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On September 18, 1996, Grand Staircase-Escalante National Monument (GSENM) became the first national monument managed by the US Bureau of Land Management (BLM) and one of the first to protect a landscape based partly on its opportunity for scientific discovery. Its creation was a watershed moment in public land management, because to meet the mandates for its first monument, BLM opted to implement unprecedented support of resource investigations for numerous natural and cultural sciences, including establishing its first ever in-house paleontological field program. The rationale for this was taken directly from the establishing presidential proclamation (6920) which called out GSENM’s untapped paleontological treasure trove as “world-class.” The proclamation also singled out the Late Cretaceous vertebrate fossil record of the Kaiparowits Plateau, largely known at the time through the pioneering work of Drs. Jeff Eaton and Rich Cifelli, who had spent years teasing out the mammalian evolutionary story preserved within. Their work on Mesozoic mammals, alongside sporadic work by other institutions (mainly the University of Utah and Brigham Young University) in the 1970s and 1980s, demonstrated that the Kaiparowits Plateau also held a substantial macrovertebrate record that included beautifully preserved dinosaur skeletons. However, a lack of coordinated effort and the difficult nature of fieldwork in the rugged badlands led to what can only be described as desultory results. The leverage that came with monument status, including logistical and financial support provided by BLM, made this resource more accessible to the paleontological community, stimulating a sudden burst of new field research and discovery. Initial, coordinated, and collaborative fossil inventories started in 2000 by joint BLM, Utah Museum of Natural History, Museum of Northern Arizona, and Utah Geological Survey teams led to a cascade of discoveries, including sites preserving plants, invertebrates, trace fossils, microvertebrates, and macrovertebrates, contextualized by new geological insights. Many of these new fossil finds represent species entirely new to science, with some sites preserving intact snapshots of Late Cretaceous ecosystems that are unmatched globally. Unique geologic conditions resulted in spectacular preservation, sometimes even including soft tissue traces. This renaissance in North American Late Cretaceous paleontology would not have been possible without the focused resources and effort facilitated by the creation of GSENM and the subsequent prioritization of inventory and basic research in its mission. In addition to the science, the public benefits of these efforts have been immense, providing opportunities for direct involvement in the scientific process through volunteer programs, training for several generations of future paleontologists and geologists, innumerable educational programs, and exposure in national and international media outlets through articles, television, and interviews. The collaborative and far-reaching paleontological effort at GSENM has highlighted an often overlooked aspect of public lands management: the importance of US public lands for scientific discovery and education. 

Monstersauria (Squamata, Anguimorpha) fossils are present in most Upper Cretaceous sedimentary basins in western North America, but despite almost a century of collection, their record remains extremely fragmentary. Here, we describe new material belonging to large-bodied monstersaurs, including a new taxon,Bolg amondolgen. et sp. nov., based on a fragmentary associated skeleton and co-occurring specimens from the middle unit of the upper Campanian Kaiparowits Formation of Grand Staircase–Escalante National Monument in southern Utah, USA. Phylogenetic analyses recoverB. amondolwithin Monstersauria, with two unique anatomical features: fused osteoderms on the jugal and the presence of autotomy septa on the distal caudal vertebrae. Critically,B. amondolis morphologically distinct from the problematic Late Cretaceous North American monstersaurPalaeosaniwa canadensis, whereas co-occurring monstersaur vertebrae and parietals from the Kaiparowits Formation (cf.P. canadensis) highlight a pressing need for a reassessment of this important, widespread taxon. These results offer new evidence that at least three lineages of distinct, large-bodied monstersaurian lizard were present on the palaeolandmass of Laramidia during the Campanian Stage. Importantly,B. amondolrepresents the most complete squamate recovered from late Campanian southern Laramidia and reveals key anatomical characteristics for future identification of isolated lizard fossil elements. 

Eopneumatosuchus colberti Crompton and Smith, 1980, known from a single partial skull, is an enigmatic crocodylomorph from the Lower Jurassic Kayenta Formation. In spite of its unique morphology, an exceptionally pneumatic braincase, and presence during a critical time period of crocodylomorph evolu- tion, relatively little is known about this taxon. Here, we redescribe the external cranial morphology of E. colberti, present novel information on its endocranial anatomy, evaluate its phylogenetic position among early crocodylomorphs, and seek to better characterize its ecology. Our examination clarifies key aspects of cranial suture paths and braincase anatomy. Comparisons with related taxa (e.g., Protosuchus haughtoni) demonstrate that extreme pneumaticity of the braincase may be more widespread in protosuchids than previously appreci- ated. Computed tomography scans reveal an endocranial morphology that resembles that of other early crocodylomorphs, in particular the non- crocodyliform crocodylomorph Almadasuchus figarii. There are, however, key differences in olfactory bulb and cerebral hemisphere morphology, which dem- onstrate the endocranium of crocodylomorphs is not as conserved as previously hypothesized. Our phylogenetic analysis recovers E. colberti as a close relative of Protosuchus richardsoni and Edentosuchus tienshanensis, contrasting with previous hypotheses of a sister group relationship with Thalattosuchia. Previ- ous work suggested the inner ear has some similarities to semi-aquatic crocodyliforms, but the phylogenetic placement of E. colberti among proto- suchids with a terrestrial postcranial skeletal morphology complicates paleo- ecological interpretation. 

The femora of diapsids have undergone morphological changes related to shifts in postural and locomotor modes, such as the transition from plesiomorphic amniote and diapsid taxa to the apomorphic conditions related to a more erect posture within Archosauriformes. One remarkable clade of Triassic diapsids is the chameleon-like Drepanosauromorpha. This group is known from numerous articulated but heavily compressed skeletons that have the potential to further inform early reptile femoral evolution. For the first time, we describe the three-dimensional osteology of the femora of Drepanosauromorpha, based on undistorted fossils from the Upper Triassic Chinle Formation and Dockum Group of North America. We identify apomorphies and a combination of character states that link these femora to those in crushed specimens of drepanosauromorphs and compare our sample with a range of amniote taxa. Several characteristics of drepanosauromorph femora, including a hemispherical proximal articular surface, prominent asymmetry in the proximodistal length of the tibial condyles, and a deep intercondylar sulcus, are plesiomorphies shared with early diapsids. The femora contrast with those of most diapsids in lacking a crest-like, distally tapering internal trochanter. They bear a ventrolaterally positioned tuberosity on the femoral shaft, resembling the fourth trochanter in Archosauriformes. The reduction of an internal trochanter parallels independent reductions in therapsids and archosauriforms. The presence of a ventrolaterally positioned trochanter is also similar to that of chameleonid squamates. Collectively, these features demonstrate a unique femoral morphology for drepanosauromorphs, and suggest an increased capacity for femoral adduction and protraction relative to most other Permo-Triassic diapsids. 

Abstract. The upper Paleozoic Cutler Group of southern Utah, USA, is a key sedimentary archive for understanding the Earth-life effects of the planet's last pre-Quaternary icehouse–hothouse state change: the Carboniferous–Permian (C–P) transition, between 304 and 290 million years ago. Within the near-paleoequatorial Cutler Group, this transition corresponds to a large-scale aridification trend, loss of aquatic habitats, and ecological shifts toward more terrestrial biota as recorded by its fossil assemblages. However, fundamental questions persist. (1) Did continental drift or shorter-term changes in glacio-eustasy, potentially driven by orbital (Milankovitch) cycles, influence environmental change at near-equatorial latitudes during the C–P climatic transition? (2) What influence did the C–P climatic transition have on the evolution of terrestrial ecosystems and on the diversity and trophic structures of terrestrial vertebrate communities? The Paleozoic Equatorial Records of Melting Ice Ages (PERMIA) project seeks to resolve these issues in part by studying the Elk Ridge no. 1 (ER-1) core, complemented by outcrop studies. This legacy core, collected in 1981 within what is now Bears Ears National Monument, recovered a significant portion of the Hermosa Group and the overlying lower Cutler Group, making it an ideal archive for studying paleoenvironmental change during the C–P transition. As part of this project, the uppermost ∼ 450 m of the core were temporarily transferred from the Austin Core Repository Center to the Continental Scientific Drilling Facility at the University of Minnesota for splitting, imaging, and scanning for geophysical properties and spectrophotometry. Here we (1) review the history of this legacy core, (2) introduce recently obtained geophysical and lithologic datasets based on newly split and imaged core segments to provide a sedimentological and stratigraphic overview of the Elk Ridge no. 1 core that aligns more accurately with the currently recognized regional lithostratigraphic framework, (3) establish the position of the boundary between the lower Cutler beds and the overlying Cedar Mesa Sandstone in the core, and (4) outline our ongoing research goals for the core. In-progress work on the core aims to refine biostratigraphic and chemostratigraphic age constraints, retrieve the polarity stratigraphy, interrogate preserved cyclostratigraphy, analyze sedimentary structures and paleosol facies, investigate stable isotope geochemistry, and evaluate elemental abundance data from X-ray fluorescence (XRF) scanning. Together with outcrop studies throughout Bears Ears National Monument and its vicinity, these cores will allow the rich paleontological and paleoenvironmental archives recorded in the continental Carboniferous–Permian transition of western North America to be confidently placed in a robust chronologic context that will help test hypotheses relating ecosystem evolution to the Carboniferous rainforest collapse, initial decline of the Late Paleozoic Ice Age, and long-wavelength astronomical cycles pacing global environmental change.