The study is the first to use fossilized leaf cells to estimate the Leaf Area Index, or LAI, of a forest from deep time. LAI measures the total leaf area above a given unit of ground and is widely used to describe canopy density. A high LAI indicates a multilayered forest with abundant foliage, while a low LAI corresponds to a more open woodland or sparse vegetation. Modern satellites track changes in global LAI, but until now, researchers lacked a comparable quantitative method for reconstructing canopy structure across geological timescales. By extracting information from microscopic leaf fragments preserved in ancient soils, the team created a new window into how forests responded to an extreme carbon-driven climate event.

The PETM began approximately 56 million years ago and lasted for tens of thousands of years, although the initial carbon release occurred rapidly by geological standards. Atmospheric temperatures increased sharply, high-latitude regions became unusually warm, and rainfall patterns shifted across continents. The new analysis suggests that these changes did not simply alter the species composition of forests; they transformed the physical architecture of entire landscapes. As vegetation migrated toward cooler regions, canopy cover declined, erosion intensified, and the terrestrial water cycle was disrupted. The result was what the researchers describe as a widespread “browning” of Earth’s landscapes, with fewer large trees and more open forest structure.

The research team developed its fossil-canopy reconstruction by studying modern forests in South and Central America. In each contemporary ecosystem, the researchers photographed the canopy from below using a fisheye lens pointed upward. These images allowed them to calculate LAI by measuring how much of the sky was blocked by leaves and branches. At the same time, they collected soil samples beneath the photographed canopies and isolated fragments of leaf cuticle—the durable, waxy outer layer of leaves that can survive after other plant tissues decay. By comparing the microscopic anatomy of the modern cuticle fragments with the measured LAI values above them, the scientists established a calibration model that could later be applied to fossil material.

The key biological signal came from the shape of epidermal cells, the microscopic units forming the outer surface of a leaf. Leaves growing in bright, exposed positions near the tops of trees tend to develop relatively broad epidermal cells. Leaves growing in the shade of a dense canopy respond differently: their cells become longer and more slender, increasing their aspect ratio as the plant adjusts to limited sunlight. Although the leaves eventually fall and break apart in the soil, the shapes of these cells can remain preserved in cuticle fragments. By measuring thousands of fossilized cells and applying the modern calibration, the researchers could estimate how dense the ancient canopy had been when those leaves were alive.

The fossil evidence came from Wyoming’s Hanna Basin, a coal-forming region containing organic-rich rocks that preserve plant material from before, during, and after the PETM. The basin’s lignites and coals retain leaf fragments that are rare or poorly preserved in many other sites containing the same climate interval. More than a decade of fieldwork produced hundreds of samples from the basin, documenting forests that were dramatically different from the sagebrush-dominated landscape found in Wyoming today. Ancient dawn redwoods, sycamores, alders, palms, and other subtropical and tropical plants formed a complex vegetation system around lakes, wetlands, and floodplains.

When the team compared canopy estimates across the PETM interval, the pattern was pronounced: forest LAI fell, indicating a more open canopy with less foliage overhead. The decline implies that forests contained fewer large trees or experienced greater spacing between trees, or both. Such structural changes would have affected far more than the plants themselves. Open canopies allow more sunlight to reach the ground, increase evaporation from soils, and expose organic matter to heat and drying. They can also accelerate surface runoff and erosion, alter nutrient transport, and reduce the capacity of forests to recycle water into the atmosphere through transpiration. The decline in canopy density therefore represents a broad ecosystem shift rather than a simple change in tree abundance.

The ancient findings carry an urgent modern implication because contemporary carbon emissions are occurring at a rate far beyond the natural carbon release associated with the PETM. Human activities are raising atmospheric carbon dioxide roughly an order of magnitude faster than the ancient episode, while forests are simultaneously being exposed to warming temperatures, drought, wildfire, insects, pathogens, habitat fragmentation, and land-use change. Carbon dioxide can initially stimulate plant growth, a phenomenon reflected in decades of global “greening” detected by satellites. Yet as temperatures rise and water stress intensifies, that fertilization effect can be overwhelmed. In many regions, forest productivity is now weakening, tree mortality is increasing, and landscapes are beginning to brown.

“Earth has been on a greening trajectory because of anthropogenic carbon dioxide emissions that have fertilized plants,” said lead author Regan Dunn, a paleobotanist and associate curator at the Natural History Museum of Los Angeles County. “But as Earth has heated up because of those emissions, this greening trend is reversing, and many parts of Earth are now browning.” The PETM record suggests that forests can cross a threshold at which additional heat and drying cause their structure and function to deteriorate. Co-author Ellen D. Currano of the University of Wyoming said the ancient evidence shows that excessive carbon dioxide, accompanied by warming and drying, can reduce plant growth, biomass, and productivity while changing climate, nutrient cycling, weathering, and the habitats available to animals.

The researchers emphasize that the PETM is not a perfect duplicate of the present. The ancient world had different continents, ecosystems, atmospheric conditions, and rates of environmental change, while today’s forests face direct human destruction in addition to climate stress. Nevertheless, the fossil canopy provides a rare empirical test of how forests respond when carbon levels rise and temperatures increase across a sustained interval. Trees currently remove hundreds of millions of tons of carbon from the atmosphere each day, but that service depends on healthy, functioning forests. If warming and drought continue to reduce canopy cover, forests may absorb less carbon precisely when society most needs them to do so. The ancient Wyoming record thus turns microscopic fragments of leaf tissue into a warning visible at planetary scale: protecting and restoring forests may be essential to preventing a climate feedback in which damaged ecosystems release carbon and lose their ability to buffer further warming.

Subject of Research: Cells

Article Title: Forest canopy decline under elevated CO2 during the Paleocene-Eocene Thermal Maximum

News Publication Date: 13-Aug-2026

Web References: https://www.science.org/doi/10.1126/science.aec4776

References: Science; DOI: 10.1126/science.aec4776

Image Credits: Dr. Regan Dunn

Keywords: Paleocene-Eocene Thermal Maximum, PETM, forest canopies, climate change, carbon dioxide, global warming, leaf area index, LAI, fossilized leaf cuticle, paleobotany, tree mortality, forest browning, Wyoming, ecosystem change, carbon cycle

Using an integrated analysis of the marine fossil record, the authors compared biodiversity patterns against inferred periods of ecosystem engineering. Ecosystem engineers are species or communities that physically modify habitats—creating structure, regulating resources, and reshaping local environmental conditions. In effect, they act as living infrastructure, altering ecological “terrain” on which other organisms depend.

A central finding is that engineer-linked intervals show stronger biodiversity signals than times lacking such activity. The pattern holds across vast geological intervals, suggesting that engineering effects are not merely local anomalies but recurring drivers of marine richness. This implies that habitat complexity and availability, both tightly linked to ecosystem engineering, can buffer communities against long-term environmental volatility.

Technically, the study leverages statistical frameworks designed to disentangle confounding signals in deep-time datasets. By focusing on co-occurrence relationships between engineer activity and biodiversity outcomes, the authors aim to capture how ecosystem modification propagates through trophic networks. The analysis further considers how large-scale shifts—such as changes in sea level and climate—could influence both engineering organisms and the taxa that respond to them.

The authors’ approach supports a mechanism-based interpretation: engineered habitats can expand niche space, stabilize living conditions, and improve settlement opportunities for dependent species. Over evolutionary timescales, these processes can amplify diversification by increasing both survival probabilities and access to resources.

Importantly, the results suggest that ecosystem engineers may have helped maintain ecological resilience during periods of upheaval. Rather than acting as passive bystanders to mass extinctions, engineers may have provided persistent habitat structure, enabling marine communities to rebound more effectively.

Taken together, the study positions ecosystem engineers as key long-term determinants of marine biodiversity. For evolutionary biology and conservation alike, the message is clear: protecting habitat-shaping species may preserve more than their own populations—it may safeguard entire community futures.

Subject of Research: Marine biodiversity and ecosystem engineering across the Phanerozoic

Article Title: Marine biodiversity was greater in the presence of ecosystem engineers throughout the Phanerozoic

Article References: Cribb, A.T., Darroch, S.A.F. & Gearty, W. Marine biodiversity was greater in the presence of ecosystem engineers throughout the Phanerozoic. Nat Commun (2026). https://doi.org/10.1038/s41467-026-73628-6

Image Credits: AI Generated

DOI: 10.1038/s41467-026-73628-6

Keywords: Marine biodiversity; ecosystem engineers; Phanerozoic; fossil record; habitat complexity; ecological resilience

The Ediacaran period, spanning roughly from 635 to 541 million years ago, marks the dawn of multicellular life and set the stage for the rapid diversification of animals in the Cambrian. Despite decades of geological and paleontological research, many questions still surround the ecological dynamics and biological complexity of this era. The Tongshan Lagerstätte, situated in South China’s rich fossil-bearing strata, stands out for its exquisite preservation of soft-bodied organisms—often elusive in the fossil record. Such preservation allows scientists to decode morphological features with an extraordinary level of detail, surpassing that of typical fossil assemblages reliant mostly on mineralized parts.

The newly documented Tongshan Lagerstätte fossils include a diverse assemblage of soft-bodied organisms, ranging from enigmatic tubular forms to possible early metazoans. Particularly striking is the level of anatomical complexity observed, which indicates sophisticated biological organization had already evolved by the latest Ediacaran times. These findings challenge previously held assumptions that late Ediacaran organisms were primarily simple, immobile life forms. Instead, the fossils reveal a dynamic ecosystem possibly featuring motility and more overt ecological interactions such as predation and competition, aspects usually attributed to later periods.

Cutting-edge analytical techniques played a pivotal role in this study, including micro-CT scanning and high-resolution microscopy. These methods enabled the team to reconstruct three-dimensional morphologies in unprecedented detail, preserving fragile structures that conventional fossil preparation would likely destroy. This detailed morphological data allows for refined phylogenetic comparisons, helping to clarify evolutionary relationships among enigmatic Ediacaran taxa. The researchers leveraged these insights to propose a more nuanced view of early metazoan evolution, placing some Tongshan organisms closer to modern lineages than previously recognized.

The depositional environment of the Tongshan Lagerstätte also offers critical clues to the ecological context during the terminal Ediacaran. Sedimentological and geochemical analyses suggest that these fossils formed in a shallow marine setting with episodic anoxic conditions. Such an environment might have facilitated exceptional preservation by limiting decomposition and bioturbation. Furthermore, these conditions underscore the ecological stresses and environmental variability facing late Ediacaran life forms, potentially driving evolutionary innovations observed in these fossil assemblages.

One of the most compelling facets of the study is the temporal placement of the Tongshan Lagerstätte. The fossils date to the very end of the Ediacaran, shedding light on the biological and ecological scenarios immediately preceding the Cambrian Explosion—the period widely regarded as the most dramatic diversification of animal life. Understanding the transition between these two periods is essential for piecing together how complex multicellular animals emerged and rose to ecological prominence. The Tongshan fossils offer a rare snapshot of this evolutionary watershed moment, revealing the intricate interplay between biology and environment.

The implications of this research extend beyond paleontology into evolutionary biology and Earth system science. By deciphering how terminal Ediacaran organisms adapted and diversified under specific environmental conditions, the study provides a model for how life responded to global changes in Earth’s systems at the Neoproterozoic-Cambrian boundary. This knowledge is crucial for reconstructing the broader narrative of life’s resilience and adaptability, themes that resonate as contemporary ecosystems face rapid climatic and environmental shifts.

Moreover, the Tongshan Lagerstätte facilitates a robust comparison with contemporaneous fossil assemblages worldwide, fostering a more integrated global perspective on Ediacaran biodiversity. Previous discoveries from regions such as Newfoundland, Namibia, and Australia have highlighted regional variation in organismal forms and ecosystems. The South China fossils add a vital piece to this puzzle, expanding the biogeographic and evolutionary context. Such data help dispel notions that Ediacaran life forms were uniform and globally homogenous, demonstrating instead diverse evolutionary experiments occurring across different paleoenvironments.

The research team behind this discovery comprises experts in paleobiology, geochemistry, and sedimentology, whose interdisciplinary approach enriched the study’s scope and depth. Their collaborative efforts exemplify how combining diverse expertise can unravel the complexity of ancient life and Earth’s history. The comprehensive dataset, including fossil morphology, stratigraphy, and geochemical signatures, builds a compelling narrative that situates the Tongshan Lagerstätte as a keystone locality for unraveling the terminal Ediacaran mystery.

Importantly, the Tongshan Lagerstätte’s contributions are not limited to descriptive paleontology but also challenge prevailing evolutionary models. The presence of more complex anatomical structures and inferred ecological roles forces revisions of how early metazoans evolved and interacted. Notably, these fossils indicate that ecological drivers such as predation and locomotion may have been significant much earlier than traditionally assumed. This realization urges the scientific community to reassess timelines and mechanisms underlying early animal evolution and ecosystem establishment.

In addition to biological insights, the study provides methodological advancements that could revolutionize future fossil research. By harnessing the power of non-destructive imaging techniques within a multidisciplinary framework, the researchers set a new standard for investigating exceedingly delicate fossils. These technologies promise to unlock fossil data previously inaccessible, paving the way for discoveries in other Lagerstätten worldwide. Consequently, the Tongshan Lagerstätte stands as a model for future paleontological explorations, emphasizing detailed anatomical resolution combined with precise environmental contextualization.

The discovery also invigorates broader discussions about the biotic and abiotic factors influencing the Neoproterozoic-Cambrian transition. By evidencing how environmental fluctuations linked with ocean chemistry and sediment dynamics affected biological communities, the study underscores the importance of Earth system feedbacks in shaping life’s trajectory. This perspective highlights the co-evolution of life and environment, suggesting that evolutionary innovation is intimately tied to Earth’s changing geochemical landscapes, a notion with implications for understanding planetary habitability in deep time.

Furthermore, the Tongshan Lagerstätte’s fossils contribute to deciphering evolutionary morphology and developmental biology during early animal evolution. The preserved structures provide insights into tissue differentiation and body plan organization that hint at genetic and developmental pathways underpinning early metazoan diversification. This biological information, gleaned from fossils over half a billion years old, bridges paleontology and modern developmental biology, offering a rare glimpse into the origins of animal form and complexity.

With this discovery, the scientific community gains a vital window into one of the most enigmatic and transformative epochs in Earth’s history. The Tongshan Lagerstätte is not just a fossil site but a narrative archive chronicling the dawn of animal life’s complexity and ecological interaction. As research continues, this Lagerstätte promises to refine and evolve interpretations of early life and the evolutionary processes that have culminated in the rich biodiversity we witness today.

In conclusion, the Tongshan Lagerstätte from South China dramatically enriches our understanding of the terminal Ediacaran biome and offers new avenues for exploring the advent of complex animal ecosystems. Through exceptional preservation, advanced imaging, and interdisciplinary investigation, this site reveals a world teeming with evolutionary innovation just before the Cambrian explosion. This breakthrough transforms our comprehension of early animal evolution and underscores the delicate interplay of biology and environment in shaping the history of life on Earth.

Subject of Research: Terminal Ediacaran period fossils and ecosystem dynamics from the Tongshan Lagerstätte in South China.

Article Title: The terminal Ediacaran Tongshan Lagerstätte from South China.

Article References:
Hou, Jb., Wang, Xd., Hou, Zs. et al. The terminal Ediacaran Tongshan Lagerstätte from South China. Nat Commun 16, 10161 (2025). https://doi.org/10.1038/s41467-025-65176-2

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41467-025-65176-2

One organism, however, challenges this evolutionary orthodoxy: Salterella. Fossilized remains of this enigmatic creature are abundant in early Cambrian sediments and serve as crucial index fossils, enabling precise geological dating and stratigraphic correlation. Salterella’s architecture defies the conventional dichotomy by exhibiting both mineralized shell and internal mineralized lining, a combination scarcely observed elsewhere in the fossil record. This dual mineralization suggests a complex biological innovation, where a conical external shell encases the body, while the inner cavity is densely packed with selectively acquired minerals, creating a compact inner shell layer with unique structural properties.

The peculiar biological construct of Salterella has long perplexed paleontologists, complicating efforts to accurately place it within the tree of life. Initial classifications oscillated wildly—from molluscan relatives such as squids and octopuses to opisthobranchs akin to sea slugs, and even more distantly related groups like jellyfish and worms, reflecting the organism’s unusual morphology and uncertain affinities. By the 1970s, researchers responded to this taxonomic confusion by erecting a novel category encompassing Salterella alongside Volborthella, a similarly mystifying fossil exhibiting comparable shell structures. Yet, despite this taxonomic innovation, their evolutionary narratives remained disconnected, shrouded in mystery.

Prescott Vayda, a geosciences graduate student, embarked on a comprehensive investigation to decode Salterella’s biological and evolutionary significance. Collaborating with established experts including University Distinguished Professor Shuhai Xiao and colleagues from prestigious institutions like Johns Hopkins University, Dartmouth College, the University of Missouri, and the Denver Museum of Nature and Science, Vayda undertook an integrative approach. This involved meticulous field collection spanning diverse locales—from the arid basins of Death Valley and the frigid expanses of Yukon, Canada, to the richly fossiliferous rocks of Wythe County, Virginia. Advanced analytical methods probed Salterella’s morphology, mineralogical composition, and crystallographic features with unprecedented granularity.

Their findings revealed that Salterella’s mineral selection process was far from arbitrary. The organism demonstrated discernment, rejecting certain minerals such as clays while preferentially incorporating quartz and notably favoring titanium—a mineral prized for its exceptional durability and strength. This selective uptake implies sophisticated biological control mechanisms, possibly linked to enhancing shell robustness or fulfilling ecological functions like feeding stability. The researchers further inferred that Salterella must have possessed specialized appendages capable of mineral gathering, a biological complexity previously unrecognized.

Such mineralogical specificity and dual shell construction illuminate aspects of Salterella’s life history that had remained obscure. The internal mineral lining may have played critical roles in mechanical reinforcement or metabolic processes, while the conical outer shell provided environmental shielding. These discoveries not only reconstruct a more vivid image of Salterella’s biology but also inform broader evolutionary contexts regarding organismal strategies for skeletal development—a key facet of animal evolution.

Integrating evidence from shape analysis, ecological context, and detailed shell ultrastructure, the research consortium proposed a revised phylogenetic placement. Salterella and Volborthella exhibit traits aligning them with the Cnidaria—a diverse and ecologically vital phylum comprising modern corals, jellyfish, and sea anemones. This affiliation reorients our understanding of early animal evolution, indicating that complex mineralized skeletons may have evolved within cnidarians, or at least that their ancestors experimented with novel biomineralization strategies.

By restoring these fossil groups to their rightful phylogenetic context, the study bridges substantial gaps in evolutionary theory, suggesting that the origins of protective shells and internal skeletons are more intricate and varied than previously appreciated. The work underscores the evolutionary plasticity of biomineralization pathways, potentially informing biomimetic designs and shedding light on the adaptive pathways that shaped early metazoan diversification.

Vayda emphasizes the profound significance of this research beyond paleontological curiosities. “Understanding where we come from—tracing the intricate history of life on Earth—is both an amazing and beautiful pursuit,” he reflects. Such insights not only enrich scientific knowledge but also resonate with broader questions about life’s resilience and the evolutionary ingenuity that shaped the biological world.

The study published in the Journal of Paleontology marks a milestone in unraveling the complex evolutionary narrative of early skeletal animals. By situating Salterella and Volborthella within the cnidarian lineage, it challenges existing paradigms, prompts reevaluation of fossil classifications, and inspires fresh inquiries into Cambrian biodiversity and the genesis of biomineralization. As paleontologists continue to uncover and analyze these ancient life forms, the story of skeleton evolution gains new depth and texture, embodying the dynamic interplay between biology, geology, and chemistry that forged Earth’s primordial ecosystems.

In summary, this groundbreaking research illuminates Salterella’s unique dual mineralization strategy, its selective mineral incorporation—highlighting preferences for titanium—and reaffirmed phylogenetic placement within cnidarians. It transforms a puzzle fragment of the Cambrian fossil record into a vital key for understanding animal skeletal evolution, revealing an unexpected lineage linkage and providing a springboard for future exploration of early metazoan life.

Subject of Research: Evolution of mineralized skeletons and shells in early Cambrian organisms, specifically the biological and phylogenetic characterization of Salterella and Volborthella.

Article Title: A Cnidarian affinity for Salterella and Volborthella: implications for the evolution of shells

News Publication Date: 13-October-2025

Web References: https://doi.org/10.1017/jpa.2025.10164

Image Credits: Photo by Spencer Coppage for Virginia Tech.

Keywords: Paleontology, Fossils, Microfossils, Index fossils, Early Cambrian, Biomineralization, Cnidaria, Evolutionary biology, Skeleton evolution, Salterella, Volborthella, Mineral selection