James Kirkland

Systematic prospecting in the Oliete Geological Sub-basin (Aragonese Branch of the Iberian Range), specifically at an open-pit mine in the Escucha Formation (Lower Cretaceous) in Ariño (Teruel, Spain), has revealed a fossiliferous layer with abundant vertebrate and other early Albian fossils. The fossiliferous stratigraphic level coincides with the floor of the mining operations, i.e. the bonebed is just below the lowest layer of coal mined for industrial purposes. Coal mining in this area of Teruel province has occurred for over a century and intense mining activity is at the present time a major economic force in the region. The new discoveries at this Mesozoic vertebrate locality presented in this paper document the most important Albian dinosaur site identified in Europe. This important discovery is a direct result of mining activity, without which these important data would have remained buried hundreds of metres underground. These discoveries below the coal seams at Ariño fill out the Lower Cretaceous terrestrial record of Europe and expand upon the palaeogeographic context by which Europe may be compared against correlative dinosaur faunas in North America, Asia and North Africa.

"The Lower Cretaceous section exposed in northeastern Utah includes the Cedar Mountain and Dakota Formations. The Cedar Mountain Formation consists of fluvial-lacustrine and pedogenic carbonate beds and includes important dinosaur sites. Its age in northeastern Utah is early to late Albian from a radiometric age (detrital U-Pb zircons) of 104.46 ± 0.95 Ma associated with a well-preserved sauropod skull, che¬mostratigraphic analysis, and palynology in the overlying Dakota Formation. Part of the Cedar Mountain Formation was deposited during the Kiowa–Skull Creek depositional cycle.
The Dakota Formation consists of fluvial sandstone and mudstone beds; however, locally it includes a thin interval of marine mudstone and shale beds. Dinoflagellate cysts re¬covered from this basal marine interval represent peak sea level during the Kiowa–Skull Creek depositional cycle and the first marine incursion of the Cretaceous Western Interior Seaway into Utah. The age for this event is middle late Al¬bian. Only nonmarine palynomorphs were recovered from beds above the marine interval. An ash bed in the middle Dakota yielded a U-Pb zircon age of 101.4 ± 0.4 Ma, which correlates to the newly defined Muddy-Mowry depositional cycle.
The Mowry Shale consists of siliceous marine shale that represents widespread open-marine conditions for the area. The radiometric age of the Mowry is between 98.5 ± 0.5 Ma and 97.2 ± 0.7 Ma (40Ar/39Ar sanidine) from bentonite beds in Wyoming. However, the biostratigraphic age is contro¬versial because of downward revision to key neogastroplitid ammonite zones, revision of the Albian-Cenomanian bound¬ary age to 99.6 Ma, and recently published palynostrati¬graphic work.
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"Background:
The Yellow Cat Member of the Cedar Mountain Formation (Early Cretaceous, Barremian? – Aptian) of Utah has yielded a rich theropod fauna, including the coelurosaur Nedcolbertia justinhofmanni, the therizinosauroid Falcarius utahensis, the troodontid Geminiraptor suarezarum, and the dromaeosaurid Utahraptor ostrommaysorum.  Recent excavation has uncovered three new dromaeosaurid specimens.  One specimen, which we designate the holotype of the new genus and species Yurgovuchia doellingi, is represented by a partial axial skeleton and a partial left pubis.  A second specimen consists of a right pubis and a possibly-associated radius.  The third specimen consists of a tail skeleton that is unique among known Cedar Mountain dromaeosaurids.

Methodology/Principal Findings:
Y. doellingi resembles Utahraptor ostrommaysorum in that its caudal prezygapophyses are elongated but not to the degree present in most dromaeosaurids.  The specimen represented by the right pubis exhibits a pronounced pubic tubercle, which is a velociraptorine trait that is absent in Y. doellingi.  The specimen represented by the tail skeleton exhibits the extreme elongation of the caudal prezygapophyses that is typical of most dromaeosaurids.  Here we perform a phylogenetic analysis to determine the phylogenetic position of Y. doellingi.  Using the resulting phylogeny as a framework, we trace changes in character states of the tail across Coelurosauria to elucidate the evolution of the dromaeosaurid tail.

Conclusions/Significance:
The new specimens add to the known diversity of Dromaeosauridae and to known diversity within the Yellow Cat paleofauna.  Their presence demonstrates that the lower Yellow Cat paleofauna included at least three small, predatory theropods (including two dromaeosaurid species), and the upper Yellow Cat paleofauna included at least two dromaeosaurid species. Phylogenetic analysis places Y. doellingi in a clade with Utahraptor, Achillobator, and Dromaeosaurus.  Character state distribution indicates that the presence of intermediate-length caudal prezygapophyses in that clade is not an evolutionarily precursor to extreme prezygapophyseal elongation but represents a secondary shortening of caudal prezygapophyses.  It appears to represent part of a trend within Dromaeosauridae that couples an increase in tail flexibility with increasing size.
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" U-Pb ages of detrital zircon (DZ) grains from Lower Cretaceous foreland basin quartzite conglomerate clasts and sandstones—and from potential sources of quartzite clasts and sandstones—record unroofing of the Sevier fold-thrust belt of Utah and the Mogollon Highlands of Arizona.  The oldest Cretaceous deposits in Utah, the Buckhorn Conglomerate (Berremian-Aptian) of the Cedar Mountain Formation, contain sandstone and quartzite clasts with DZ age spectra statistically indistinguishable to Mississippian-Jurassic sandstones on the Colorado Plateau and in Sevier thrust sheets.  Medial Albian Cedar Mountain Formation conglomerates on the western San Rafael Swell (Short Canyon Conglomerate) and basal Cedar Mountain conglomerates on the Wasatch Plateau in central Utah and the Markagunt Plateau in southwest Utah contain quartzite clasts derived from the Ordovician-Devonian interval in the thrust belt. Middle Albian-lower Cenomanian San Pitch and Sanpete Formations of the lower Indianola Group and upper Dakota Sandstone in central Utah were supplied with Cambrian-Precambrian quartzite clasts, thus recording full incision into approximately 16,000 m of allochthonous strata in the central Utah thrust belt by mid Albian.  These three geochronological provenance intervals define three inverted chronofacies in Lower Cretaceous and basal Upper Cretaceous synorogenic deposits, thus recording a complete unroofing sequence of allochthonous strata in the central Utah thrust belt. 
The Buckhorn Conglomerate on the San Rafael Swell and the Poison Strip Sandstone in eastern Utah do not share a common provenance.  The Poison Strip contains significant proportions of Cordilleran arc derived grains that are also commonly found in the lower Burro Canyon Formation to the southeast, whereas in the Buckhorn Conglomerate they are rare.  Whether this phenomenon is due to temporal or sediment dispersal differences are unclear, it may signal the onset of longitudinal trunk river development subsequent to Buckhorn deposition and coeval with orogenesis.  An additional source of Mesozoic volcanic arc DZ grains might include recycling from tephras within Mesozoic strata from local and southern sources in the Mogollon Highlands. 
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"Abstract
Background: Basal iguanodontian dinosaurs were extremely successful animals, found in great abundance and diversity almost worldwide during the Early Cretaceous. In contrast to Europe and Asia, the North American record of Early Cretaceous basal iguanodonts has until recently been limited largely to skulls and skeletons of Tenontosaurus tilletti.
Methodology/Principal Findings: Herein we describe two new basal iguanodonts from the Yellow Cat Member of the Cedar Mountain Formation of eastern Utah, each known from a partial skull and skeleton. Iguanacolossus fortis gen. et sp. nov. and Hippodraco scutodens gen. et sp. nov. are each diagnosed by a single autapomorphy and a unique combination of characters. 
Conclusions/Significance: Iguanacolossus and Hippodraco add greatly to our knowledge of North American basal iguanodonts and prompt a new comprehensive phylogenetic analysis of basal iguanodont relationships. This analysis indicates that North American Early Cretaceous basal iguanodonts are more basal than their contemporaries in Europe and Asia.
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ABSTRACT: Nodular carbonates (‘‘calcretes’’) in continental foreland-basin strata of the Early Cretaceous Cedar Mountain Formation (CMF) in eastern Utah yield d13C and d18O records of changes in the exogenic carbon cycle related to oceanic anoxic events (OAEs), and terrestrial paleoclimate. Chemostratigraphic profiles of both forebulge and foredeep sections show two prominent positive d13C excursions, each with a peak value of 23% VPDB, and having background d13C values of about 26% VPDB. These excursions correlate with the global early Aptian (Ap7) and late Aptian–early Albian (Ap12–Al1) carbon isotope excursions. Aptian–Albian positive d13C excursions in the CMF also correspond to 3–4 per mil increases in carbonate d18O. These phenomena record local aridification events. The chemostratigraphic profile on the thinner forebulge section of the CMF is calibrated, for the first time, by a radiogenic U-Pb date of 119.4 ± 2.6 Ma on a carbonate bed, and by detrital zircon U-Pb dates on two bounding sandstone units (maximum depositional ages of 146 Ma and 112 Ma). Petrographic observations and diagenetic analyses of micritic to microsparitic carbonates from nodules indicate palustrine origins and demonstrate that they crystallized in shallow early meteoric phreatic environments. Meteoric calcite lines derived from CMF carbonates have d18O values ranging between 28.1 to 27.5% VPDB, supporting an estimate of zonal mean groundwater d18O of 26% VSMOW for an Aptian–Albian paleolatitude of 34u N. Furthermore, our two chemostratigraphic profiles exhibit a generally proportionate thinning of correlative strata from the foredeep on to the forebulge, suggesting that there were consistently lower rates of accumulation on the forebulge during the Aptian–Albian. Identification of the global Aptian–Albian d13C excursions in purely continental strata, as demonstrated in this paper, opens a new avenue of research by identifying specific stratigraphic intervals that record the terrestrial paleoclimatic impacts of perturbations of the global carbon cycle.

"A PRIMITIVE THERIZINOSAUROID DINOSAUR FROM THE EARLY CRETACEOUS OF UTAH

KIRKLAND, JAMES I. Utah Geological Survey, PO Box 146100, Salt Lake City, UT
ZANNO, LINDSAY E. Utah Museum of Natural History and Department of Geology and Geophysics, University of Utah, 1390 E. Presidents Circle, Salt Lake City, UT
SAMPSON, SCOTT D. Utah Museum of Natural History and Department of Geology and Geophysics, University of Utah, 1390 E. Presidents Circle, Salt Lake City, UT
CLARK, JAMES M. George Washington University, Washington D.C.
DEBLIEUX, DONALD Utah Geological Survey, PO Box 146100, Salt Lake City, UT

Therizinosauroids are an enigmatic group of dinosaurs known from the Cretaceous of Asia and North America whose derived members are characterized by elongate necks, laterally expanded pelves, small, leaf-like teeth, and edentulous rostra and mandibular symphyses that probably bore keratinized beaks.  Although over a dozen therizinosauroid taxa have been described, the fragmentary nature of their remains, together with an unusual suite of morphological characters, has fueled controversy over their relationships within Dinosauria.  The primitive therizinosauroid Beipiaosaurus from China, preserved with feather-like impressions, recently clarified the theropod affinities of the group.  Here we describe a new therizinosauroid from the Early Cretaceous of east-central Utah more primitive than Beipiaosaurus. Phylogenetic analysis of coelurosaurian theropods incorporating this taxon places it at the base of Therizinosauroidea and strongly supports origination of this clade within maniraptoran theropods as the sister-group of Oviraptorosauria.  The new taxon represents the most complete and most basal therizinosauroid discovered to date.  This species documents a transition from carnivory to herbivory within the Therizinosauria and indicates a previously unrecognized pan-Laurasian distribution for therizinosauroids during the Early Cretaceous.
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Protoceratops skeletons preserved in the Upper Cretaceous Djadokhta Formation and its correlatives in central Asia are often associated with trace fossils such as borings and diagenetically enhanced burrows in the surrounding rock. An articulated skeleton of a Protoceratops, uncovered at Tugrugiin Shireh, Mongolia, documents the association of both insect borings and casts of insect pupation chambers with a dinosaur skeleton for the first time. Documentation of the prevalence of borings associated with many of the articulated skeletons in these rocks indicates a significant ecological relationship between dinosaurs and necrophagous insects in an eolian setting.

The National Park Service (NPS) administers 13 park units within the state of Utah.  Most of these parks, monuments, and other NPS units have been established and are recognized for their significant geologic features.  Fossiliferous rocks of Paleozoic, Mesozoic, and Cenozoic age have been identified in all of the National Park System units in Utah.  In 1998, the first comprehensive inventory of paleontological resources in the national parks and monuments of Utah was initiated.  A wide diversity of fossilized plants, invertebrates, vertebrates, and trace fossils has been documented.  Paleontological resources identified from within the parks and monuments have been assessed relative to their scientific significance, potential threats, and management as non-renewable resources.  Considerable focus has been directed towards the in situ management of the abundant fossil vertebrate tracks identified throughout the Mesozoic formations within at least seven National Park Service areas in Utah.  The baseline paleontological resource data obtained during this inventory will assist park staff with improved management of their paleontological resources and protection of fossils within their park.