Last updated

419.2 ± 3.2 – 358.9 ± 0.4 Ma
Late Devonian palaeogeographic map.jpg
Late Devonian world map
Name formalityFormal
Nickname(s)Age of Fishes
Usage information
Celestial body Earth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Chronological unit Period
Stratigraphic unit System
Time span formalityFormal
Lower boundary definition FAD of the Graptolite Monograptus uniformis
Lower boundary GSSP Klonk, Czech Republic
49°51′18″N13°47′31″E / 49.8550°N 13.7920°E / 49.8550; 13.7920
GSSP ratified1972 [5]
Upper boundary definitionFAD of the Conodont Siphonodella sulcata (discovered to have biostratigraphic issues as of 2006). [6]
Upper boundary GSSP La Serre, Montagne Noire, France
43°33′20″N3°21′26″E / 43.5555°N 3.3573°E / 43.5555; 3.3573
GSSP ratified1990 [7]
Atmospheric and climatic data
Sea level above present dayRelatively steady around 189 m, gradually falling to 120 m through period [8]

The Devonian ( /dɪˈvni.ən,dɛ-/ də-VOH-nee-ən, de-) [9] [10] is a geologic period and system of the Paleozoic, spanning 60.3 million years from the end of the Silurian, 419.2 million years ago (Mya), to the beginning of the Carboniferous, 358.9 Mya. [11] It is named after Devon, England, where rocks from this period were first studied.


The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period.

Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating almost every known aquatic environment. The ancestors of all four-limbed vertebrates (tetrapods) began adapting to walk on land, as their strong pectoral and pelvic fins gradually evolved into legs, though they were not fully established until the Late Carboniferous. [12] In the oceans, primitive sharks became more numerous than in the Silurian and Late Ordovician.

The first ammonites, a subclass of molluscs, appeared. Trilobites, the mollusc-like brachiopods, and the great coral reefs were still common. The Late Devonian extinction which started about 375 million years ago [13] severely affected marine life, killing off all placodermi, and all trilobites, save for a few species of the order Proetida.

Devonian palaeogeography was dominated by the supercontinent of Gondwana to the south, the small continent of Siberia to the north, and the medium-sized continent of Laurussia to the east. Major tectonic events include the closure of the Rheic Ocean, the separation of South China from Gondwana, and the resulting expansion of the Paleo-Tethys Ocean. The Devonian experienced several major mountain-building events as Laurussia and Gondwana approached; these include the Acadian Orogeny in North America and the beginning of the Variscan Orogeny in Europe. These early collisions preceded the formation of Pangaea in the Late Paleozoic.


The rocks of Lummaton Quarry in Torquay in Devon played an early role in defining the Devonian Period Lummaton Quarry 1.JPG
The rocks of Lummaton Quarry in Torquay in Devon played an early role in defining the Devonian Period

The period is named after Devon, a county in southwestern England, where a controversial argument in the 1830s over the age and structure of the rocks found distributed throughout the county was eventually resolved by the definition of the Devonian Period in the geological timescale. The Great Devonian Controversy was a long period of vigorous argument and counter-argument between the main protagonists of Roderick Murchison with Adam Sedgwick against Henry De la Beche supported by George Bellas Greenough. Murchison and Sedgwick won the debate and named the period they proposed as the Devonian System. [14] [15] [lower-alpha 1]

While the rock beds that define the start and end of the Devonian Period are well identified, the exact dates are uncertain. According to the International Commission on Stratigraphy, [19] the Devonian extends from the end of the Silurian 419.2 Mya, to the beginning of the Carboniferous 358.9 Mya – in North America, at the beginning of the Mississippian subperiod of the Carboniferous.

In 19th century texts the Devonian has been called the "Old Red Age", after the red and brown terrestrial deposits known in the United Kingdom as the Old Red Sandstone in which early fossil discoveries were found. Another common term is "Age of the Fishes", [20] referring to the evolution of several major groups of fish that took place during the period. Older literature on the Anglo-Welsh basin divides it into the Downtonian, Dittonian, Breconian, and Farlovian stages, the latter three of which are placed in the Devonian. [21]

The Devonian has also erroneously been characterised as a "greenhouse age", due to sampling bias: most of the early Devonian-age discoveries came from the strata of western Europe and eastern North America, which at the time straddled the Equator as part of the supercontinent of Euramerica where fossil signatures of widespread reefs indicate tropical climates that were warm and moderately humid. In fact the climate in the Devonian differed greatly during its epochs and between geographic regions. For example, during the Early Devonian, arid conditions were prevalent through much of the world including Siberia, Australia, North America, and China, but Africa and South America had a warm temperate climate. In the Late Devonian, by contrast, arid conditions were less prevalent across the world and temperate climates were more common.[ citation needed ]


The Devonian Period is formally broken into Early, Middle and Late subdivisions. The rocks corresponding to those epochs are referred to as belonging to the Lower, Middle and Upper parts of the Devonian System.

Early Devonian

The Early Devonian lasted from 419.2 ± 3.2 to 393.3 ± 0.4 and began with the Lochkovian Stage 419.2 ± 3.2 to 410.8 ± 0.4, which was followed by the Pragian from 410.8 ± 3.2 to 407.6 ± 0.4 and then by the Emsian, which lasted until the Middle Devonian began, 393.3 ± 1.2 million years ago. [22] During this time, the first ammonoids appeared, descending from bactritoid nautiloids. Ammonoids during this time period were simple and differed little from their nautiloid counterparts. These ammonoids belong to the order Agoniatitida, which in later epochs evolved to new ammonoid orders, for example Goniatitida and Clymeniida. This class of cephalopod molluscs would dominate the marine fauna until the beginning of the Mesozoic Era.

Middle Devonian

The Middle Devonian comprised two subdivisions: first the Eifelian, which then gave way to the Givetian 387.7 ± 0.8 million years ago. During this time the jawless agnathan fishes began to decline in diversity in freshwater and marine environments partly due to drastic environmental changes and partly due to the increasing competition, predation, and diversity of jawed fishes. The shallow, warm, oxygen-depleted waters of Devonian inland lakes, surrounded by primitive plants, provided the environment necessary for certain early fish to develop such essential characteristics as well developed lungs, and the ability to crawl out of the water and onto the land for short periods of time. [23]

Late Devonian

Finally, the Late Devonian started with the Frasnian, 382.7 ± 3.2 to 372.2 ± 0.4, during which the first forests took shape on land. The first tetrapods appeared in the fossil record in the ensuing Famennian subdivision, the beginning and end of which are marked with extinction events. This lasted until the end of the Devonian, 358.9 ± 0.4 million years ago. [22]


The Devonian was a relatively warm period, and probably lacked any glaciers for much of the period. The temperature gradient from the equator to the poles was not as large as it is today. The weather was also very arid, mostly along the equator where it was the driest. [24] Reconstruction of tropical sea surface temperature from conodont apatite implies an average value of 30 °C (86 °F) in the Early Devonian. [24] CO2 levels dropped steeply throughout the Devonian Period. The newly evolved forests drew carbon out of the atmosphere, which were then buried into sediments. This may be reflected by a Mid-Devonian cooling of around 5 °C (9 °F). [24] The Late Devonian warmed to levels equivalent to the Early Devonian; while there is no corresponding increase in CO2 concentrations, continental weathering increases (as predicted by warmer temperatures); further, a range of evidence, such as plant distribution, points to a Late Devonian warming. [24] The climate would have affected the dominant organisms in reefs; microbes would have been the main reef-forming organisms in warm periods, with corals and stromatoporoid sponges taking the dominant role in cooler times. The warming at the end of the Devonian may even have contributed to the extinction of the stromatoporoids. At the terminus of the Devonian, Earth rapidly cooled into an icehouse, marking the beginning of the Late Palaeozoic Ice Age. [25] [26]


The Devonian world involved many continents and ocean basins of various sizes. The largest continent, Gondwana, was located entirely within the Southern Hemisphere. It corresponds to modern day South America, Africa, Australia, Antarctica, and India, as well as minor components of North America and Asia. The second-largest continent, Laurussia, was northwest of Gondwana, and corresponds to much of modern-day North America and Europe. Various smaller continents, microcontinents, and terranes were present east of Laurussia and north of Gondwana, corresponding to parts of Europe and Asia. The Devonian Period was a time of great tectonic activity, as the major continents of Laurussia and Gondwana drew closer together. [27] [28]

Sea levels were high worldwide, and much of the land lay under shallow seas, where tropical reef organisms lived. The enormous "world ocean", Panthalassa, occupied much of the Northern Hemisphere as well as wide swathes east of Gondwana and west of Laurussia. Other minor oceans were the Paleo-Tethys Ocean and Rheic Ocean. [27] [28]


Continental boundary of Laurussia (Euramerica) and its constituents, superimposed onto modern coastlines Laurussia Euramerica.svg
Continental boundary of Laurussia (Euramerica) and its constituents, superimposed onto modern coastlines

By the early Devonian, the continent Laurussia (also known as Euramerica) was fully formed through the collision of the continents Laurentia (modern day North America) and Baltica (modern day northern and eastern Europe). The tectonic effects of this collision continued into the Devonian, producing a string of mountain ranges along the southeastern coast of the continent. In present-day eastern North America, the Acadian Orogeny continued to raise the Appalachian Mountains. Further east, the collision also extended the rise of the Caledonian Mountains of Great Britain and Scandinavia. As the Caledonian Orogeny wound down in the later part of the period, orogenic collapse facilitated a cluster of granite intrusions in Scotland. [27]

Most of Laurussia was located south of the equator, but in the Devonian it moved northwards and began to rotate counterclockwise towards its modern position. While the most northern parts of the continent (such as Greenland and Ellesmere Island) established tropical conditions, most of the continent was located within the natural dry zone along the Tropic of Capricorn, which (as nowadays) is a result of the convergence of two great air-masses, the Hadley cell and the Ferrel cell. In these near-deserts, the Old Red Sandstone sedimentary beds formed, made red by the oxidised iron (hematite) characteristic of drought conditions. The abundance of red sandstone on continental land also lends Laurussia the name "the Old Red Continent". [29] For much of the Devonian, the majority of western Laurussia (North America) was covered by subtropical inland seas which hosted a diverse ecosystem of reefs and marine life. Devonian marine deposits are particularly prevalent in the midwestern and northeastern United States. Devonian reefs also extended along the southeast edge of Laurussia, a coastline now corresponding to southern England, Belgium, and other mid-latitude areas of Europe. [27]

In the Early and Middle Devonian, the west coast of Laurussia was a passive margin with broad coastal waters, deep silty embayments, river deltas and estuaries, found today in Idaho and Nevada. In the Late Devonian, an approaching volcanic island arc reached the steep slope of the continental shelf and began to uplift deep water deposits. This minor collision sparked the start of a mountain-building episode called the Antler orogeny, which extended into the Carboniferous. [30] [27] Mountain building could also be found in the far northeastern extent of the continent, as minor tropical island arcs and detached Baltic terranes re-join the continent. Deformed remnants of these mountains can still be found on Ellesmere Island and Svalbard. Many of the Devonian collisions in Laurussia produce both mountain chains and foreland basins, which are frequently fossiliferous. [27] [28]


The Early-Middle Devonian world, with major continents Gondwana (Go), Euramerica/Laurussia (Eu), and Siberia (Si) Early-Middle Devonian chasmataspids paleogeography.png
The Early-Middle Devonian world, with major continents Gondwana (Go), Euramerica/Laurussia (Eu), and Siberia (Si)

Gondwana was by far the largest continent on the planet. It was completely south of the equator, although the northeastern sector (now Australia) did reach tropical latitudes. The southwestern sector (now South America) was located to the far south, with Brazil situated near the South Pole. The northwestern edge of Gondwana was an active margin for much of the Devonian, and saw the accretion of many smaller land masses and island arcs. These include Chilenia, Cuyania, and Chaitenia, which now form much of Chile and Patagonia. [27] [31] These collisions were associated with volcanic activity and plutons, but by the Late Devonian the tectonic situation had relaxed and much of South America was covered by shallow seas. These south polar seas hosted a distinctive brachiopod fauna, the Malvinokaffric Realm, which extended eastward to marginal areas now equivalent to South Africa and Antarctica. Malvinokaffric faunas even managed to approach the South Pole via a tongue of Panthalassa which extended into the Paraná Basin. [27]

The northern rim of Gondwana was mostly a passive margin, hosting extensive marine deposits in areas such as northwest Africa and Tibet. The eastern margin, though warmer than the west, was equally active. Numerous mountain building events and granite and kimberlite intrusions affected areas equivalent to modern day eastern Australia, Tasmania, and Antarctica. [27]

Asian terranes

The earth at 380 Ma, centered on the Paleo-Tethys Ocean, which fully opened during the Devonian 380 Ma plate tectonic reconstruction.png
The earth at 380 Ma, centered on the Paleo-Tethys Ocean, which fully opened during the Devonian

Several island microcontinents (which would later coalesce into modern day Asia) stretched over a low-latitude archipelago to the north of Gondwana. They were separated from the southern continent by an oceanic basin: the Paleo-Tethys. Although the western Paleo-Tethys Ocean had existed since the Cambrian, the eastern part only began to rift apart as late as the Silurian. This process accelerated in the Devonian. The eastern branch of the Paleo-Tethys was fully opened when South China and Annamia (a terrane equivalent to most of Indochina), together as a unified continent, detached from the northeastern sector of Gondwana. Nevertheless, they remained close enough to Gondwana that their Devonian fossils were more closely related to Australian species than to north Asian species. Other Asian terranes remained attached to Gondwana, including Sibumasu (western Indochina), Tibet, and the rest of the Cimmerian blocks. [27] [28]

World map at 400 Ma (Early Devonian), showing continents and terranes with modern continent borders superimposed Nostolepis distribution Early Devonian paleogeography.png
World map at 400 Ma (Early Devonian), showing continents and terranes with modern continent borders superimposed

While the South China-Annamia continent was the newest addition to the Asian microcontinents, it was not the first. North China and the Tarim Block (now northwesternmost China) were located westward and continued to drift northwards, powering over older oceanic crust in the process. Further west was a small ocean (the Turkestan Ocean), followed by the larger microcontinents of Kazakhstania, Siberia, and Amuria. Kazakhstania was a volcanically active region during the Devonian, as it continued to assimilate smaller island arcs. [27]

Siberia was located just north of the equator as the largest landmass in the Northern Hemisphere. At the beginning of the Devonian, Siberia was inverted (upside down) relative to its modern orientation. Later in the period it moved northwards and began to twist clockwise, though it was not near its modern location. Siberia approached the eastern edge of Laurussia as the Devonian progressed, but it was still separated by a seaway, the Ural Ocean. Although Siberia's margins were generally tectonically stable and ecologically productive, rifting and deep mantle plumes impacted the continent with flood basalts during the Late Devonian. The Altai-Sayan region was shaken by volcanism in the Early and Middle Devonian, while Late Devonian magmatism was magnified further to produce the Vilyuy Traps, flood basalts which may have contributed to the Late Devonian Mass Extinction. The last major round of volcanism, the Yakutsk Large Igneous Province, continued into the Carboniferous to produce extensive kimberlite deposits. [27] [28]

Similar volcanic activity also affected the nearby microcontinent of Amuria (now Manchuria, Mongolia and their vicinities). Though certainly close to Siberia in the Devonian, the precise location of Amuria is uncertain due to contradictory paleomagnetic data. [27]

Closure of the Rheic Ocean

The Rheic Ocean, which separated Laurussia from Gondwana, was wide at the start of the Devonian, having formed after the drift of Avalonia away from Gondwana. It steadily shrunk as the period continued, as the two major continents approached near the equator in the early stages of the assembly of Pangaea. The closure of the Rheic Ocean began in the Devonian and continued into the Carboniferous. As the ocean narrowed, endemic marine faunas of Gondwana and Laurussia combined into a single tropical fauna. The history of the western Rheic Ocean is a subject of debate, but there is good evidence that Rheic oceanic crust experienced intense subduction and metamorphism under Mexico and Central America. [27] [28]

The closure of the eastern part of the Rheic Ocean is associated with the assemblage of central and southern Europe. In the early Paleozoic, much of Europe was still attached to Gondwana, including the terranes of Iberia, Armorica (France), Palaeo-Adria (the western Mediterranean area), Bohemia, Franconia, and Saxothuringia. These continental blocks, collectively known as the Armorican Terrane Assemblage, split away from Gondwana in the Silurian and drifted towards Laurussia through the Devonian. Their collision with Laurussia leads to the beginning of the Variscan Orogeny, a major mountain-building event which would escalate further in the Late Paleozoic. Franconia and Saxothuringia collided with Laurussia near the end of the Early Devonian, pinching out the easternmost Rheic Ocean. The rest of the Armorican terranes followed, and by the end of the Devonian they were fully connected with Laurussia. This sequence of rifting and collision events led to the successive creation and destruction of several small seaways, including the Rheno-Hercynian, Saxo-Thuringian, and Galicia-Moldanubian oceans. Their sediments were eventually compressed and completely buried as Gondwana fully collided with Laurussia in the Carboniferous. [32] [27] [28]


Marine biota

Spindle diagram for the evolution of vertebrates Fish evolution.png
Spindle diagram for the evolution of vertebrates

Sea levels in the Devonian were generally high. Marine faunas continued to be dominated by bryozoa, diverse and abundant brachiopods, the enigmatic hederellids, microconchids and corals. Lily-like crinoids (animals, their resemblance to flowers notwithstanding) were abundant, and trilobites were still fairly common. Bivalves became commonplace in deep water and outer shelf environments. [34] The first ammonites also appeared during or slightly before the early Devonian Period around 400 Mya. [35] Bactritoids make their first appearance in the Early Devonian as well; their radiation, along with that of ammonoids, has been attributed by some authors to increased environmental stress resulting from decreasing oxygen levels in the deeper parts of the water column. [36] Among vertebrates, jawless armored fish (ostracoderms) declined in diversity, while the jawed fish (gnathostomes) simultaneously increased in both the sea and fresh water. Armored placoderms were numerous during the lower stages of the Devonian Period and became extinct in the Late Devonian, perhaps because of competition for food against the other fish species. Early cartilaginous (Chondrichthyes) and bony fishes (Osteichthyes) also become diverse and played a large role within the Devonian seas. The first abundant genus of shark, Cladoselache , appeared in the oceans during the Devonian Period. The great diversity of fish around at the time has led to the Devonian being given the name "The Age of Fish" in popular culture. [37]

The Devonian saw significant expansion in diversity of nektonic marine life driven by the abundance of planktonic microorganisms in the free water column as well as high ecological competition in benthic habitats, which were extremely saturated; this diversification has been labelled the Devonian Nekton Revolution by many researchers. [38] However, other researchers have questioned whether this revolution existed at all; a 2018 study found that although the proportion of biodiversity constituted by nekton increased across the boundary between the Silurian and Devonian, it decreased across the span of the Devonian, particularly during the Pragian, and that the overall diversity of nektonic taxa did not increase significantly during the Devonian compared to during other geologic periods, and was in fact higher during the intervals spanning from the Wenlock to the Lochkovian and from the Carboniferous to the Permian. The study's authors instead attribute increased overall diversity of nekton in the Devonian to a broader, gradual trend of nektonic diversification across the entire Palaeozoic. [39]


A now-dry barrier reef, located in present-day Kimberley Basin of northwest Australia, once extended 350 km (220 mi), fringing a Devonian continent. [40] Reefs are generally built by various carbonate-secreting organisms that have the ability to erect wave-resistant structures near sea level. Although modern reefs are constructed mainly by corals and calcareous algae, Devonian reefs were either microbial reefs built up mostly by autotrophic cyanobacteria, or coral-stromatoporoid reefs built up by coral-like stromatoporoids and tabulate and rugose corals. Microbial reefs dominated under the warmer conditions of the early and late Devonian, while coral-stromatoporoid reefs dominated during the cooler middle Devonian. [41]

Terrestrial biota

Prototaxites milwaukeensis, a large fungus, initially thought to be a marine alga, from the Middle Devonian of Wisconsin Prototaxites milwaukeensis.jpg
Prototaxites milwaukeensis, a large fungus, initially thought to be a marine alga, from the Middle Devonian of Wisconsin

By the Devonian Period, life was well underway in its colonisation of the land. The moss forests and bacterial and algal mats of the Silurian were joined early in the period by primitive rooted plants that created the first stable soils and harbored arthropods like mites, scorpions, trigonotarbids [42] and myriapods (although arthropods appeared on land much earlier than in the Early Devonian [43] and the existence of fossils such as Protichnites suggest that amphibious arthropods may have appeared as early as the Cambrian). By far the largest land organism at the beginning of this period was the enigmatic Prototaxites , which was possibly the fruiting body of an enormous fungus, [44] rolled liverwort mat, [45] or another organism of uncertain affinities [46] that stood more than 8 metres (26 ft) tall, and towered over the low, carpet-like vegetation during the early part of the Devonian. Also the first possible fossils of insects appeared around 416 Mya, in the Early Devonian. Evidence for the earliest tetrapods takes the form of trace fossils in shallow lagoon environments within a marine carbonate platform / shelf during the Middle Devonian, [47] although these traces have been questioned and an interpretation as fish feeding traces ( Piscichnus ) has been advanced. [48]

The greening of land

The Devonian Period marks the beginning of extensive land colonisation by plants. With large land-dwelling herbivores not yet present, large forests grew and shaped the landscape. Devonianscene-green.jpg
The Devonian Period marks the beginning of extensive land colonisation by plants. With large land-dwelling herbivores not yet present, large forests grew and shaped the landscape.

Many Early Devonian plants did not have true roots or leaves like extant plants, although vascular tissue is observed in many of those plants. Some of the early land plants such as Drepanophycus likely spread by vegetative growth and spores. [49] The earliest land plants such as Cooksonia consisted of leafless, dichotomous axes and terminal sporangia and were generally very short-statured, and grew hardly more than a few centimetres tall. [50] Fossils of Armoricaphyton chateaupannense , about 400 million years old, represent the oldest known plants with woody tissue. [51] By the Middle Devonian, shrub-like forests of primitive plants existed: lycophytes, horsetails, ferns, and progymnosperms evolved. Most of these plants had true roots and leaves, and many were quite tall. The earliest-known trees appeared in the Middle Devonian. [52] These included a lineage of lycopods and another arborescent, woody vascular plant, the cladoxylopsids and progymnosperm Archaeopteris . [53] These tracheophytes were able to grow to large size on dry land because they had evolved the ability to biosynthesize lignin, which gave them physical rigidity and improved the effectiveness of their vascular system while giving them resistance to pathogens and herbivores. [54] These are the oldest-known trees of the world's first forests. By the end of the Devonian, the first seed-forming plants had appeared. This rapid appearance of many plant groups and growth forms has been referred to as the Devonian Explosion or the Silurian-Devonian Terrestrial Revolution. [55]

The 'greening' of the continents acted as a carbon sink, and atmospheric concentrations of carbon dioxide may have dropped. This may have cooled the climate and led to a massive extinction event. (See Late Devonian extinction).

Animals and the first soils

Primitive arthropods co-evolved with this diversified terrestrial vegetation structure. The evolving co-dependence of insects and seed-plants that characterised a recognisably modern world had its genesis in the Late Devonian Epoch. The development of soils and plant root systems probably led to changes in the speed and pattern of erosion and sediment deposition. The rapid evolution of a terrestrial ecosystem that contained copious animals opened the way for the first vertebrates to seek a terrestrial living. By the end of the Devonian, arthropods were solidly established on the land. [56]

Late Devonian extinction

The Late Devonian is characterised by three episodes of extinction ("Late D") Extinction Intensity.svg
The Late Devonian is characterised by three episodes of extinction ("Late D")

The Late Devonian extinction is not a single event, but rather is a series of pulsed extinctions at the Givetian-Frasnian boundary, the Frasnian-Famennian boundary, and the Devonian-Carboniferous boundary. [57] Together, these are considered one of the "Big Five" mass extinctions in Earth's history. [58] The Devonian extinction crisis primarily affected the marine community, and selectively affected shallow warm-water organisms rather than cool-water organisms. The most important group to be affected by this extinction event were the reef-builders of the great Devonian reef systems. [59]

Amongst the severely affected marine groups were the brachiopods, trilobites, ammonites, and acritarchs, and the world saw the disappearance of an estimated 96% of vertebrates like conodonts and bony fishes, and all of the ostracoderms and placoderms. [60] [57] Land plants as well as freshwater species, such as our tetrapod ancestors, were relatively unaffected by the Late Devonian extinction event (there is a counterargument that the Devonian extinctions nearly wiped out the tetrapods [61] ).

The reasons for the Late Devonian extinctions are still unknown, and all explanations remain speculative. [62] [63] [64] [65] Canadian paleontologist Digby McLaren suggested in 1969 that the Devonian extinction events were caused by an asteroid impact. However, while there were Late Devonian collision events (see the Alamo bolide impact), little evidence supports the existence of a large enough Devonian crater. [66]

See also



  1. Sedgwick and Murchison coined the term "Devonian system" in 1840: [16] "We propose therefore, for the future, to designate these groups collectively by the name Devonian system". Sedgwick and Murchison acknowledged William Lonsdale's role in proposing, on the basis of fossil evidence, the existence of a Devonian stratum between those of the Silurian and Carboniferous periods: [17] "Again, Mr. Lonsdale, after an extensive examination of the fossils of South Devon, had pronounced them, more than a year since, to form a group intermediate between those of the Carboniferous and Silurian systems". William Lonsdale stated that in December 1837 he had suggested the existence of a stratum between the Silurian and Carboniferous ones: [18] "Mr. Austen's communication [was] read December 1837 ... . It was immediately after the reading of that paper ... that I formed the opinion relative to the limestones of Devonshire being of the age of the old red sandstone; and which I afterwards suggested first to Mr. Murchison and then to Prof. Sedgwick".

Related Research Articles

The Carboniferous is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period 358.9 million years ago (Mya), to the beginning of the Permian Period, 298.9 million years ago. The name Carboniferous means "coal-bearing", from the Latin carbō ("coal") and ferō, and refers to the many coal beds formed globally during that time.

The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya.

The PaleozoicEra is the earliest of three geologic eras of the Phanerozoic Eon. The name Paleozoic was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words palaiós and zōḗ, "life", meaning "ancient life").

<span class="mw-page-title-main">Phanerozoic</span> Fourth and current eon of the geological timescale

The Phanerozoic Eon is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. It covers 538.8 million years to the present, and it began with the Cambrian Period, when animals first developed hard shells preserved in the fossil record. The time before the Phanerozoic, called the Precambrian, is now divided into the Hadean, Archaean and Proterozoic eons.

<span class="mw-page-title-main">Silurian</span> Third period of the Paleozoic Era 444-419 million years ago

The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out.

<span class="mw-page-title-main">Laurasia</span> Northern landmass that formed part of the Pangaea supercontinent

Laurasia was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago (Mya), the other being Gondwana. It separated from Gondwana 215 to 175 Mya during the breakup of Pangaea, drifting farther north after the split and finally broke apart with the opening of the North Atlantic Ocean c. 56 Mya. The name is a portmanteau of Laurentia and Asia.

<span class="mw-page-title-main">Late Devonian extinction</span> One of the five most severe extinction events in the history of the Earths biota

The Late Devonian extinction consisted of several extinction events in the Late Devonian Epoch, which collectively represent one of the five largest mass extinction events in the history of life on Earth. The term primarily refers to a major extinction, the Kellwasser event, which occurred around 372 million years ago, at the boundary between the Frasnian stage and the Famennian stage, the last stage in the Devonian Period. Overall, 19% of all families and 50% of all genera became extinct. A second mass extinction, the Hangenberg event, occurred 359 million years ago, bringing an end to the Famennian and Devonian, as the world transitioned into the Carboniferous Period.

Romer's gap is an example of an apparent gap in the tetrapod fossil record used in the study of evolutionary biology. Such gaps represent periods from which excavators have not yet found relevant fossils. Romer's gap is named after paleontologist Alfred Romer, who first recognised it. Recent discoveries in Scotland are beginning to close this gap in palaeontological knowledge.

<span class="mw-page-title-main">Caledonian orogeny</span> Mountain building event caused by the collision of Laurentia, Baltica and Avalonia

The Caledonian orogeny was a mountain-building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly 490–390 million years ago (Ma). It was caused by the closure of the Iapetus Ocean when the continents and terranes of Laurentia, Baltica and Avalonia collided.

<span class="mw-page-title-main">Variscan orogeny</span> Collision of tectonic plates resulting in the creation of mountains

The Variscan or Hercynianorogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea.

The Rheic Ocean was an ocean which separated two major palaeocontinents, Gondwana and Laurussia (Laurentia-Baltica-Avalonia). One of the principal oceans of the Palaeozoic, its sutures today stretch 10,000 km (6,200 mi) from Mexico to Turkey and its closure resulted in the assembly of the supercontinent Pangaea and the formation of the Variscan–Alleghenian–Ouachita orogenies.

The natural history of Australia has been shaped by the geological evolution of the Australian continent from Gondwana and the changes in global climate over geological time. The building of the Australian continent and its association with other land masses, as well as climate changes over geological time, have created the unique flora and fauna present in Australia today.

The Proto-Tethys or Theic Ocean was an ancient ocean that existed from the latest Ediacaran to the Carboniferous.

<span class="mw-page-title-main">Geological history of Earth</span> The sequence of major geological events in Earths past

The geological history of Earth follows the major geological events in Earth's past based on the geological time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.

The Hangenberg event, also known as the Hangenberg crisis or end-Devonian extinction, is a mass extinction that occurred at the end of the Famennian stage, the last stage in the Devonian Period. It is usually considered the second-largest extinction in the Devonian Period, having occurred approximately 13 million years after the Late Devonian mass extinction at the Frasnian-Famennian boundary. The Hangenberg event was an anoxic event marked by a layer of black shale, and it has been proposed to have been related to a rapid sea-level fall from the last phase of the Devonian Southern Hemisphere glaciation. It has also been suggested to have been linked to an increase in terrestrial plant cover. That would have led to increased nutrient supply in rivers and may have led to eutrophication of semi-restricted epicontinental seas and could have stimulated algal blooms. However, support for a rapid increase in plant cover at the end of the Famennian is lacking. The event is named after the Hangenberg Shale, which is part of a sequence that straddles the Devonian-Carboniferous boundary in the Rhenish Massif of Germany.

<span class="mw-page-title-main">Gondwana</span> Neoproterozoic to Cretaceous landmass

Gondwana was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic and began to break up during the Jurassic period. The final stages of break-up, involving the separation of Antarctica from South America and Australia, occurred during the Paleogene. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name, it is also commonly called Gondwanaland.

<span class="mw-page-title-main">Pangaea</span> Supercontinent from the late Paleozoic to early Mesozoic eras

Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million years ago, and began to break apart about 200 million years ago, at the end of the Triassic and beginning of the Jurassic. In contrast to the present Earth and its distribution of continental mass, Pangaea was centred on the equator and surrounded by the superocean Panthalassa and the Paleo-Tethys and subsequent Tethys Oceans. Pangaea is the most recent supercontinent to have existed and the first to be reconstructed by geologists.

<span class="mw-page-title-main">Rhenohercynian Zone</span> Fold belt of west and central Europe, formed during the Hercynian orogeny

The Rhenohercynian Zone or Rheno-Hercynian zone in structural geology describes a fold belt of west and central Europe, formed during the Hercynian orogeny. The zone consists of folded and thrust Devonian and early Carboniferous sedimentary rocks that were deposited in a back-arc basin along the southern margin of the then existing paleocontinent Laurussia.

A paleocontinent or palaeocontinent is a distinct area of continental crust that existed as a major landmass in the geological past. There have been many different landmasses throughout Earth's time. They range in sizes, some are just a collection of small microcontinents while others are large conglomerates of crust. As time progresses and sea levels rise and fall more crust can be exposed making way for larger landmasses. The continents of the past shaped the evolution of organisms on Earth and contributed to the climate of the globe as well. As landmasses break apart, species are separated and those that were once the same now have evolved to their new climate. The constant movement of these landmasses greatly determines the distribution of organisms on Earth's surface. This is evident with how similar fossils are found on completely separate continents. Also, as continents move, mountain building events (orogenies) occur, causing a shift in the global climate as new rock is exposed and then there is more exposed rock at higher elevations. This causes glacial ice expansion and an overall cooler global climate. Which effects the overall global climate trend of Earth. The movement of the continents greatly affects the overall dispersal of organisms throughout the world and the trend in climate throughout Earth's history. Examples include Laurentia, Baltica and Avalonia, which collided together during the Caledonian orogeny to form the Old Red Sandstone paleocontinent of Laurussia. Another example includes a collision that occurred during the late Pennsylvanian and early Permian time when there was a collision between the two continents of Tarimsky and Kirghiz-Kazakh. This collision was caused because of their askew convergence when the paleoceanic basin closed.

<span class="mw-page-title-main">Evolution of fish</span> Origin and diversification of fish through geologic time

The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys. During the late Cambrian, eel-like jawless fish called the conodonts, and small mostly armoured fish known as ostracoderms, first appeared. Most jawless fish are now extinct; but the extant lampreys may approximate ancient pre-jawed fish. Lampreys belong to the Cyclostomata, which includes the extant hagfish, and this group may have split early on from other agnathans.


  1. Parry, S. F.; Noble, S. R.; Crowley, Q. G.; Wellman, C. H. (2011). "A high-precision U–Pb age constraint on the Rhynie Chert Konservat-Lagerstätte: time scale and other implications". Journal of the Geological Society. London: Geological Society. 168 (4): 863–872. doi:10.1144/0016-76492010-043.
  2. Kaufmann, B.; Trapp, E.; Mezger, K. (2004). "The numerical age of the Upper Frasnian (Upper Devonian) Kellwasser horizons: A new U-Pb zircon date from Steinbruch Schmidt(Kellerwald, Germany)". The Journal of Geology. 112 (4): 495–501. Bibcode:2004JG....112..495K. doi:10.1086/421077.
  3. Algeo, T. J. (1998). "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events". Philosophical Transactions of the Royal Society B: Biological Sciences. 353 (1365): 113–130. doi:10.1098/rstb.1998.0195.
  4. "Chart/Time Scale". International Commission on Stratigraphy.
  5. Chlupáč, Ivo; Hladil, Jindrich (January 2000). "The global stratotype section and point of the Silurian-Devonian boundary". CFS Courier Forschungsinstitut Senckenberg: 1–8. Retrieved 7 December 2020.
  6. Kaiser, Sandra (1 April 2009). "The Devonian/Carboniferous boundary stratotype section (La Serre, France) revisited". Newsletters on Stratigraphy. 43 (2): 195–205. doi:10.1127/0078-0421/2009/0043-0195 . Retrieved 7 December 2020.
  7. Paproth, Eva; Feist, Raimund; Flajs, Gerd (December 1991). "Decision on the Devonian-Carboniferous boundary stratotype" (PDF). Episodes. 14 (4): 331–336. doi: 10.18814/epiiugs/1991/v14i4/004 .
  8. Haq, B. U.; Schutter, SR (2008). "A Chronology of Paleozoic Sea-Level Changes". Science. 322 (5898): 64–68. Bibcode:2008Sci...322...64H. doi:10.1126/science.1161648. PMID   18832639. S2CID   206514545.
  9. Wells, John (3 April 2008). Longman Pronunciation Dictionary (3rd ed.). Pearson Longman. ISBN   978-1-4058-8118-0.
  10. "Devonian". Unabridged (Online). n.d.
  11. Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. Cambridge: Cambridge University Press. ISBN   978-0521786737.
  12. Amos, Jonathan. "Fossil tracks record 'oldest land-walkers'". BBC News. Retrieved 24 December 2016.
  13. Newitz, Annalee (13 June 2013). "How do you have a mass extinction without an increase in extinctions?". The Atlantic.
  14. Gradstein, Ogg & Smith (2004)
  15. Rudwick, M.S.J. (1985). The great Devonian controversy: The shaping of scientific knowledge among gentlemanly specialists . Chicago: University of Chicago Press. ISBN   978-0226731025.
  16. Sedgwick, Adam; Murchison, Roderick Impey (1840). "On the physical structure of Devonshire, and on the subdivisions and geological relations of its older stratified deposits, etc. Part I and Part II". Transactions of the Geological Society of London. Second series. Vol. 5 part II. p. 701.
  17. Sedgwick & Murchison 1840, p. 690.
  18. Lonsdale, William (1840). "Notes on the age of limestones from south Devonshire". Transactions of the Geological Society of London. Second series. Vol. 5 part II. p. 724.
  19. Gradstein, Ogg & Smith 2004.
  20. Farabee, Michael J. (2006). "Paleobiology: The Late Paleozoic: Devonian". The Online Biology Book. Estrella Mountain Community College.
  21. Barclay, W.J. (1989). Geology of the South Wales Coalfield Part II, the country around Abergavenny. Memoir for 1:50,000 geological sheet (England and Wales) (3rd ed.). pp. 18–19. ISBN   0-11-884408-3.
  22. 1 2 Cohen, K.M.; Finney, S.C.; Gibbard, P.L.; Fan, J.-X. (2013). "The ICS International Chronostratigraphic Chart" (PDF). Episodes. 36 (3): 199–204. doi: 10.18814/epiiugs/2013/v36i3/002 . Retrieved 7 January 2021.
  23. Clack, Jennifer (13 August 2007). "Devonian climate change, breathing, and the origin of the tetrapod stem group". Integrative and Comparative Biology. 47 (4): 510–523. doi: 10.1093/icb/icm055 . PMID   21672860. Estimates of oxygen levels during this period suggest that they were unprecedentedly low during the Givetian and Frasnian periods. At the same time, plant diversification was at its most rapid, changing the character of the landscape and contributing, via soils, soluble nutrients, and decaying plant matter, to anoxia in all water systems. The co-occurrence of these global events may explain the evolution of air-breathing adaptations in at least two lobe-finned groups, contributing directly to the rise of the tetrapod stem group.
  24. 1 2 3 4 Joachimski, M. M.; Breisig, S.; Buggisch, W. F.; Talent, J. A.; Mawson, R.; Gereke, M.; Morrow, J. R.; Day, J.; Weddige, K. (July 2009). "Devonian climate and reef evolution: Insights from oxygen isotopes in apatite". Earth and Planetary Science Letters. 284 (3–4): 599–609. Bibcode:2009E&PSL.284..599J. doi:10.1016/j.epsl.2009.05.028.
  25. Rosa, Eduardo L. M.; Isbell, John L. (2021). "Late Paleozoic Glaciation". In Alderton, David; Elias, Scott A. (eds.). Encyclopedia of Geology (2nd ed.). Academic Press. pp. 534–545. doi:10.1016/B978-0-08-102908-4.00063-1. ISBN   978-0-08-102909-1.
  26. McClung, Wilson S.; Eriksson, Kenneth A.; Terry Jr., Dennis O.; Cuffey, Clifford A. (1 October 2013). "Sequence stratigraphic hierarchy of the Upper Devonian Foreknobs Formation, central Appalachian Basin, USA: Evidence for transitional greenhouse to icehouse conditions". Palaeogeography, Palaeoclimatology, Palaeoecology . 387: 104–125. doi:10.1016/j.palaeo.2013.07.020 . Retrieved 16 November 2022.
  27. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Cocks, L. Robin M.; Torsvik, Trond H., eds. (2016), "Devonian", Earth History and Palaeogeography, Cambridge: Cambridge University Press, pp. 138–158, doi:10.1017/9781316225523.009, ISBN   978-1-316-22552-3 , retrieved 24 July 2022
  28. 1 2 3 4 5 6 7 Golonka, Jan (1 March 2020). "Late Devonian paleogeography in the framework of global plate tectonics". Global and Planetary Change. 186: 103129. Bibcode:2020GPC...18603129G. doi:10.1016/j.gloplacha.2020.103129. ISSN   0921-8181. S2CID   212928195.
  29. "Devonian Period". Encyclopedia Britannica. geochronology. Retrieved 15 December 2017.
  30. Blakey, Ron C. "Devonian Paleogeography, Southwestern US". Northern Arizona University. Archived from the original on 15 April 2010.
  31. Hervé, Francisco; Calderón, Mauricio; Fanning, Mark; Pankhurst, Robert; Rapela, Carlos W.; Quezada, Paulo (2018). "The country rocks of Devonian magmatism in the North Patagonian Massif and Chaitenia". Andean Geology . 45 (3): 301–317. doi: 10.5027/andgeoV45n3-3117 .
  32. Franke, Wolfgang; Cocks, L. Robin M.; Torsvik, Trond H. (2017). "The Palaeozoic Variscan oceans revisited". Gondwana Research. 48: 257–284. Bibcode:2017GondR..48..257F. doi:10.1016/
  33. Benton, M. J. (2005). Vertebrate Palaeontology (3rd ed.). John Wiley. p. 14. ISBN   9781405144490.
  34. Nagel-Myers, Judith (5 August 2021). "An updated look at the taxonomy, stratigraphy, and palaeoecology of the Devonian bivalve genus Ontaria Clarke, 1904 (Cardiolidae, Bivalvia)". Palaeobiodiversity and Palaeoenvironments. 102: 541–555. doi:10.1007/s12549-021-00491-2 . Retrieved 8 November 2022.
  35. Kazlev, M. Alan (28 May 1998). "Palaeos Paleozoic: Devonian: The Devonian Period – 1". Palaeos. Retrieved 24 January 2019.
  36. Klug, Christian; Kroeger, Bjoern; Korn, Dieter; Ruecklin, Martin; Schemm-Gregory, Mena; De Baets, Kenneth; Mapes, Royal H. (April 2008). "Ecological change during the early Emsian (Devonian) in the Tafilalt (Morocco), the origin of the Ammonoidea, and the first African pyrgocystid edrioasteroids, machaerids and phyllocarids". Palaeontographica abteilung a-Palaozoologie-Stratigraphie. 283 (4–6): 83-U58. Retrieved 8 November 2022.
  37. Dalton, Rex (January 2006). "Hooked on fossils". Nature. 439 (7074): 262–263. doi:10.1038/439262a. PMID   16421540. S2CID   4357313.
  38. Klug, Christian; Kröger, Björn; Kiessling, Wolfgang; Mullins, Gary L.; Servais, Thomas; Frýda, Jiří; Korn, Dieter; Turner, Susan (26 October 2010). "The Devonian nekton revolution". Lethaia. 43 (4): 465–477. doi:10.1111/j.1502-3931.2009.00206.x . Retrieved 3 September 2022.
  39. Whalen, Christopher D.; Briggs, Derek E. G. (18 July 2018). "The Palaeozoic colonization of the water column and the rise of global nekton". Proceedings of the Royal Society B. 285 (1883): 1–9. doi:10.1098/rspb.2018.0883. PMC   6083262 . PMID   30051837.
  40. Tyler, Ian M.; Hocking, Roger M.; Haines, Peter W. (1 March 2012). "Geological evolution of the Kimberley region of Western Australia". Episodes. 35 (1): 298–306. doi: 10.18814/epiiugs/2012/v35i1/029 .
  41. Joachimski, M.M.; Breisig, S.; Buggisch, W.; Talent, J.A.; Mawson, R.; Gereke, M.; Morrow, J.R.; Day, J.; Weddige, K. (July 2009). "Devonian climate and reef evolution: Insights from oxygen isotopes in apatite". Earth and Planetary Science Letters. 284 (3–4): 599–609. Bibcode:2009E&PSL.284..599J. doi:10.1016/j.epsl.2009.05.028.
  42. Garwood, Russell J.; Dunlop, Jason (July 2014). "The walking dead: Blender as a tool for paleontologists with a case study on extinct arachnids". Journal of Paleontology . 88 (4): 735–746. doi:10.1666/13-088. ISSN   0022-3360. S2CID   131202472 . Retrieved 21 July 2015.
  43. Garwood, Russell J.; Edgecombe, Gregory D. (September 2011). "Early Terrestrial Animals, Evolution, and Uncertainty". Evolution: Education and Outreach. 4 (3): 489–501. doi: 10.1007/s12052-011-0357-y .
  44. Hueber, Francis M. (2001). "Rotted wood-alga fungus: The history and life of Prototaxites Dawson 1859". Review of Palaeobotany and Palynology. 116 (1–2): 123–159. doi:10.1016/s0034-6667(01)00058-6.
  45. Graham, Linda E.; Cook, Martha E.; Hanson, David T.; Pigg, Kathleen B.; Graham, James M. (2010). "Rolled liverwort mats explain major Prototaxites features: Response to commentaries". American Journal of Botany. 97 (7): 1079–1086. doi: 10.3732/ajb.1000172 . PMID   21616860.
  46. Taylor, Thomas N.; Taylor, Edith L.; Decombeix, Anne-Laure; Schwendemann, Andrew; Serbet, Rudolph; Escapa, Ignacio; Krings, Michael (2010). "The enigmatic Devonian fossil Prototaxites is not a rolled-up liverwort mat: Comment on the paper by Graham et al.(AJB 97: 268–275)". American Journal of Botany. 97 (7): 1074–1078. doi: 10.3732/ajb.1000047 . PMID   21616859.
  47. Niedźwiedzki (2010). "Tetrapod trackways from the early middle Devonian period of Poland". Nature . 463 (7277): 43–48. Bibcode:2010Natur.463...43N. doi:10.1038/nature08623. PMID   20054388. S2CID   4428903.
  48. Lucas (2015). "Thinopus and a Critical Review of Devonian Tetrapod Footprints". Ichnos . 22 (3–4): 136–154. doi:10.1080/10420940.2015.1063491. S2CID   130053031.
  49. Zhang, Ying-ying; Xue, Jin-Zhuang; Liu, Le; Wang, De-ming (2016). "Periodicity of reproductive growth in lycopsids: An example from the Upper Devonian of Zhejiang Province, China". Paleoworld. 25 (1): 12–20. doi:10.1016/j.palwor.2015.07.002.
  50. Gonez, Paul; Gerrienne, Philippe (2010). "A new definition and a lectotypification of the genus Cooksonia Lang 1937". International Journal of Plant Sciences. 171 (2): 199–215. doi:10.1086/648988. S2CID   84956576.
  51. MacPherson, C. (28 August 2019). "Analyzing the World's Oldest Woody Plant Fossil". Canadian Light Source . Retrieved 19 May 2021.
  52. Smith, Lewis (19 April 2007). "Fossil from a forest that gave Earth its breath of fresh air". The Times. London. Retrieved 1 May 2010.
  53. Hogan, C. Michael (2010). "Fern". In Basu, Saikat; Cleveland, C. (eds.). Encyclopedia of Earth. Washington DC: National Council for Science and the Environment.
  54. Weng, Jing-Ke; Chapple, Clint (July 2010). "The origin and evolution of lignin biosynthesis: Tansley review". New Phytologist. 187 (2): 273–285. doi: 10.1111/j.1469-8137.2010.03327.x . PMID   20642725.
  55. Capel, Elliot; Cleal, Christopher J.; Xue, Jinzhuang; Monnet, Claude; Servais, Thomas; Cascales-Miñana, Borja (August 2022). "The Silurian–Devonian terrestrial revolution: Diversity patterns and sampling bias of the vascular plant macrofossil record". Earth-Science Reviews . 231. doi:10.1016/j.earscirev.2022.104085 . Retrieved 8 November 2022.
  56. Gess, R.W. (2013). "The earliest record of terrestrial animals in Gondwana: A scorpion from the Famennian (Late Devonian) Witpoort Formation of South Africa". African Invertebrates . 54 (2): 373–379. doi: 10.5733/afin.054.0206 .
  57. 1 2 Becker, R. T.; Marshall, J. E. A.; Da Silva, A. -C.; Agterberg, F. P.; Gradstein, F. M.; Ogg, J. G. (1 January 2020), Gradstein, Felix M.; Ogg, James G.; Schmitz, Mark D.; Ogg, Gabi M. (eds.), "Chapter 22 - The Devonian Period", Geologic Time Scale 2020, Elsevier, pp. 733–810, doi:10.1016/b978-0-12-824360-2.00022-x, ISBN   978-0-12-824360-2, S2CID   241766371 , retrieved 19 March 2021
  58. Raup, D. M.; Sepkoski, J. J. (19 March 1982). "Mass Extinctions in the Marine Fossil Record". Science. 215 (4539): 1501–1503. Bibcode:1982Sci...215.1501R. doi:10.1126/science.215.4539.1501. ISSN   0036-8075. PMID   17788674. S2CID   43002817.
  59. McGhee, George R. (1996). The Late Devonian mass extinction : the Frasnian/Famennian crisis. New York: Columbia University Press. ISBN   0-231-07504-9. OCLC   33010274.
  60. After a Mass Extinction, Only the Small Survive | Carl Zimmer
  61. McGhee, George R. (2013). When the invasion of land failed: The legacy of the Devonian extinctions. New York: Columbia University Press. ISBN   9780231160568.
  62. Carmichael, Sarah K.; Waters, Johnny A.; Königshof, Peter; Suttner, Thomas J.; Kido, Erika (1 December 2019). "Paleogeography and paleoenvironments of the Late Devonian Kellwasser event: A review of its sedimentological and geochemical expression". Global and Planetary Change. 183: 102984. Bibcode:2019GPC...18302984C. doi:10.1016/j.gloplacha.2019.102984. ISSN   0921-8181. S2CID   198415606.
  63. Lu, Man; Lu, YueHan; Ikejiri, Takehitio; Sun, Dayang; Carroll, Richard; Blair, Elliot H.; Algeo, Thomas J.; Sun, Yongge (15 May 2021). "Periodic oceanic euxinia and terrestrial fluxes linked to astronomical forcing during the Late Devonian Frasnian–Famennian mass extinction". Earth and Planetary Science Letters. 562: 116839. Bibcode:2021E&PSL.56216839L. doi:10.1016/j.epsl.2021.116839. ISSN   0012-821X. S2CID   233578058.
  64. Kaiser, Sandra Isabella; Aretz, Markus; Becker, Ralph Thomas (11 November 2015). "The global Hangenberg Crisis (Devonian–Carboniferous transition): review of a first-order mass extinction". Geological Society, London, Special Publications. 423 (1): 387–437. doi:10.1144/sp423.9. ISSN   0305-8719. S2CID   131270834.
  65. Racki, Grzegorz (1 January 2005), Over, D. J.; Morrow, J. R.; Wignall, P. B. (eds.), "Chapter 2Toward understanding Late Devonian global events: few answers, many questions", Developments in Palaeontology and Stratigraphy, Understanding Late Devonian And Permian-Triassic Biotic and Climatic Events, Elsevier, vol. 20, pp. 5–36, doi:10.1016/s0920-5446(05)80002-0, ISBN   9780444521279 , retrieved 19 March 2021
  66. Rendall; Tapanila (2020). "Impact resilience: Ecological recovery of a carbonate factory in the wake of the Late Devonian impact event". PALAIOS. 35 (1): 12–21. Bibcode:2020Palai..35...12R. doi:10.2110/palo.2019.001. S2CID   210944155.