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Late Devonian mass extinction

The Late Devonian mass extinction refers to a series of severe biotic crises that unfolded approximately 372 million years ago during the final stages of the Devonian Period, leading to the elimination of roughly 75% of marine species and profoundly altering global ecosystems.^[1] This event, one of the "Big Five" mass extinctions in Earth's history, primarily targeted marine invertebrates and reef-building organisms, including the collapse of extensive coral-stromatoporoid reef systems that had dominated shallow seas.^[2] Unlike singular catastrophic die-offs, it comprised multiple pulses over several million years, with the most intense occurring at the Frasnian-Famennian stage boundary around 372 million years ago.^[3] The extinction unfolded in at least two major episodes associated with the Kellwasser events: the Lower Kellwasser and Upper Kellwasser, spaced about 800,000 years apart, which drove widespread ocean anoxia and the demise of bottom-dwelling taxa such as brachiopods, trilobites, and ammonoids.^[1] A subsequent pulse, the Hangenberg event near the Devonian-Carboniferous boundary around 359 million years ago, further intensified losses, particularly among pelagic and nektonic organisms, resulting in over 50% decline in major vertebrate clades.^[2] These crises disrupted the marine carbon cycle, as evidenced by positive carbon isotope excursions up to 4‰, signaling perturbations from enhanced organic burial and eutrophication.^[3] Proposed causes include a confluence of environmental stressors, such as large-scale volcanism from events like the Viluy Traps, which released CO₂ and nutrients, exacerbating global warming and ocean deoxygenation.^[3] Concurrently, the rapid expansion of rooted land plants, including lycopsids and progymnosperms like Archaeopteris, increased terrestrial phosphorus export into oceans, fueling algal blooms and anoxic conditions through eutrophication—a process supported by elevated phosphorus-to-aluminum ratios in sedimentary records.^[3] Sea-level fluctuations and potential climate shifts, including cooling episodes, also contributed by restricting habitat connectivity and favoring mobile species over endemic, low-mobility groups like brachiopods.^[1] This mass extinction marked a pivotal transition, paving the way for the diversification of early tetrapods and modern marine ecosystems in the Carboniferous Period.^[2]

Paleoenvironmental and Biological Context

Late Devonian World

During the Late Devonian, Earth's landmasses were configured into two primary supercontinents: Gondwana in the southern hemisphere, comprising modern-day South America, Africa, India, Australia, and Antarctica, and Laurussia (also known as Euramerica) in the northern hemisphere, formed by the amalgamation of Laurentia and Baltica.^[4] These supercontinents were positioned near the equator in a tropical belt, separated by the expansive Rheic Ocean, which facilitated warm ocean currents but began narrowing due to the northward drift of Gondwana toward Laurussia.^[5] This configuration restricted global ocean circulation, particularly in epicontinental seas, leading to reduced ventilation in deeper waters and contributing to fluctuating sea levels through tectonic subsidence and eustatic changes. The climate of the Late Devonian was predominantly warm and humid, with equatorial temperatures supporting lush terrestrial ecosystems and extensive evaporation from shallow seas.^[6] Global sea levels were at one of their highest points in Earth history, resulting in vast shallow marine shelves and epicontinental seas that covered large portions of continental areas, creating expansive habitats for reef-building organisms.^[7] On land, the period marked the early development of widespread forests dominated by vascular plants such as Archaeopteris, which stabilized soils and began influencing weathering rates.^[8] Atmospheric CO₂ levels hovered around 2,000–2,100 ppm, sustaining the greenhouse conditions while beginning a gradual decline due to enhanced silicate weathering by these emerging forests.^[9] Oceanic conditions featured precursors to widespread anoxia, including stratified water columns in restricted basins and increased nutrient inputs from terrestrial sources, which promoted algal blooms and organic matter burial.^[10] Nutrient cycling was intensified by the proliferation of land plants, leading to higher phosphorus and nitrogen fluxes into coastal waters via enhanced runoff and weathering, thereby exacerbating eutrophication in shallow shelves.^[3] These dynamics set the stage for episodic oxygen depletion, particularly in epicontinental seas where circulation was limited by the supercontinent geometry.^[11] A major geological event was the ongoing Appalachian-Caledonian (Acadian) orogeny, driven by the collision of Avalonian continental fragments with Laurussia along their eastern margins, which uplifted mountain chains and increased sediment supply to adjacent basins.^[12] This orogeny resulted in massive clastic sedimentation, exemplified by the thick Catskill Delta wedge in eastern North America, where rivers transported vast quantities of eroded material westward, burying shallow marine environments and altering depositional patterns.^[13] The tectonic activity also contributed to regional sea-level variations through foreland basin formation and isostatic adjustments.^[14]

Pre-Extinction Biodiversity

The Late Devonian Period, spanning approximately 382 to 359 million years ago, was characterized by a peak in marine biodiversity, with over 1,000 genera of marine invertebrates documented in the fossil record prior to the onset of major biotic turnover.^[15] This high diversity was supported by expansive shallow marine environments that fostered complex ecosystems, including vast reef systems constructed primarily by stromatoporoids and rugose and tabulate corals.^[16] Stromatoporoids, encrusting sponge-like organisms, formed the structural framework of these reefs, often in association with branching and massive corals that created biodiverse habitats for associated fauna. Benthic communities thrived on and around these structures, dominated by articulate brachiopods such as spiriferids, which occupied a wide array of ecological niches from epifaunal suspension feeders to infaunal burrowers, alongside persistent trilobites and emerging ammonoids that marked the diversification of cephalopods.^[16] Vertebrate diversity also flourished in these marine settings, with jawed fishes achieving prominence as nektonic predators. Placoderms, armored fishes with diverse morphologies ranging from bottom-dwelling forms to active swimmers, represented one of the most speciose groups, occupying predatory and durophagous roles across both marine and freshwater habitats.^[17] Sarcopterygians, including early lobe-finned fishes like those ancestral to tetrapods, underwent significant radiation, adapting to a variety of aquatic environments and contributing to the increasing complexity of food webs through their versatile feeding strategies.^[16] These nektonic predators, alongside ammonoids and early sharks, exerted top-down controls on lower trophic levels, enhancing the ecological dynamism of open-water and reef-margin communities. On land, terrestrial ecosystems were undergoing rapid advancement, driven by the proliferation of early vascular plants that formed the first widespread forests. Progymnosperms, such as the tree-like Archaeopteris, dominated these landscapes with their woody trunks, fern-like foliage, and spore-based reproduction, reaching heights of up to 30 meters and stabilizing soils through extensive root systems.^[16] Precursors to seed plants, including early pteridosperms or seed ferns, began appearing in the latest Devonian, representing a transitional phase toward more efficient reproductive strategies. Arthropod colonization paralleled this vegetal expansion, with myriapods, arachnids, and primitive hexapods exploiting detrital and herbivorous niches in the understory and litter layers, marking the initial establishment of terrestrial food chains.^[18] These developments were enabled by the period's warm, humid climates and nutrient-rich continental settings, which promoted both marine and terrestrial biotic richness.^[16]

Event Chronology

Timing and Pulses

The Late Devonian mass extinction unfolded across the Frasnian-Famennian boundary, spanning approximately 372 to 359 million years ago (Ma), with the primary phases concentrated in distinct pulses that punctuated this interval. The main events include the Kellwasser pulses near 372 Ma and the Hangenberg event around 359 Ma, marking a series of abrupt crises rather than a singular catastrophe. These phases are recognized globally through stratigraphic signatures of anoxic black shales and faunal turnovers, reflecting episodic environmental stress on marine ecosystems.^[19]^[20]^[21] The Kellwasser events comprise two closely spaced pulses: the Lower Kellwasser event, followed shortly by the Upper Kellwasser event, both interpreted as brief oceanic perturbations involving widespread anoxia and dysaerobic conditions lasting on the order of tens of thousands of years. These occurred within the latest Frasnian stage, with the Lower event initiating the crisis sequence and the Upper event coinciding with the boundary proper, leading to significant biotic losses among reef-builders and pelagic organisms. The Hangenberg event, a separate crisis in the earliest Famennian, represents another sharp pulse of environmental instability, characterized by a thin black shale layer and a renewed spike in extinction intensity near the Devonian-Carboniferous transition.^[19]^[22]^[23] High-precision U-Pb zircon geochronology has refined the temporal framework of these pulses, placing the Frasnian-Famennian boundary at 371.87 ± 0.11 Ma, with the Kellwasser events anchored immediately preceding this date. For the Hangenberg event, U-Pb dating constrains it to approximately 358.9 Ma globally (e.g., 358.97 ± 0.11 Ma to 358.89 ± 0.20 Ma in key sections), highlighting its position as a terminal Devonian perturbation roughly 13 million years after the Kellwasser sequence. These absolute ages integrate with cyclostratigraphic records from sedimentary cycles in key sections, revealing that the pulses were modulated by orbital forcing, particularly obliquity-paced variations of about 100 kyr under low-eccentricity orbits, as evidenced in studies from 2017 and 2020 that link astronomical cycles to anoxic horizon deposition durations of ~90-110 kyr for the Kellwasser events.^[19]^[23]^[22]^[19] Global correlation of the extinction pulses relies on biostratigraphic frameworks, particularly conodont zonations that track faunal shifts across the events. The Kellwasser events align with the Palmatolepis rhenana Zone in the Frasnian, while the Frasnian-Famennian boundary is defined by the Palmatolepis-Ulmia transition, marked by the near-total extinction of Palmatolepis species and the emergence of Ulmia in the lowermost Famennian Crepida Zone. The Hangenberg event corresponds to the upper Siphonodella Zone, providing a consistent marker for synchronizing sections worldwide through these microfossil assemblages.^[24]^[21]

Duration and Stratigraphic Markers

The Late Devonian mass extinction extended over an approximately 13-million-year interval, spanning from around 372 million years ago (Ma) during the late Frasnian to 359 Ma at the end of the Famennian, marked by multiple punctuated crises rather than a uniform decline. The primary phase of intense biotic turnover occurred over 1–2 million years centered on the Frasnian-Famennian (F/F) boundary at approximately 372 Ma, encompassing the two major Kellwasser events that drove significant marine anoxia and biodiversity loss. This prolonged timeframe reflects a series of ecological perturbations, with shorter, high-intensity pulses embedded within a broader backdrop of environmental instability.^[2]^[22]^[25] Key stratigraphic markers defining this interval include the Kellwasser horizons, prominent organic-rich black shales that signal episodes of widespread oceanic anoxia and represent the primary lithological indicators of the main extinction pulses. These horizons, particularly the Lower and Upper Kellwasser events, are richly documented in type localities across Europe, such as the Kellwasser-Tal section in Germany's Upper Harz Mountains, where they overlie and underlie conodont-defined biostratigraphic zones like the linguiformis and triangularis. Conodont biofacies shifts provide additional biostratigraphic precision, transitioning from diverse, warm-water assemblages dominated by palmatolepid genera in the pre-extinction Frasnian to low-diversity, stress-tolerant forms in the post-boundary Famennian, reflecting ecological collapse and habitat restriction. Iridium anomalies, though not ubiquitous, have been identified in select sections, such as the Canning Basin in Western Australia, where elevated levels near the F/F boundary coincide with stromatolitic beds and suggest localized extraterrestrial influence or enhanced sedimentation, albeit without conclusive global impact evidence.^[26]^[27]^[22]^[28] Recent terrestrial records enhance global correlation, including a 2025 study from an expanded section in East Greenland that documents mercury spikes at 371 Ma, aligning with the F/F boundary crises and indicating volcanic or atmospheric perturbations extending to continental environments. These spikes, preserved in paleosols and coal measures, corroborate marine signals from European and Appalachian sections, broadening the stratigraphic framework beyond oceanic basins. However, uncertainties persist regarding the precise synchrony of these markers across continents, stemming from regional facies variations—such as deeper-water anoxic shales in Europe versus shallower, more oxygenated deposits in Laurentia—that complicate direct correlations and highlight the need for integrated chemo- and biostratigraphy.^[29]^[30]^[22]

Extinction Patterns

Reef Ecosystems

Prior to the Late Devonian mass extinction, reef ecosystems were dominated by frameworks constructed primarily by stromatoporoid sponges and tabulate and rugose corals, which formed expansive, complex structures in shallow tropical marine environments.^[31] These frameworks supported diverse ecological communities, including symbiotic algae within the coral tissues that enhanced calcification and growth, as well as a variety of herbivores such as brachiopods, crinoids, and early gastropods that grazed on algal mats and encrusting organisms.^[32] This biodiversity peaked during the Frasnian stage, with reefs serving as hotspots for metazoan innovation and habitat provision across equatorial regions.^[33] The extinction pulses, particularly the Kellwasser events at the Frasnian-Famennian boundary, inflicted severe damage on these reef systems, resulting in the near-total collapse of metazoan-dominated frameworks, with over 80% loss of stromatoporoid genera by the end of the Devonian.^[34] Stromatoporoids, which comprised the bulk of reef volume, suffered severe extinction, while coral diversity dropped by more than 50% during the Late Devonian crises, leading to the dominance of microbialites—stromatolite-like structures built by cyanobacteria and algae—in post-extinction Famennian reefs.^[34] This shift marked a fundamental reorganization, with microbial communities filling the vacated ecological niche of primary framework builders for millions of years.^[31] Survival patterns among reef organisms showed marked variation by water depth and geography; shallow-water, warm-adapted builders in tropical shelves experienced the highest mortality due to anoxia and thermal stress, whereas deeper-water (>100 m) coral genera exhibited higher resilience compared to those in euphotic zones. Regionally, reefs in southern high-latitude settings, such as parts of Gondwana, displayed greater resistance, likely due to cooler waters and reduced anoxic incursions, allowing limited survival of stromatoporoid lineages into the early Carboniferous.^[34] The ecological fallout from this reef collapse was profound, as the loss of three-dimensional habitat complexity diminished niches for associated fauna, contributing to broader declines in marine invertebrate diversity by disrupting food webs and shelter availability.^[35] This habitat degradation amplified extinction pressures on non-reef invertebrates, underscoring the reefs' role as foundational ecosystems.^[36]

Marine Invertebrates

The Late Devonian mass extinction profoundly affected non-reef marine invertebrate phyla, leading to substantial declines in diversity across several key groups. Overall, marine invertebrate generic diversity dropped from approximately 700 to around 400 genera in major phyla, reflecting a loss of about 40-50% at the genus level during the Frasnian-Famennian transition.^[2]^[34] Brachiopods experienced significant losses, with roughly 75% of genera disappearing during the Frasnian stage, particularly during the Kellwasser event, though some lineages recovered partially in the Famennian; a 2023 study estimates ~50% species loss among Appalachian brachiopods during the Lower Kellwasser, with survivors exhibiting niche conservatism.^[34]^[37] Trilobites suffered even more severely, with significant losses during the Kellwasser crisis, reducing family diversity from 13 in the Givetian to just 1 by the end of the Devonian, and only 8 genera surviving into the Famennian; offshore, specialized epi- and endobenthic forms were preferentially impacted.^[38] Ammonoids underwent high turnover, with an estimated 88% species extinction across the event, though a few deeper-water genera persisted through the Kellwasser and diversified in the Famennian before further losses at the Hangenberg event.^[34] Ostracods also faced heavy attrition during the Kellwasser event, with global species extinction rates around 80% and genus losses of 14-26% depending on suborder; renewal rates were high, indicating rapid but selective replacement.^[39] This event showed clear selectivity, favoring the survival of smaller, deeper-water forms over larger, shallow-water ones, as well as planktonic over benthic taxa, with low-oxygen tolerant genera faring better overall.^[39]^[34] Extinction patterns varied regionally, with higher losses documented in epicontinental seas compared to open-ocean settings, where sea-level fluctuations and restricted circulation amplified environmental stress on benthic communities.^[40] In contrast, some isolated deeper-water populations, including certain ostracod and ammonoid lineages, exhibited greater resilience.^[39]

Vertebrates and Other Groups

The Late Devonian mass extinction profoundly affected early vertebrates, with the Hangenberg event causing acute and systematic losses across major jawed fish clades, including over 50% declines in diversity for groups such as placoderms, acanthodians, and sarcopterygians.^[2] Placoderms, the armored jawed fishes that dominated Devonian seas, experienced particularly severe impacts, with approximately 44% of high-level vertebrate clades lost overall and minimal recovery for placoderm lineages thereafter.^[2] This decline primarily targeted diverse arthrodire placoderms, reflecting disruptions in marine ecosystems without clear selectivity favoring body size or habitat.^[2] In contrast, certain sarcopterygian (lobe-finned) fishes survived the crisis, albeit with over 50% diversity loss, setting the stage for the subsequent radiation of tetrapodomorphs and the transition to land-dwelling vertebrates.^[2] Acanthodians, often considered "spiny sharks," also faced substantial losses exceeding 50% but demonstrated resilience through the persistence of relict genera into the late Paleozoic, highlighting predator-prey dynamics where heavily armored forms like placoderms declined more sharply than less defended groups.^[2] These patterns underscore an ecosystem restructuring, with survivors including early actinopterygians and chondrichthyans eventually dominating post-extinction fish assemblages.^[2] Beyond marine vertebrates, the extinction exerted minor but notable effects on terrestrial and freshwater groups. Nonmarine faunas, including freshwater fish communities, underwent significant turnover comparable to marine impacts, with no evident refugia in inland waters.^[2] Early land plants faced a "floral crisis," marked by biodiversity losses and disruptions linked to environmental perturbations, though vascular plant diversification continued overall.^[41] Arthropods on land, such as early insects and myriapods, experienced limited direct effects, with terrestrial ecosystems remaining relatively buffered compared to oceanic realms.^[42] Recent geochemical analyses, including stable carbon isotope excursions, reveal that fish community shifts during the extinction pulses were closely tied to widespread marine anoxia, which expanded rapidly at the onset of the Hangenberg Crisis and contributed to vertebrate mortality.^[43]

Overall Diversity Decline

The Late Devonian mass extinction led to substantial biodiversity loss, with estimates indicating approximately 75% of marine species were eliminated across its multiple pulses.^[1]^[44] This event particularly devastated marine ecosystems, where standing diversity was roughly halved by the end of the Frasnian stage due to successive declines.^[45] At higher taxonomic levels, marine genus extinction rates averaged around 20% per major pulse, such as the Kellwasser and Hangenberg events, contributing to an overall loss of about 50% of genera.^[2] Family-level losses are more debated, ranging from 19% to 50%, largely because of the Lazarus effect—where taxa temporarily vanish from the fossil record due to habitat shifts or sampling gaps, inflating apparent extinction intensities. Compared to the other "Big Five" mass extinctions, the Late Devonian event ranks among the largest in terms of species-level impact (~75% loss), trailing the end-Permian (~96%) and end-Ordovician (~85%) but comparable to the end-Triassic (~80%) and end-Cretaceous (~76%).^[45]^[46] Unlike the more indiscriminate end-Cretaceous extinction, the Devonian crisis was highly selective, disproportionately affecting warm-water, tropical shelf communities and reef-building organisms while sparing many deep-water and high-latitude taxa.^[47] This selectivity is evident in the collapse of diverse benthic assemblages, where ecological roles in shallow marine environments were severely disrupted.^[37] Recent analyses, including 2023 studies leveraging enhanced fossil sampling from understudied regions, have refined these metrics and revealed that invertebrate losses—particularly among brachiopods and ostracods—were likely underestimated in earlier assessments, with genus-level declines reaching up to 35-50% when accounting for improved stratigraphic resolution.^[37]^[39] These updates underscore the event's role as a prolonged biodiversity bottleneck rather than a singular catastrophe, emphasizing the interplay of biotic and environmental factors in driving global marine diversity decline.^[48]

Hypothesized Causes

Climatic and Oceanic Shifts

The Late Devonian mass extinction was associated with significant global cooling, as evidenced by oxygen isotope analyses of conodont apatite, which indicate a temperature drop of approximately 5–7°C during the Frasnian-Famennian boundary interval.^[49] This cooling is inferred from an increase in δ¹⁸O values by up to 2.5‰ in mono-specific conodont samples from South China and Europe, reflecting a shift toward cooler seawater temperatures that stressed marine ecosystems.^[49] Such cooling may have been driven by enhanced silicate weathering on land, which drew down atmospheric CO₂ and promoted glaciation, though the exact mechanisms remain debated.^[1] Oceanic anoxia expanded markedly during the extinction pulses, with the development of widespread oxygen minimum zones that restricted habitable seafloor areas for benthic organisms.^[50] Black shale deposits, rich in organic carbon and trace metals like molybdenum and uranium, serve as key proxies for these anoxic conditions, recording episodes of euxinia (sulfide-rich waters) in epicontinental seas and deeper ocean basins.^[51] For instance, the Kellwasser and Hangenberg events are marked by thick black shales in regions such as the Appalachian Basin and South China, indicating intensified deoxygenation that contributed to the collapse of reef communities and invertebrate diversity.^[52] This anoxia was likely exacerbated by nutrient influxes and sluggish ocean circulation, leading to stratified water columns.^[50] Sea-level fluctuations played a critical role, with major regressions coinciding with extinction pulses that exposed continental shelves and reduced shallow marine habitats.^[53] These regressions, driven by eustatic controls possibly linked to tectonic and climatic factors, followed rapid transgressions and resulted in habitat loss for shelf-dwelling species during the Lower and Upper Kellwasser events. In the Appalachian region, such regressions are documented in stratigraphic records showing erosional unconformities and condensed sections, amplifying biotic stress through shoreline migration and increased sedimentation.^[54] Recent research underscores climate as a primary driver in the Appalachian Basin, where 2022 analyses of fossil assemblages and geochemical proxies confirm that cooling and associated environmental perturbations were more influential than volcanism in triggering local extinctions.^[1] A 2023 study highlights ongoing debate regarding the balance between sustained global cooling and transient warming episodes, with conodont isotope data supporting cooling as the dominant signal amid an overall Late Devonian warming trend.^[3] These findings suggest that while volcanism may have initiated some perturbations, climatic shifts were central to the extinction dynamics.^[55]

Biotic and Terrestrial Influences

The expansion of land plants during the Late Devonian, particularly the development of extensive rooting systems around 372 million years ago, significantly altered terrestrial nutrient dynamics and contributed to marine ecosystem stress. These rooting structures enhanced soil penetration and chemical weathering, leading to increased release of phosphorus from continental rocks into river systems. This process, as modeled in a 2023 study, could have driven widespread eutrophication in marine environments, promoting algal blooms that depleted oxygen levels and exacerbated anoxia, particularly during the Kellwasser event.^[3] Enhanced nutrient cycling from early forests amplified the flux of phosphorus via rivers to coastal and open ocean settings, fostering conditions for organic matter proliferation and subsequent oxygen drawdown. The burial of this organic carbon further intensified hypoxia in stratified marine waters, linking terrestrial biotic innovations directly to pulsed extinction events in reef and benthic communities. Such mechanisms highlight how the proliferation of vascular plants transformed global biogeochemical cycles, with riverine phosphorus export potentially increasing by factors sufficient to sustain anoxic episodes across epicontinental seas.^[3] Terrestrial sedimentary records provide direct evidence of these biotic influences, as seen in a highly expanded section from East Greenland spanning the Late Devonian mass extinction interval around 371 million years ago. This 2025 analysis reveals correlations between the spread of land plants, elevated mercury concentrations indicative of environmental stress, and fluctuations in atmospheric CO₂ levels, underscoring the role of vegetation in modulating climate and nutrient delivery. Plant fossils in these strata show progressive diversification, aligning with geochemical signatures of heightened weathering.^[29] Feedback loops involving early forests further propagated cooling trends, as increased silicate weathering by plant roots accelerated atmospheric CO₂ drawdown, amplifying global temperature declines and potentially contributing to brief glacial episodes. This carbon sequestration, coupled with organic matter burial, created a self-reinforcing cycle that lowered sea levels and intensified marine anoxia through reduced ocean circulation. These terrestrial-driven changes set the stage for long-term Earth system reconfiguration during the extinction.^[29]^[56]

Geological and Extraterrestrial Factors

The Viluy Traps, a large igneous province in eastern Siberia, erupted around 370 million years ago during the Late Devonian period, coinciding with major extinction pulses such as the Kellwasser and Hangenberg events.^[57] These eruptions released vast quantities of sulfur dioxide (SO₂) into the atmosphere, which could have induced short-term global cooling by forming sulfate aerosols that reflected sunlight, alongside longer-term warming from CO₂ emissions.^[58] Geochemical evidence includes widespread mercury (Hg) anomalies in sedimentary records across multiple continents, serving as proxies for intense volcanic activity, with Hg/TOC ratios indicating atmospheric deposition from large igneous province (LIP) emissions.^[59] This volcanism may have contributed to oceanic anoxia through nutrient runoff and thermal stratification, exacerbating marine extinctions.^[59] The impact hypothesis centers on the Siljan crater in Sweden, dated to approximately 381 million years ago via ⁴⁰Ar/³⁹Ar laser dating of melt breccias, placing it near the Frasnian stage of the Late Devonian.^[60] Proponents cite microtektite-like glass spherules and shocked minerals in Belgian sections as evidence linking an extraterrestrial impact to the Frasnian-Famennian boundary crisis around 372 million years ago, potentially triggering tsunamis, wildfires, and atmospheric dust loading that disrupted photosynthesis.^[61] However, the hypothesis remains debated due to the crater's age slightly predating the main extinction pulses and the absence of a widespread iridium anomaly, a hallmark of other impact-related extinctions like the Cretaceous-Paleogene event; localized iridium spikes exist but lack global consistency.^[62] Tectonic processes, particularly orogenic uplift, played a role in altering Late Devonian environments by accelerating continental weathering rates.^[63] Uplift events, such as those associated with the Acadian orogeny in Laurentia, exposed fresh rock surfaces to erosion, enhancing chemical weathering and releasing nutrients like phosphorus into rivers and oceans, which promoted eutrophication and anoxic conditions.^[64] Osmium isotope (¹⁸⁷Os/¹⁸⁸Os) data from black shales show negative excursions synchronous with extinction horizons, confirming pulses of intensified weathering around 372 and 359 million years ago, driven by tectonic reconfiguration rather than solely biotic factors.^[64] This uplift also contributed to sea-level fluctuations, stressing shallow-marine habitats.^[63] Extraterrestrial influences beyond impacts include the proposed supernova or gamma-ray burst (GRB) hypothesis, suggesting a stellar explosion around 360 million years ago at a distance of about 20 parsecs could have depleted stratospheric ozone via cosmic rays, increasing ultraviolet radiation and harming planktonic life.^[65] Evidence includes elevated ⁶⁰Fe isotopes in sediments, interpreted as fallout from nearby nucleosynthesis, correlating with the Hangenberg extinction.^[65] However, this theory lacks direct confirmation, such as unambiguous GRB signatures, and recent modeling indicates Earth's atmosphere largely attenuates gamma rays, limiting biosphere damage from short bursts to minor ozone loss without widespread extinction-scale effects.^[66] Post-2020 critiques emphasize the rarity of nearby supernovae and the need for multiple events to explain pulsed extinctions, rendering the mechanism speculative.^[66] A March 2025 study further explores this hypothesis, suggesting that violent supernovae could have triggered the Late Devonian extinction along with the Ordovician one through ozone depletion and cosmic ray effects.^[67]

Recovery and Long-Term Impacts

Immediate Biotic Turnover

Following the Late Devonian mass extinction events, particularly the Hangenberg crisis around 359 million years ago, marine ecosystems underwent rapid restructuring characterized by the dominance of opportunistic survivor taxa and a shift toward simpler community structures. Complex food webs, reliant on reef-building metazoans such as stromatoporoids and rugose corals, collapsed due to the loss of primary producers and predators, leading to reduced trophic complexity and increased vulnerability to secondary extinctions in interconnected networks.^[68] This breakdown favored deposit-feeding organisms over suspension feeders, as anoxic conditions and nutrient perturbations disproportionately affected filter-feeding guilds, resulting in a proliferation of detritivores that exploited organic detritus in depauperate seafloors.^[69] Among the key survivors were opportunistic "disaster taxa" that rapidly repopulated disturbed habitats. The brachiopod Ambocoelia gregaria exemplified this, maintaining high abundance in storm-influenced, nearshore environments through niche conservatism along depth and disturbance gradients, even as overall species richness remained low.^[37] Certain conodont lineages, such as those in the genus Icriodus, persisted as resilient opportunists in shallow-water settings, avoiding the severe losses that decimated deeper-water palmatolepid forms during the Kellwasser and Hangenberg pulses.^[70] Ostracods also showed notable repopulation, with renewal rates reaching 62% post-Hangenberg in South China, driven by diversification possibly from psychrospheric refugia that buffered against global anoxia.^[71]^[72]^[73] A prominent ecological shift was the resurgence of microbial carbonates, which filled niches vacated by skeletal reef builders. Following the Hangenberg extinction, microbialites proliferated globally within 100–300 thousand years, forming low-diversity mounds and coatings across paleolatitudes from 40° north to south of the equator, facilitated by elevated seawater calcite saturation and reduced metazoan grazing.^[74] These structures supported pioneer communities of deposit feeders and encrusters, marking an initial phase of biotic stabilization amid persistent environmental stress. The timescale of immediate biotic turnover was relatively swift for opportunistic colonization but protracted for full community reorganization. Initial recovery signals, including microbial dominance and survivor blooms, emerged within 1–2 million years after the Hangenberg event, as evidenced by renewed ostracod and brachiopod assemblages in Appalachian and Eurasian sections.^[75] However, complete ecological turnover, involving the reestablishment of diverse trophic levels, extended over approximately 10 million years into the Early Carboniferous, reflecting lingering effects of anoxia and habitat fragmentation.^[2]

Evolutionary Consequences

The Late Devonian mass extinction profoundly reshaped vertebrate evolution by creating ecological vacancies that enabled the radiation of surviving lineages. The near-total extinction of placoderms, which comprised a dominant component of Devonian fish faunas, eliminated key predators and competitors, paving the way for the diversification of actinopterygians (ray-finned fishes) and chondrichthyans (cartilaginous fishes) in the Carboniferous.^[2] This bottleneck event resulted in long-term losses exceeding 50% of diversity across major jawed vertebrate clades, fundamentally altering the trajectory of aquatic vertebrate evolution.^[76] Similarly, the survival of sarcopterygian fishes, precursors to tetrapods, through the Hangenberg crisis allowed these groups to persist in low-diversity refugia, setting the stage for their transition to terrestrial environments during the early Carboniferous.^[2] These shifts contributed to simplified marine ecosystems persisting into the Carboniferous, characterized by reduced reef complexity and dominance of opportunistic taxa following the collapse of stromatoporoid- and coral-dominated structures.^[77] Full biotic recovery, including the re-establishment of diverse metazoan reefs and overall marine diversity, took approximately 30 million years, with Mississippian faunas exhibiting lower trophic complexity compared to pre-extinction Devonian assemblages.^[77] The extinction's legacies extended to broader phylogenetic patterns, as the rise of modern fish groups like actinopterygians laid foundational diversity for subsequent Mesozoic marine innovations, including enhanced durophagy and predation dynamics.^[47] Recent research highlights accelerated evolutionary rates in post-extinction survivors. For instance, a 2022 analysis of Late Devonian actinopterygian fossils revealed high lineage survivorship across the Hangenberg event, with diversification pulses decoupled from the extinction itself, indicating rapid adaptive radiations in ray-finned fishes.^[78] In invertebrates, 2023 studies on brachiopods demonstrate niche conservatism amid ecological upheaval, yet with evidence of accelerated morphological evolution in surviving genera, underscoring the extinction's role in spurring innovation under stress.^[79] These patterns parallel modern risks, where expanding land plant nutrient inputs may exacerbate ocean anoxia, mirroring Devonian feedbacks that drove the crisis.^[3]

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Changes in the hydrologic cycle and pedogenic weathering processes as a consequence of the Middle-to-Late Devon- ian spread of vascular land plants (see text ...
[9]
The climate change caused by the land plant invasion in the Devonian
From the Early to the Late Devonian, our model simulates a significant atmospheric CO2 drop from 6300 to 2100 ppmv that is due to an increase in the consumption ...Missing: scholarly | Show results with:scholarly
[10]
Lipid biomarker stratigraphic records through the Late Devonian ...
The pervasiveness of black shale preservation in association with Late Devonian biological crises suggests marine anoxia played a major role in driving ...
[11]
Exploring the mechanisms of Devonian oceanic anoxia - CP
Jan 28, 2025 · Our results indicate that continental configuration is crucial for Devonian ocean anoxia, significantly influencing ocean circulation and oxygen levels.Missing: precursors | Show results with:precursors
[12]
[PDF] Paleozoic Evolution of the Appalachians: Tectonic Overview
Cause(s)?. • Late Devonian glaciation in Gondwana possible climatic feedbacks: spread of forests, burial of carbon, lowering of.
[13]
The Appalachian orogen: A brief summary - GeoScienceWorld
Sep 1, 2010 · The Appalachians are a Paleozoic orogen that formed in a complete Wilson cycle along the eastern Laurentian margin following the breakup of supercontinent ...
[14]
Late Devonian syntaxis in the Northern Appalachian orogen
The Late Devonian formation of a syntaxis in the Central Appalachians was proposed by Broussard et al. (2018) to explain the rapid uplift, erosion and ...
[15]
[PDF] Origination, extinction, and mass depletions of marine diversity
Diversity and diversity turnover of marine genera by interval through the Phanerozoic. ... and Late Devonian diversity depletions, is manifest in the Late ...
[16]
The Devonian Period
The Devonian seas were dominated by brachiopods, such as the spiriferids, and by tabulate and rugose corals, which built large reefs in shallow waters.Missing: pre- biodiversity
[17]
Placoderms (Armored Fish): Dominant Vertebrates of the Devonian ...
Placoderms, the most diverse group of Devonian fishes, were globally dis- tributed in all habitable freshwater and marine environments, like teleost fishes ...
[18]
The first terrestrial ecosystems - Encyclopedia of the Environment
May 1, 2025 · Arthropods were the first animals to take the first steps on land along with myriapods (“centipedes”) and arachnids (spiders, scorpions, mites) ...Missing: ferns | Show results with:ferns
[19]
Anchoring the Late Devonian mass extinction in absolute time by ...
Jul 31, 2020 · This time was characterized by two pulses of oceanic anoxia, named the Lower and Upper Kellwasser events, during which massive marine ...
[20]
Precisely dating the Frasnian–Famennian boundary - Nature
Jun 22, 2018 · A new age of 372.36 ± 0.053 Ma is determined for this bentonite, confirming a date no older than 372.4 Ma for the Frasnian–Famennian boundary.
[21]
The global Hangenberg Crisis (Devonian–Carboniferous transition)
The global Hangenberg Crisis near the Devonian–Carboniferous boundary (DCB) represents a mass extinction that is of the same scale as the so-called 'Big Five' ...<|control11|><|separator|>
[22]
Timing and pacing of the Late Devonian mass extinction event ...
Dec 22, 2017 · In this study we present a global orbitally calibrated chronology across this momentous interval, applying cyclostratigraphic techniques.
[23]
Geochronological constraints on the Hangenberg Event of the latest ...
May 15, 2024 · The Hangenberg Event occurred at 360.47 ± 0.68 Ma in the Daposhang section. •. New age for Devonian–Carboniferous boundary overlaps with that in ...
[24]
GSSP for Famennian Stage
The boundary corresponds to the extinction of all species of the conodonts Ancyrodella and Ozarkodina and the loss of all but a few species of Palmatolepis, ...Missing: Ulmia transition
[25]
Global iridium anomaly, mass extinction, and redox change at the ...
Jun 2, 2017 · Late Devonian “Kellwasser Event” mass-extinction horizon in Germany: No geochemical evidence for a large-body impact. Geology. Tempo of the ...
[26]
Event-stratigraphic markers within the Kellwasser crisis near the ...
Short time intervals of anomalous conditions, often referred to as “global events”, yield excellent tools for detailed stratigraphic correlations.
[27]
The type locality of the Kellwasser-Horizons in the Upper Harz ...
Aug 17, 2025 · The stratigraphic section "Kellwasser-Tal" is the type locality of the Late Devonian Kellwasser Horizons. The locality, which was already ...
[28]
Iridium Anomaly in the Upper Devonian of the Canning Basin ...
It occurs at or near the Frasnian-Famennian boundary, which is known to be associated with a major mass-extinction event of global extent.
[29]
Terrestrial palaeoclimate, mercury, atmospheric CO 2 and land ...
Jul 14, 2025 · Here we report the first terrestrial section of the Late Devonian mass extinction (371 million years ago) from a highly expanded section in East Greenland.
[30]
Terrestrial palaeoclimate, mercury, atmospheric CO 2 and land ...
There is an unexplained terrestrial mass extinction at the Devonian-Carboniferous boundary (359 million years ago). The discovery in east Greenland of malformed ...
[31]
How microbes replaced metazoans in reef ecosystem during the ...
Oct 24, 2025 · The Late Devonian mass extinction exerted a negative influence in both the neritic and pelagic ecosystems, and Frasnian coral-stromatoporoid ...
[32]
Coral photosymbiosis on Mid-Devonian reefs - PMC - PubMed Central
It has been suggested that the ability to host photosymbionts was paramount to the ecological success of ancient reef communities during the Givetian stage and ...
[33]
100 Million Years of Reef Prosperity and Collapse: Ordovician to ...
Jul 21, 2017 · Near the end of the Middle Devonian (mid- to late Givetian), the primary reef dwellers declined sharply in diversity, marked generally by ...<|control11|><|separator|>
[34]
reef recovery following the frasnian–famennian (late devonian ...
Oct 1, 2011 · In contrast to other prominent mass extinctions, the Late Devonian biotic crisis is characterized by three peaks in extinction intensity, ...
[35]
Late Devonian - an overview | ScienceDirect Topics
The Late Devonian was a time of two substantial extinctions of marine animals, at the Frasnian-Fammenian boundary (“Kellwasser event”) and/or at the end of the ...
[36]
Functional consequences of Palaeozoic reef collapse - Nature
Jan 26, 2022 · Our results suggest that the collapse of the huge Devonian reef systems was correlated with a breakdown of photosymbiosis and extinction of photosymbiotic ...
[37]
(PDF) The late Devonian trilobite crises - ResearchGate
Aug 6, 2025 · After a phase of adaptive radiation, off‐shore trilobite communities were severely affected during the mid‐ and end‐Late Devonian crises.Missing: invertebrates | Show results with:invertebrates
[38]
Marine ostracod faunas through the Late Devonian extinction events ...
Few new species belong to poorly diversified genera such as Aechmina Jones & Holl, 1869, Rectella Neckaja, 1958 and Reticestus Kesling and Kilgore, 1952 ( ...Missing: compendium | Show results with:compendium<|separator|>
[39]
Paleontologists find extinction rates higher in open-ocean settings ...
Nov 20, 2009 · For one thing, because they were so broad and relatively flat, drops in sea level should have had more drastic effects on epicontinental seas ...
[40]
Late Devonian Mass Extinction - McGhee - Wiley Online Library
Nov 15, 2012 · The Late Devonian mass extinction, one of the 'Big Five', occurred 374.5 Ma, causing severe biodiversity loss, impacting early vertebrates and ...
[41]
Devonian Period—419.2 to 358.9 MYA (U.S. National Park Service)
Apr 28, 2023 · The Devonian ended with a mass extinction, during which 22% of all marine families disappeared. Little is known about the extinction of land ...<|control11|><|separator|>
[42]
"Extensive marine anoxia associated with the Late Devonian ...
Mar 1, 2020 · The rapid expansion of marine anoxia coincident with the onset of the Hangenberg Crisis supports marine anoxia as an important kill mechanism.
[43]
On the causes of mass extinctions - ScienceDirect.com
The key features of the extinction are losses of around 75% of species ... (Late Devonian) mass extinction in Poland, Germany, Austria and France. Geol ...
[44]
Forty years later: The status of the “Big Five” mass extinctions
Jan 5, 2023 · Magnitude. But in terms of magnitude, the loss of species to date compared with the species loss in the fossil record is very small. So, does ...
[45]
Estimates of the magnitudes of major marine mass extinctions in ...
Oct 3, 2016 · ... marine genera (B). Included intervals range from the late ... Late Devonian (Frasnian), Late Permian (Changhsingian), Late Triassic ...
[46]
Selectivity and the effect of mass extinctions on disparity ... - Science
May 5, 2021 · ... genera lost) and the Late Devonian extinction (69.2% of genera lost). We then generated an extinction space by running a principal ...Results · Discussion · Materials And Methods
[47]
Niche conservatism and ecological change during the Late ...
Apr 5, 2023 · We examine regional-scale ecological changes resulting from a Late Devonian mass extinction event using brachiopod fossil assemblages from the Appalachian ...
[48]
Study reshapes understanding of mass extinction in Late Devonian ...
Dec 6, 2023 · The work is the first to unify two competing Late Devonian extinction theories into a comprehensive cause-and-effect scenario.
[49]
Conodont apatite δ 18 O signatures indicate climatic cooling as a ...
Jun 2, 2017 · Conodont apatite δ18O signatures indicate climatic cooling as a trigger of the Late Devonian mass extinction Available. Michael M. Joachimski ...<|separator|>
[50]
Intensified Ocean Deoxygenation During the end Devonian Mass ...
Dec 15, 2019 · Recent oxygen isotope data of conodont apatite suggests that sea-surface temperature declined by 3°C–4°C in the latest Devonian (Figure 5; ...
[51]
Multiple diachronous “Black Seas” mimic global ocean anoxia ...
Aug 7, 2023 · We suggest instead that black shales near the DCB record multiple, but diachronous, Black Sea–like basins around the globe, promoted by the Late Devonian ...
[52]
Widespread Late Devonian marine anoxia in eastern North America
Specifically, Late Devonian black shale deposition in eastern North America coincides with the acme of the Acadian orogeny and the Late Devonian mass extinction ...
[53]
Mass extinctions and sea-level changes - ScienceDirect.com
Newell's hypothesis that marine extinctions are related to shelf habitat loss during severe regression remains tenable for the end Guadalupian and end Triassic ...
[54]
Appalachian Basin mercury enrichments during the Late Devonian ...
Oct 1, 2023 · We present new mercury (Hg) data from the Late Devonian of the Appalachian Basin. We find no volcanogenic Hg anomalies during the Kellwasser Events.
[55]
Study reshapes understanding of mass extinction in Late Devonian ...
Dec 6, 2023 · Some scientists argue the Late Devonian mass extinction was caused by large-scale volcanic eruptions, causing global cooling. Others argue a ...
[56]
Terrestrial-marine teleconnections in the Devonian: links between ...
Long–term effects included drawdown of atmospheric pCO2 and global cooling, leading to a brief Late Devonian glaciation, which set the stage for icehouse ...<|control11|><|separator|>
[57]
(PDF) New 40Ar/39Ar and K–Ar ages of the Viluy traps (Eastern ...
Aug 6, 2025 · The atmospheric CO 2 level decreased during the Middle-Late Devonian interval (Berner, 2001), leading to a gradual cooling (e.g., Algeo et al., ...
[58]
Mass extinction facts and information from National Geographic
Sep 26, 2019 · Late Devonian extinction - 383-359 million years ago. Starting 383 million years ago, this extinction event eliminated about 75 percent of all ...Missing: 70%
[59]
Mercury Anomalies Link to Extensive Volcanism Across the Late ...
Jul 5, 2021 · These three extinction events were named the Lower Kellwasser Event (372.5 Ma) from the latest Frasnian stage, the Upper Kellwasser Event near ...
[60]
Laser argon dating of melt breccias from the Siljan impact structure ...
Jan 26, 2010 · Abstract— In earlier studies, the 65-75 km diameter Siljan impact structure in Sweden has been linked to the Late Devonian mass extinction ...
[61]
Microtektites and Mass Extinctions: Evidence for a Late Devonian ...
The presence of microtektites near the F/F boundary supports the hypothesis that an impact caused the Upper Devonian worldwide benthic mass extinctions.Missing: layer | Show results with:layer
[62]
Laser argon dating of melt breccias from the Siljan impact structure ...
Aug 7, 2025 · Other evidence reported for Late Devonian extraterrestrial impacts include the strong iridium anomaly in the Canning Basin, Western ...
[63]
Enhanced Continental Weathering as a Trigger for the End ...
Jun 9, 2023 · Late Devonian weathering rate changes have been attributed to increased global orogenic uplift (Averbuch et al., 2005) by analogy with the Late ...
[64]
Pulses of enhanced continental weathering associated with multiple ...
The Late Devonian (~383–359 Ma) marked a time of numerous environmental and biotic crises, including one of the 'Big Five' mass extinctions of the Phanerozoic ...
[65]
Supernova triggers for end-Devonian extinctions - PMC - NIH
We therefore propose that the end-Devonian extinctions were triggered by supernova explosions at ∼ 20 pc, somewhat beyond the “kill distance.”
[66]
Earth's atmosphere protects the biosphere from nearby supernovae
Jun 14, 2024 · We find that the effect of a short burst of gamma rays is small since they are strongly attenuated before reaching the lower stratosphere.
[67]
(PDF) Extinction cascades and catastrophe in ancient food webs
Aug 6, 2025 · The frequency of catastrophic secondary extinction increases as food web complexity increases, but increased complexity also serves to dampen ...
[68]
Quantitative analysis of the ecological dominance of benthic disaster ...
Apr 28, 2016 · These disaster taxa include the bivalve genera Claraia, Unionites, Eumorphotis, and Promyalina, and the inarticulate brachiopod Lingularia. The ...
[69]
The Late Devonian extinction event: evidence for abrupt ecosystem ...
Feb 8, 2016 · Extinction rates are elevated for a period of at least 2 to 4 m.y. during the middle and late phases of the Frasnian, with maximum rates ...<|separator|>
[70]
Late Devonian–early Carboniferous ostracods (Crustacea) from ...
Mar 15, 2022 · The specific extinction and renewal rates are estimated at 44% and 62%, respectively. The main factor of the post–crisis renewal of ostracod ...<|separator|>
[71]
Global microbial carbonate proliferation after the end-Devonian ...
Dec 23, 2016 · The Hangenberg mass extinction eliminated >45% genera of marine invertebrates, including dominant reef-building organisms (stromatoporoids and ...
[72]
Life in the Aftermath of Mass Extinctions - Cell Press
Oct 5, 2015 · Benthic taxa, by contrast, gener- ally took more than 5 million years to fully recover pre-extinction levels of diversity and community ...
[73]
End-Devonian extinction and a bottleneck in the early evolution of ...
Key questions about vertebrate evolution in the Late Devonian concern the timing of the faunal turnover, the magnitude of extinction pulses (if any), and ...
[74]
Re-emergence of coral reef ecosystems after the Late Devonian ...
Here, we document and review the reef-recovery interval following the Late Devonian Frasnian-Famennian (Kellwasser) and end-Famennian (Hangenberg) mass ...
[75]
Page not found | Nature
Insufficient relevant content.
[76]
Niche conservatism and ecological change during the Late ...
Apr 5, 2023 · Here, we examine regional-scale ecological changes resulting from a Late Devonian mass extinction event using brachiopod fossil assemblages from ...