New Dinosaur Discovery

Natural History Museum names a new genus and species of a dinosaur.

Sphaerotholus goodwini is a new genus and species of pachycephalosaur from the Upper Cretaceous of New Mexico. Pachycephalosaurs (meaning "thick-head lizards") were relatively small, two legged, plant-eating dinosaurs, with thickened skull roofs. Some had heads that were expanded into domes that resemble bowling balls and earned the dinosaurs their nickname "bone heads."

The partial skull is the first pachycephalosaur specimen to be collected from New Mexico and represents one of the most complete pachycephalosaur skulls to be collected from North America. The skull includes the skull roof and most of the braincase.

The new genus Sphaerotholus means "round dome," and the species is named after Mark Goodwin, a paleontologist at the University of California Museum of Paleontology who studies pachycephalosaurs. Dr. Thomas Williamson, Curator of Paleontology at the New Mexico Museum of Natural History and Science, and Thomas Carr, Ph.D. candidate of the University of Toronto, published a description of this new dinosaur in the December 2002 issue of the Journal of Vertebrate Paleontology.

Photograph of the dome of Sphaerotholus on exhibit at the museum.

The holotype, or name-bearer, of the new genus and species is a partial skull that was collected by Paul Sealey, Adjunct Naturalist at the Museum during a collecting trip led by Dr. Williamson in the Spring of 1998. Mr. Sealey collected the skull from the Bisti/De-Na-Zin Wilderness area of northwestern New Mexico, an area managed by the Bureau of Land Management. The specimen is about 73 million years old.

Pachycephalosaurs are extremely rare dinosaurs. Since this discovery, the Museum has collected three additional pachycephalosaur specimens from northwestern New Mexico near Farmington including a partial jaw-only the second pachycephalosaur jaw to be documented from North America.

Two partial pachycephalosaur skulls, including the holotype of the new genus and species, are on display in the Museum's expanded and upgraded "New Mexico's Seacoast" exhibit hall. The exhibit features several new dinosaur specimens-all are from New Mexico and are unique to the state.