U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
Clues to a 50-Year-Old Mystery Unearthed in Groundbreaking Dinosaur Find
Two remarkable new species of horned dinosaurs have been found in Grand Staircase Escalante-National Monument (GSENM). These discoveries offer new clues to a mystery that has left paleontologists deeply puzzled for the last 50 years.
Uncovering a Mystery
In the 1960’s paleontologists began to make a peculiar observation about an area known as Laramidia. This landmass existed during the Late Cretaceous period (about 76 million years ago) when North America was separated by a shallow sea called the Western Interior Seaway. It extended from the Arctic Ocean to the Gulf of Mexico, subdividing the continent in to eastern and western landmasses, known as Appalachia and Laramidia, respectively. Little is known about Appalachia but the rocks of Laramidia exposed in the Western interior of North America hold an abundance of dinosaur remains.
With the available fossils, paleontologists observed that the same major groups of dinosaurs seemed to be present all over Laramidia but it appeared that different species of these groups occurred in the north (including Alberta and Montana) than in the south. It has been difficult to confirm this theory because Utah was located in the southern part of Laramidia where fewer fossils have been found than in the north.
The newest dinosaurs were discovered in GSENM, which encompasses 1.9 million acres of high desert terrain in south-central Utah. This vast and rugged region is part of the National Landscape Conservation System administered by the BLM. In the Late Cretaceous period the GSENM was a subtropical swampy environment about 100 km from the seaway.
These recently discovered plant-eating dinosaurs are close relatives of the famous Triceratops, but they have some defining physical traits that make them unique. Kosmoceratops richardsoni has a total of 15 horns – one over the nose, one atop each eye, one at the tip of each cheek bone, and ten across the rear margin of the bony frill –making it the most ornate headed dinosaur known. The Utahceratops gettyi has a skull 2.3 meters long, a large horn over the nose, and short and blunt eye horns that project strongly to the side rather than upward, much more like the horns of modern bison than those of Triceratops.
These fossils, along with earlier finds at the Grand Staircase–Escalante National Monument (GSENM) confirm that dinosaurs living on Laramidia were divided into at least northern and southern “provinces.”
Seventy-five million years ago there may have been at least two dozen species of rhino-to-elephant sized dinosaurs living on a landmass about one-eighth the size of Africa. Paleontologists are working to understand how these giant dinosaurs were able to co-exist on such a small continent. There is hope that the new fossil discoveries in GSENM will shed some light on the subject.
Note: These findings are the result of an ongoing collaboration between the Bureau of Land Management, the University of Utah, the Utah Geologic Survey, and the Raymond Alf Museum of Paleontology. A recent study of these latest finds was funded in large part by the Bureau of Land Management and the National Science Foundation. The study was led by Scott Sampson and Mark Loewen of the Utah Museum of Natural History (UMNH) and Department of Geology and Geophysics, University of Utah. Additional authors include Andrew Farke (Raymond Alf Museum) Eric Roberts (James Cook University), Eric Lund (University of Utah), Catherine Forster (George Washington University), and Alan Titus (Grand Staircase-Escalante National Monument).