Amazing Horned Dinosaurs Unearthed on 'Lost Continent'; New Discoveries Include Bizarre Beast With 15 Horns
ScienceDaily (Sep. 22, 2010) — Two remarkable new species of horned dinosaurs have been found in Grand Staircase-Escalante National Monument, southern Utah. The giant plant-eaters were inhabitants of the "lost continent" of Laramidia, formed when a shallow sea flooded the central region of North America, isolating the eastern and western portions of the continent for millions of years during the Late Cretaceous Period.
Artist's rendering of two new species of dinosaur -- Utahceratops gettyi and Kosmoceratops richardsoni -- discovered in the Grand Staircase-Escalante National Monument of southern Utah. (Credit: Courtesy of Utah Museum of Natural History)
The study, funded in large part by the Bureau of Land Management and the National Science Foundation, 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), Joshua Smith (University of Utah), Catherine Forster (George Washington University), and Alan Titus (Grand Staircase-Escalante National Monument).
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New Horned Dinosaurs from Utah Provide Evidence for Intracontinental Dinosaur Endemism
Scott D. Sampson1*, Mark A. Loewen1, Andrew A. Farke2,Eric M. Roberts3, Catherine A. Forster4, Joshua A. Smith1,Alan L. Titus5
1 Utah Museum of Natural History and Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, United States of America, 2 Raymond M. Alf Museum of Paleontology, Claremont, California, United States of America, 3 School of Earth and Environmental Science, James Cook University, Townsville, Queensland, Australia, 4 Department of Biological Sciences, George Washington University, Washington, D. C. United States of America, 5 Grand Staircase-Escalante National Monument, Bureau of Land Management, Kanab, Utah, United States of America
Abstract
During much of the Late Cretaceous, a shallow, epeiric sea divided North America into eastern and western landmasses. The western landmass, known as Laramidia, although diminutive in size, witnessed a major evolutionary radiation of dinosaurs. Other than hadrosaurs (duck-billed dinosaurs), the most common dinosaurs were ceratopsids (large-bodied horned dinosaurs), currently known only from Laramidia and Asia. Remarkably, previous studies have postulated the occurrence of latitudinally arrayed dinosaur “provinces,” or “biomes,” on Laramidia. Yet this hypothesis has been challenged on multiple fronts and has remained poorly tested.
Methodology/Principal Findings
Here we describe two new, co-occurring ceratopsids from the Upper Cretaceous Kaiparowits Formation of Utah that provide the strongest support to date for the dinosaur provincialism hypothesis. Both pertain to the clade of ceratopsids known as Chasmosaurinae, dramatically increasing representation of this group from the southern portion of the Western Interior Basin of North America. Utahceratops gettyi gen. et sp. nov.—characterized by short, rounded, laterally projecting supraorbital horncores and an elongate frill with a deep median embayment—is recovered as the sister taxon to Pentaceratops sternbergii from the late Campanian of New Mexico.Kosmoceratops richardsoni gen. et sp. nov.—characterized by elongate, laterally projecting supraorbital horncores and a short, broad frill adorned with ten well developed hooks—has the most ornate skull of any known dinosaur and is closely allied to Chasmosaurus irvinensis from the late Campanian of Alberta.
Conclusions/Significance
Considered in unison, the phylogenetic, stratigraphic, and biogeographic evidence documents distinct, co-occurring chasmosaurine taxa north and south on the diminutive landmass of Laramidia. The famous Triceratops and all other, more nested chasmosaurines are postulated as descendants of forms previously restricted to the southern portion of Laramidia. Results further suggest the presence of latitudinally arrayed evolutionary centers of endemism within chasmosaurine ceratopsids during the late Campanian, the first documented occurrence of intracontinental endemism within dinosaurs.
Citation: Sampson SD, Loewen MA, Farke AA, Roberts EM, Forster CA, et al. (2010) New Horned Dinosaurs from Utah Provide Evidence for Intracontinental Dinosaur Endemism. PLoS ONE 5(9): e12292.
doi:10.1371/journal.pone.0012292
Editor: Anna Stepanova, Paleontological Institute, Russian Federation
Received: May 18, 2010; Accepted: July 20, 2010; Published: September 22, 2010
Copyright: © 2010 Sampson et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by grants from the National Science Foundation (EAR 0745454, 0819953; http://www.nsf.gov/funding/), Bureau of Land Management (GSENM; http://www.blm.gov), Discovery Quest (http://www.discovery.com), and the University of Utah (http://www.utah.edu). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: ssampson@umnh.utah.edu
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