At the Top of the Grand Staircase
The Late Cretaceous of Southern Utah
Publication Year: 2013
The Grand Staircase-Escalante National Monument in Utah is the location of one of the best-known terrestrial records for the late Cretaceous. A major effort in the new century has documented over 2,000 new vertebrate fossil sites, provided new radiometric dates, and identified five new genera of ceratopsids, two new species of hadrosaur, a probable new genus of hypsilophodontid, new pachycephalosaurs and ankylosaurs, several kinds of theropods (including a new genus of oviraptor and a new tyrannosaur), plus the most complete specimen of a Late Cretaceous therizinosaur ever collected from North America, and much more. At the Top of the Grand Staircase: The Late Cretaceous of Southern Utah documents this major stepping stone toward a synthesis of the ecology and evolution of the Late Cretaceous ecosystems of western North America.
Published by: Indiana University Press
Series: Life of the Past
Title Page, Copyright Page
In 1982, Tom Ryer came to the University of Wyoming to give a talk on coal geology in the Cretaceous of Utah. A few years earlier (1979), Jason Lillegraven had completed his groundbreaking Mesozoic Mammals book, and the gaps in our record of Cretaceous mammals were fresh in my mind. I asked Tom what was landward of these Cretaceous ...
During May 22–23, 2009, dozens of researchers gathered in St. George, Utah, at a conference titled “Learning from the Land: Advances in Western Interior Late Cretaceous Geology and Paleontology.” I organized this conference under the sponsorship of Grand Staircase–Escalante National Monument, the Utah Museum of Natural History...
List of Contributors
1 One Hundred Thirty Years of Cretaceous Research in Southern Utah
Southern Utah possesses a wild, stark, rugged landscape that leaves most people who experience it irrevocably and profoundly changed. Scenic wonders such as the Grand Canyon, Bryce Canyon (Fig. 1.1), Zion Canyon, The Wave, Buckskin Gulch, Cedar Breaks, and Capitol Reef are deservedly ...
2 Geologic Overview
Cretaceous strata in southern Utah were deposited in the proximal portion of the Sevier Foreland Basin. Total thickness of Cretaceous sediments probably exceeded 3000 m in the region before mid-Laramide uplift and erosion. Exposures are primarily found at the Kaiparowits Plateau...
3 Accumulation of Organic Carbon–Rich Strata along the Western Margin and in the Center of the North American Western Interior Seaway during the Cenomanian–Turonian Transgression
During the Cretaceous Period, the North American Western Interior Seaway occupied a rapidly subsiding north–south-trending basin that was characterized by substantial clastic sediment input derived from uplifted volcanic terranes of the Sevier orogenic belt to the west. At times of maximum transgression, the shoreline of the Western...
4 Tectonic and Sedimentary Controls, Age, and Correlation of the Upper Cretaceous Wahweap Formation, Southern Utah
The Wahweap Formation was deposited by fluvial to estuarine systems in the central part of the Western Interior Basin, between the Sevier fold-and-thrust belt to the west and the Western Interior Seaway to the east, during the Late Cretaceous. Today, the Wahweap Formation is exposed on the Markagunt, Paunsaugunt, and Kaiparowits...
5 Implications of the Internal Plumbing of a Late Cretaceous Sand Volcano: Grand Staircase–Escalante National Monument, Utah
A vertical, cross-sectional exposure through a well-preserved sand blow and the associated volcano was discovered 1.8 m above the base of the Upper Cretaceous upper member of the Wahweap Formation. Preserved features within the feeder conduit (pipe) of the sand volcano facilitate reconstruction of the vertical fl uid fl ow and interpretation...
6 The Kaiparowits Formation: A Remarkable Record of Late Cretaceous Terrestrial Environments, Ecosystems, and Evolution in Western North America
Updated sedimentological and paleontological data support earlier assertions that the Kaiparowits Formation was deposited in a wet alluvial to coastal plain setting with an abundance of large river channels and perennial ponds, lakes, and wetlands. A synthesis of available geochronological data from contemporaneous Upper Cretaceous ...
7 A Late Campanian Flora from the Kaiparowits Formation, Southern Utah, and a Brief Overview of the Widely Sampled but Little-Known Campanian Vegetation of the Western Interior of North America
Fossil-bearing terrestrial strata of Campanian age are widespread in the Western Interior Basin of North America and contain some of the world’s best known and most diverse dinosaurian faunas. More than 30 Campanian megafl oras have been found from Texas to the Arctic, but our understanding of the vegetation they represent is poor ...
8 Continental Invertebrates and Trace Fossils from the Campanian Kaiparowits Formation, Utah
A survey of over 50 localities for invertebrate fossils and their traces in the mudstones and sandstones of the Kaiparowits Formation, which spans 1.8 million years of Late Cretaceous (Campanian) time, demonstrates that it is one of the most prolific units in the Western Interior. Pulmonates,...
9 Elasmobranchs from Upper Cretaceous Freshwater Facies in Southern Utah
Elasmobranch teeth from freshwater facies are common in many microvertebrate assemblages in the Upper Cretaceous of western North America. Research on the essentially complete Upper Cretaceous terrestrial microvertebrate record of southern Utah has resulted in the collection of specimens from many stratigraphic horizons not sampled ...
10 Freshwater Osteichthyes from the Cenomanian to Late Campanian of Grand Staircase–Escalante National Monument, Utah
Fossil assemblages from the Grand Staircase region of Utah provide data on patterns of diversity of bony fi sh from the Cenomanian through the late Campanian from the southern parts of the Western Interior of North America. Basal actinopterygians are prominent members of the assemblages and generally can be identifi ed to at least family ...
11 Preliminary Report on Salamanders (Lissamphibia; Caudata) from the Late Cretaceous (Late Cenomanian–Late Campanian) of Southern Utah, U.S.A.
Here we report on salamander fossils (vertebrae and jaws) and taxa identifi ed from 19 microvertebrate localities of late Cenomanian–late Campanian age (an interval of about 25 million years) from the Dakota, Straight Cliffs, Iron Springs, Wahweap, and Kaiparowits formations in southwestern Utah, U.S.A. All three salamander families known from...
12 Anuran Ilia from the Upper Cretaceous of Utah – Diversity and Stratigraphic Patterns
Thanks to their relatively robust build and distinctive structure, isolated ilia are among the most commonly recovered anuran bones from fossil micovertebrate sites. Across the spectrum of known anurans, there is considerable variation in features of the ilium. With some caveats, these features may be useful for assigning anuran ilia to biological ...
13 Turtles from the Kaiparowits Formation, Utah
Fossil turtle remains are abundant in the Kaiparowits Formation and add to our understanding of turtle diversity, taxonomic relationships, and biogeography during the Late Cretaceous. A minimum of 14 taxa are present. Latitudinal patterns are identifi ed by comparing the Kaiparowits ...
14 Review of Late Cretaceous Mammalian Faunas of the Kaiparowits and Paunsaugunt Plateaus, Southwestern Utah
Mammals have been recovered by wet screen washing of microvertebrate localities in the Dakota Formation (Cenomanian); the Smoky Hollow (Turonian) and John Henry (Coniacian–Santonian) members of the Straight Cliffs Formation; the Wahweap Formation (lower–middle Campanian); and the Kaiparowits Formation (upper Campanian). ...
15 Late Cretaceous Mammals from Bryce Canyon National Park and Vicinity, Paunsaugunt Plateau, Southwestern Utah
The mammalian fauna from the John Henry Member of the Straight Cliffs Formation (Santonian) of the Paunsaugunt Plateau described here includes an unidentifi ed triconodont, cf. Alticonodon, Mesodma sp. cf. M. minor, Mesodma sp., ?Mesodma sp., Cimolodon sp. cf. C. foxi, Cimolodon similis, Cimolodon sp. cf. C. similis, ?Cimolodon ...
16 Lizards and Snakes from the Cenomanian through Campanian of Southern Utah: Filling the Gap in the Fossil Record of Squamata from the Late Cretaceous of the Western Interior of North America
A rich and diverse fauna of lizards and snakes has been recovered from the Cenomanian–Campanian of southern Utah. The specimens reported herein represent eight new taxa, 19 named taxa, and 34 distinct, unnamed morphotypes from the Dakota Formation (Cenomanian), Smoky Hollow Member of the Straight Cliffs Formation...
17 Crocodyliforms from the Late Cretaceous of Grand Staircase–Escalante National Monument and Vicinity, Southern Utah, U.S.A.
Although the Kaiparowits Basin of southern Utah contains an excellent Late Cretaceous stratigraphic record of nonmarine fossiliferous sediments, crocodyliforms from these deposits remain poorly known. Isolated teeth and osteoderms from the Dakota and Straight Cliffs formations document the presence of widespread large clades such as...
18 Review of Late Cretaceous Ankylosaurian Dinosaurs from the Grand Staircase Region, Southern Utah
New ankylosaur specimens from Grand Staircase– Escalante National Monument, Utah, provide data on the distribution and diversity of ankylosaurian dinosaurs of southern Laramidia. These materials are from the Dakota, Straight Cliffs, Wahweap, Kaiparowits, and laterally equivalent formations of the Grand Staircase of southern Utah....
19 Ornithopod Dinosaurs from the Grand Staircase–Escalante National Monument Region, Utah, and Their Role in Paleobiogeographic and Macroevolutionary Studies
Ornithopod dinosaurs were bipedal, herbivorous dinosaurs represented in the Late Cretaceous of North America by basal ornithopods (“hypsilophodontids”) and a clade of derived iguanodontians containing, in part, hadrosaurids. Recent research focused on the Cretaceous macrovertebrates of Grand Staircase–Escalante National Monument and surrounding...
20 Review of Pachycephalosaurian Dinosaurs from Grand Staircase–Escalante National Monument, Southern Utah
Recent fieldwork in the Upper Cretaceous (Campanian) Wahweap and Kaiparowits formations of southern Utah have resulted in the recovery of the fi rst cranial remains of pachycephalosaurian dinosaurs from these units. Pachycephalosaurs from the Wahweap Formation are represented ...
21 Ceratopsid Dinosaurs from the Grand Staircase of Southern Utah
Recent fieldwork and research in the Upper Cretaceous Wahweap and Kaiparowits formations of southern Utah has greatly increased our knowledge and understanding of ceratopsid dinosaurs from the Campanian of southern Laramidia. This research, undertaken by the Kaiparowits Basin and Horned Dinosaur projects, has documented...
22 Late Cretaceous Theropod Dinosaurs of Southern Utah
Recent interest in Upper Cretaceous formations of southern Utah including intense collection efforts by the Kaiparowits Basin Project – a joint collaboration between the Utah Museum of Natural History, the University of Utah, and the Bureau of Land Management – has added considerably to our understanding of dinosaur diversity in the Western ...
23 A Trackmaker for Saurexallopus: Ichnological Evidence for Oviraptorosaurian Tracks from the Upper Cretaceous of Western North America
Identifying the trackmaker of Saurexallopus has been an intriguing dilemma since footprints of this kind were fi rst described in 1997. The large bird-like tracks of Saurexallopus are known from the Upper Cretaceous of North America. At this time, the only body fossils of animals with tetradactyl bird-like feet large enough to produce these...
24 First Report of Probable Therizinosaur (cf. Macropodosaurus) Tracks from North America, with Notes on the Neglected Vertebrate Ichnofauna of the Ferron Sandstone (Late Cretaceous) of Central Utah
Although known for some years, vertebrate tracks from the Ferron Sandstone in the San Rafael Swell (Emery County, Utah) have never been described in detail. A new find attributed to cf. Macropodosaurus, one of the least known dinosaur tracks, is the first report of the ichnogenus from North America. Macropodosaurus is otherwise known...
25 Fossil Vertebrates from the Tropic Shale (Upper Cretaceous), Southern Utah
The upper Cenomanian–upper Turonian Tropic Shale of southern Utah contains an abundant and diverse vertebrate fauna. A decade of collecting, mostly by crews from the Museum of Northern Arizona, has secured specimens representing a dinosaur, at least five different shortnecked plesiosaur genera, two genera of turtles, and a normal ...
26 Paleontological Overview and Taphonomy of the Middle Campanian Wahweap Formation in Grand Staircase–Escalante National Monument
The Wahweap Formation preserves the most diverse middle Campanian terrestrial fauna in North America, based largely on information gained by the study of microvertebrate fossils collected by wet screen washing. These studies have documented a minimum of five freshwater...
27 Taphonomy of a Subadult Teratophoneus curriei (Tyrannosauridae) from the Upper Campanian Kaiparowits Formation of Utah
The Upper Campanian Kaiparowits Formation of Utah has recently produced an associated subadult skeleton of the tyrannosaurid dinosaur Teratophoneus curriei. The approximately 65% complete skeleton includes most of the skull; representative elements from the entire axial column; a complete pelvis; and the right femur, tibia, and...
28 A New Macrovertebrate Assemblage from the Late Cretaceous (Campanian) of Southern Utah
For most of the Late Cretaceous, a shallow epeiric sea subdivided North America into eastern and western landmasses – Appalachia and Laramidia, respectively. Whereas little is known of Appalachian faunas, Laramidia has yielded an abundant terrestrial fossil record, arguably the best continent-scale example for any Mesozoic time interval. ...