimmer tooth shape from the broader teeth of their ancestors. This change in tooth shape is related to changes in diet in a way we are only just beginning to understand, in part because we haven't always had the fossils to tell the whole story. Abydosaurus is the right dinosaur at the right time to answer some of these questions."

This week's announcement is the result of a several years of research, beginning with excavations started in the late 1990s, according to monument officials. The site contains not just one individual but the remains of a group of sauropods, at least four individuals and likely more since additional fossils are still in the ground, they add. Most parts of the skeleton are present: neck and tail vertebrae, shoulder blades, pelvis, arms, legs, hands, feet, and four skulls --- two complete and two incomplete, according to the paleontologists.

The excavation and preparation of this dinosaur’s remains has been a collaborative effort among the National Park Service, volunteers, students, paleontologists, academic institutions, and outside researchers. The fossils are being prepared and stored at the Paleontology Museum at Brigham Young University in Provo, Utah.

What’s in a name?

Scientific names are often a mouthful, but each has a meaning. So what does Abydosaurus mcintoshi mean? The generic name Abydosaurus refers to Abydos, the Greek name for the city along the Nile River (now El Araba el Madfuna) that was the burial place of the head and neck of Osiris, Egyptian god of life, death and fertility—an allusion to the skull and neck of the new dinosaur, which was found in a quarry overlooking the Green River in Dinosaur National Monument; sauros is the Greek word for lizard. The specific name mcintoshi honors the paleontologist Dr. Jack McIntosh, for his many contributions to the study of sauropod dinosaurs and his decades of assistance to Dinosaur National Monument and Brigham Young University.