At the heart of the society’s argument is a deceptively simple scientific principle: context matters. Both monuments, the organization emphasizes, were originally delineated not as arbitrary parcels of land but as geologically coherent landscapes, where the boundaries were drawn to preserve the spatial continuity essential for reading Earth’s history the way one reads a book. Remove chapters from the middle of that book, geologists argue, and the remaining pages lose much of their meaning. The exposed rock sequences in these monuments do not merely document ancient environments in isolation; they preserve the relationships between layers, the transitions between time periods, and the physical evidence of the enormous forces that shaped the Colorado Plateau over hundreds of millions of years.

Grand Staircase–Escalante National Monument, designated in 1996, is perhaps the most dramatic illustration of this principle. The monument takes its name from the vast sequence of cliffs and terraces—the Grand Staircase itself—that steps progressively through roughly two billion years of layered sedimentary rock, from the ancient Vishnu Schist at the base of the Grand Canyon region up through the pastel-hued strata of Bryce Canyon’s rim. Across this landscape, geologists can trace the interplay of dramatic uplift and erosion that has raised the entire Colorado Plateau by thousands of feet while rivers carved away at it, exposing layer after layer of rock that records shifting seas, migrating shorelines, evolving river systems, and the rise and fall of entire ecosystems.

Within the monument, the Kaiparowits Plateau has emerged as an internationally celebrated destination for paleontological research. The Late Cretaceous rocks of the Kaiparowits Formation preserve an extraordinarily rich record of dinosaurs and other organisms that lived on a portion of the ancient continent of Laramidia, a landmass isolated from the rest of North America by a seaway that bisected the continent more than 75 million years ago. Discoveries from this region—including previously unknown species of horned dinosaurs, duck-billed dinosaurs, and tyrannosaurs—have fundamentally reshaped scientific understanding of how dinosaur ecosystems were structured and how they evolved during the final chapters of the Mesozoic Era. Researchers have consistently emphasized that this record is valuable precisely because the rocks remain intact, exposed, and embedded within a landscape whose geological relationships have not been fragmented.

Bears Ears National Monument, designated in 2016 and notable for being established at the request of a coalition of five Tribal Nations, tells an even deeper story in geological time. The monument’s deeply eroded terrain on the Colorado Plateau preserves more than 300 million years of Earth history, but its scientific crown jewel is what geologists consider one of the finest continuous records anywhere in the world of the Triassic–Jurassic transition. This interval, roughly 201 million years ago, marks one of the five greatest mass extinctions in Earth’s history—an event triggered by massive volcanic eruptions associated with the breakup of the supercontinent Pangaea that eliminated perhaps three-quarters of all species on the planet. The sequences of rock in Bears Ears capture this pivotal moment with a continuity that allows scientists to study how ecosystems collapsed, recovered, and reorganized, offering essential baseline knowledge for understanding how life responds to global environmental upheaval.

The Geological Society’s statement also makes an explicit connection between the monuments’ geology and their celebrated archaeological heritage. Bears Ears contains tens of thousands of cultural sites, including cliff dwellings, kivas, and rock art panels that testify to ancestral Puebloan and other Indigenous communities. But these human records, the society notes, are physically anchored to the landscape itself. Ancient peoples built their dwellings from local stone, sheltered beneath the same overhanging sandstone ledges, and followed water sources whose existence was dictated by the underlying geology. Understanding the archaeological record therefore requires understanding the geological setting that made human habitation possible—and that setting, like the rock record itself, is legible only when the landscape remains whole. Fragmenting the monument, scientists argue, inevitably fragments this interwoven record of geological and human history.

The statement is notable for the way it anticipates and directly addresses the most common economic argument for reducing the monuments: access to mineral and energy resources. Rather than dismissing resource development outright, the Geological Society of America affirms that it recognizes the national importance of mineral resources and the central role that geoscientists themselves play in their responsible development. But, the society argues, responsible development cannot mean sacrificing irreplaceable scientific and geoheritage resources to irreversible damage. Mineral deposits, however valuable, are quantifiable and recoverable in other locations; the fossil localities, stratigraphic sections, and geological exposures within these monuments, once destroyed by roads, mining operations, or off-road vehicle activity, can never be restored to their scientific state. The statement effectively reframes the debate as one not of science versus economy, but of short-term extraction versus permanent loss of a shared national and scientific inheritance.

The reductions to both monuments have been among the most contentious public-lands decisions in modern American history. Bears Ears was reduced by approximately 85 percent, and Grand Staircase–Escalante by roughly half, opening former monument lands to potential mining, drilling, and other development. Those reductions have been challenged in federal court by a coalition of plaintiffs that has included Tribal Nations, conservation organizations, and scientific societies, and the legal battles have repeatedly underscored questions about presidential authority under the Antiquities Act of 1906—the statute that authorizes presidents to protect objects of historic and scientific interest on federal lands. The Geological Society’s statement directly acknowledges this ongoing litigation, noting that the reductions remain contested in the courts, and the society’s intervention adds significant scientific weight to those proceedings.

Beyond the legal and political dimensions, the society’s statement is also a defense of the practice of field science itself. Both monuments function as living laboratories where generations of geologists and paleontologists have been trained—where students learn to read rock exposures, reconstruct ancient landscapes, and test hypotheses against the physical evidence preserved in stone. Grand Staircase–Escalante alone has yielded hundreds of new fossil species, many of them discovered through systematic fieldwork that depends on access to broad, intact tracts of land. The society emphasizes that these landscapes support ongoing scientific discoveries even today, and that cutting their boundaries would undermine not only current research but the training of future generations of geoscientists who will need such natural laboratories to confront emerging questions about climate change, evolution, and deep-Earth processes.

The organization closes its statement with an unambiguous call: the monuments’ boundaries should be restored, and their long-term stewardship should reflect the irreplaceable scientific and cultural value of these landscapes. The Geological Society of America, with more than 18,000 members in over 100 countries and publisher of the top-ranked journal Geology, speaks with considerable authority on questions of geological significance. Its formal opposition signals that the scientific community regards these monuments not as contested political terrain but as essential instruments of knowledge—irreplaceable archives of more than 300 million years of Earth history, and landscapes whose full meaning, like the rock layers that compose them, can only be understood when they are preserved intact.

The specimen of Bolg amondol was initially uncovered in museum collections, a testament to the invaluable scientific potential buried within natural history institutions. Despite being fragmentary, the associated skeleton includes a broad range of bones such as pieces of the skull, vertebrae, girdles, limbs, and osteoderms—peculiar bony armor plating that stands as a defining trait of monstersaurs. What makes this find even more exceptional is that these fragments likely belong to a single individual, rather than a jumbled assemblage from multiple animals, enabling scientists to reconstruct significant anatomical and evolutionary details with greater confidence.

Lead author Dr. Hank Woolley of the Natural History Museum of Los Angeles County’s Dinosaur Institute emphasized the rarity and scientific importance of large-bodied lizard fossils from the Kaiparowits Formation. “The fragmentary nature of most fossil lizards means finding nearly complete associated specimens is extraordinary,” Woolley explains. “This completeness allows us to examine morphological traits across the skeleton, which sheds light on where Bolg fits within the larger lizard evolutionary tree.” The detailed characterization reveals both commonalities and unique features that align Bolg with other monstersaurs, further refining their classification and evolutionary history.

Monstersaurs, as a group, have remained enigmatic over millions of years, partly due to their sparse and fragmentary fossil records. These lizards are generally recognized by their distinctive armor—pitted and polygonal osteoderms fused to the skull—and sharp, spire-like teeth designed for a predatory lifestyle. The discovery of Bolg—estimated to be around three feet from tip to tail—confirms that large monstersaurs were not only present but diversified significantly within late Cretaceous ecosystems. This size corresponds roughly to that of a modern Savannah monitor lizard, indicating these creatures were formidable mid-level predators, likely hunting small vertebrates and eggs.

The implications of this discovery extend beyond taxonomy and anatomy, touching on ancient biogeography and ecosystem dynamics. Intriguingly, Bolg’s closest known relatives hail from the Gobi Desert in Asia, suggesting faunal exchanges between continents during the Late Cretaceous. These connections, once predominantly documented among dinosaur species, now appear more widespread among smaller terrestrial vertebrates such as lizards. This indicates complex dispersal pathways and ecological interactions shaping the prehistoric world at large.

Co-author Dr. Randy Irmis from the University of Utah highlights the instrumental role of paleontological collections in fostering such discoveries. Specimens collected years ago can reside in museum drawers for decades, their scientific value undisclosed until a specialist reevaluates them with fresh perspectives and techniques. The description of Bolg epitomizes how meticulous research on fragmentary remains can yield transformative insights into biodiversity and evolutionary relationships of ancient life.

Beyond the specimen itself, associated fossils from the Kaiparowits Formation include remarkably armored skull bones belonging to at least two other large lizard species. This assemblage paints a picture of a thriving community of predatory reptiles occupying diverse niches in a dinosaur-dominated environment. Researchers suggest these monstersaurs played significant ecological roles as secondary predators, perhaps specializing in raiding dinosaur nests or preying on small animals, thus intricately entwining with the trophic webs of their ecosystems.

The Kaiparowits Formation, noted for its rich paleontological record, serves as a critical window into Late Cretaceous terrestrial life in North America. Over the past quarter-century, it has produced a wealth of new species, revealing dynamic and complex ecosystems that evolved amidst fluctuating climatic and geological conditions. Discoveries like Bolg amondol underscore the necessity of preserving such public lands—not merely as reservoirs of natural beauty but as crucial scientific archives that hold answers about Earth’s deep past.

The research presented by Woolley and colleagues was supported by multiple institutions and funding bodies, including the National Science Foundation, the Bureau of Land Management, and the Natural History Museum of Los Angeles County. This collaboration exemplifies the synergy between fieldwork, museum curation, and cutting-edge analytical methods, demonstrating that significant paleontological breakthroughs often arise from the intersection of these domains.

On a broader scale, the unveiling of Bolg challenges previous assumptions regarding the diversity and evolutionary complexity of large-bodied lizards during the dinosaur era. It invites a reevaluation of their ecological significance as more than mere background fauna. The distinctive osteoderms and predatory adaptations of monstersaurs indicate specialized evolutionary paths, paralleling those of better-known contemporaneous vertebrate groups.

Moreover, the creative use of Tolkien’s Sindarin language to name the species reflects the scientific community’s embrace of cultural elements to evoke the striking morphology and character of these animals. The “Mound-Headed Goblin” nomenclature poetically captures the essence of the species’ distinctive skull armor while linking science and imagination in a way that resonates beyond academic circles.

This groundbreaking discovery encourages ongoing exploration within museum collections worldwide and field expeditions across protected lands. As many fossil specimens remain unstudied in drawers, the potential for revealing hidden chapters of Earth’s biological heritage is immense. Such discoveries not only deepen scientific knowledge but also inspire public fascination with the origins and evolution of life on our planet.

In summation, Bolg amondol is not just another entry in the fossil record; it represents a significant stride toward unraveling the diversity, adaptation, and biogeographical history of monstersaurs during the Late Cretaceous. It stands as a reminder that even small fragments of bone can illuminate vast evolutionary narratives, an enduring testament to the enduring value of museum collections and collaborative scientific inquiry.

Subject of Research: Animals

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

News Publication Date: 17-Jun-2025

Web References: http://dx.doi.org/10.1098/rsos.250435

Image Credits: Art by Cullen Townsend

Keywords: Monstersauria, Late Cretaceous, Kaiparowits Formation, Grand Staircase-Escalante, Paleontology, Lizards, Fossil Discovery, Dinosaur-era Predators, Osteoderms, Biogeography, Natural History Museum Collections, Bolg amondol