Carboniferous

• 石炭紀の

関

Carboniferous period

　 　

WordNet

1. from 345 million to 280 million years ago (同)Carboniferous_period
2. of or relating to the Carboniferous geologic era; "carboniferous rock system"

PrepTutorEJDIC

1. (地質時代の)石炭紀の / 《carboniferous》石炭を生じる / 石炭紀(系)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/01/08 13:37:39」(JST)

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地質時代区分

顕生代	新生代	第四紀
		新第三紀
		古第三紀
	中生代	白亜紀
		ジュラ紀
		三畳紀
	古生代	ペルム紀
		石炭紀
		デボン紀
		シルル紀
		オルドビス紀
		カンブリア紀
原生代
始生代
冥王代

石炭紀（せきたんき、Carboniferous period）は、地質時代の区分のひとつ。古生代の後半で、デボン紀の後、ペルム紀の前の時代を指し、これはおおよそ現在より3億5920万年前から2億9900万年前までの時期にあたる。この期間はデボン紀末の大量絶滅からペルム紀直前の数百万年に及ぶ氷河期で区切られている。

名前の由来はこの時代の地層から多く石炭を産することによる。この地層から石炭を産するのは当時非常に大きな森林が形成されていたことの傍証となる。

北米では石炭紀の前半をミシシッピ紀（Mississippian）、後半をペンシルベニア紀 (Pennsylvanian) と呼ぶ研究者もいる。これらはおおよそ3億2300万年前よりも前か後かで分けられる。

北サマセットでは、石炭層をコールメジャーズと呼び、上部、中部、下部に分けている。この層は古生代の終わりの2000万年の間に堆積したと考えられており、放射性炭素年代測定でおよそ3億1000万年前から2億9000年前のものとされている。。

生物

陸上では、シダ植物が発達し、昆虫や両生類が栄えた。この時代、両生類から陸上生活に適応した有羊膜類が出現し、やがて二つの大きなグループが分岐した。竜弓類（鳥類を含む爬虫類へとつながる系統）と単弓類（哺乳類へと繋がる系統）である。当時の爬虫類ではヒロノムスなどが知られている。また、パレオディクティオプテラやゴキブリの祖先プロトファスマなど翅を持った昆虫が初めて出現した。これらは史上初めて空へ進出した生物である。

デボン紀から引き続いて節足動物、昆虫の巨大化も著しく、全長60cmもある巨大なウミサソリ（メガラシネ）や翼長70cmの巨大トンボ（メガネウラ）、全長2mの巨大ムカデ（アースロプレウラ）などが発見されている。これらの節足動物は陸上進出を果たした両生類や有羊膜類の貴重な蛋白源になったといわれている。逆に三葉虫は衰えてプロエトゥス目（またはプロエタス目）のみとなった。末期には数百万年に渡る氷河期が到来し多くの生物が死滅した。

巨大なシダ類が繁栄し、中でもリンボク（レピドデンドロン）は大きいもので直径2m、高さ38mのものが存在し、このような巨大なシダ類が湿地帯に大森林を形成していた。これらの巨木は標準的なものでも20m〜30mの高さがあった。

アメリカのイリノイ州には石炭紀の無脊椎動物の化石を多く出土する地層があり、ここから出土する動物群を特にメゾンクリーク動物群と呼ぶ。メゾンクリーク動物群には腕足類やウミユリなどが多く含まれ、トリモンストラム・グレガリウム（トゥリモンストゥルム）など異様な形態の動物も見受けられる。

後期にはエダフォサウルスなどの単弓類（哺乳類型爬虫類）が繁栄していく。

環境

多くの地域は年間を通して季節の変化はあまりなく、1年中湿潤な熱帯気候であったといわれる。一方で南極では氷河が形成されるなど、寒冷化が進行しつつあった。森林の繁栄により、大気中の酸素濃度は35%に達したといわれる（現代は21%）。このことが動植物の大型化を可能にしたと考えられている。また、植物が繁栄したことで大量の二酸化炭素が吸収され、その多くが大気中に還元されずに石炭化していったため、大気中の二酸化炭素濃度が激減した。これが寒冷化と氷河の発達、ひいては氷河期の一因とされる。

巨大な陸塊であるゴンドワナ大陸の南部が南極にあったこともあり、ここには大規模な氷河（氷床）が形成されていき、終盤に氷河期が訪れた。

地質

地質的にはバリスカン造山運動の活動期に当たる。デボン紀から存在していたライク海（リーク海、レーイック海またはミドローピアン海とも呼ぶ）はゴンドワナ大陸とユーラメリカ大陸にはさまれて末期には消滅し、これがやがて次の時代のパンゲア大陸となる。ライク海の消滅と歩調をあわせるかのように生物の陸上新出も進んだ。

この他にもシベリア大陸、カザフ大陸（カザフスタニア）などの小さな大陸が存在していた。

脚注

参考文献

関連項目

• 地質時代 - 顕生代 - 古生代

外部リンク

• 仲田崇志 (2009年10月29日). “地質年代表”. きまぐれ生物学. 2011年2月14日閲覧。

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For the album, see Carboniferous (album).

Carboniferous Period 358.9–298.9 million years ago PreЄ Є O S D C P T J K Pg N
Mean atmospheric O 2 content over period duration	ca. 32.5 Vol % (163 % of modern level)
Mean atmospheric CO 2 content over period duration	ca. 800 ppm (3 times pre-industrial level)
Mean surface temperature over period duration	ca. 14 °C (0 °C above modern level)
Sea level (above present day)	Falling from 120m to present day level throughout Mississippian, then rising steadily to about 80m at end of period
Key events in the Carboniferous view • discuss •  -360 — – -355 — – -350 — – -345 — – -340 — – -335 — – -330 — – -325 — – -320 — – -315 — – -310 — – -305 — – -300 — – -295 — P a l e o z o i c Devonian   Permian     Tournaisian Viséan Serpukhovian Bashkirian Moscovian Kasimovian Gzhelian             ← Carboniferous Rainforest Collapse ← Essex and Braidwood fauna ← End of Romer's Gap ← Start of Romer's Gap C a r b o n i f e r o u s M i s s - i a n P e - i a n Key events of the Carboniferous Period. Axis scale: millions of years ago.

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 358.9 ± 0.4 million years ago, to the beginning of the Permian Period, about 298.9 ± 0.15 Ma. The name Carboniferous means "coal-bearing" and derives from the Latin words carbo (coal) and fero, fers (to carry), and was coined by geologists William Conybeare and William Phillips in 1822. Based on a study of the British rock succession, it was the first of the modern 'system' names to be employed, and reflects the fact that many coal beds were formed globally during this time. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian.

Terrestrial life was well established by the Carboniferous period. Amphibians were the dominant land vertebrates, of which one branch would eventually evolve into reptiles, the first fully terrestrial vertebrates. Arthropods were also very common, and many (such as Meganeura), were much larger than those of today. Vast swaths of forest covered the land, which would eventually be laid down and become the coal beds characteristic of the Carboniferous system. A minor marine and terrestrial extinction event occurred in the middle of the period, caused by a change in climate. The later half of the period experienced glaciations, low sea level, and mountain building as the continents collided to form Pangaea.

Subdivisions

In the United States the Carboniferous is usually broken into Mississippian (earlier) and Pennsylvanian (later) Periods. The Mississippian is about twice as long as the Pennsylvanian, but due to the large thickness of coal bearing deposits with Pennsylvanian ages in Europe and North America, the two subperiods were long thought to have been more or less equal. The faunal stages from youngest to oldest, together with some of their subdivisions, are:

Late Pennsylvanian: Gzhelian (most recent)

• Noginskian / Virgilian (part)

Late Pennsylvanian: Kasimovian

• Klazminskian
• Dorogomilovksian / Virgilian (part)
• Chamovnicheskian / Cantabrian / Missourian
• Krevyakinskian / Cantabrian / Missourian

Middle Pennsylvanian: Moscovian

• Myachkovskian / Bolsovian / Desmoinesian
• Podolskian / Desmoinesian
• Kashirskian / Atokan
• Vereiskian / Bolsovian / Atokan

Early Pennsylvanian: Bashkirian / Morrowan

• Melekesskian / Duckmantian
• Cheremshanskian / Langsettian
• Yeadonian
• Marsdenian
• Kinderscoutian

Late Mississippian: Serpukhovian

• Alportian
• Chokierian / Chesterian / Elvirian
• Arnsbergian / Elvirian
• Pendleian

Middle Mississippian: Visean

• Brigantian / St Genevieve / Gasperian / Chesterian
• Asbian / Meramecian
• Holkerian / Salem
• Arundian / Warsaw / Meramecian
• Chadian / Keokuk / Osagean (part) / Osage (part)

Early Mississippian: Tournaisian (oldest)

• Ivorian / (part) / Osage (part)
• Hastarian / Kinderhookian / Chouteau

Paleogeography

A global drop in sea level at the end of the Devonian reversed early in the Carboniferous; this created the widespread epicontinental seas and carbonate deposition of the Mississippian. There was also a drop in south polar temperatures; southern Gondwanaland was glaciated throughout the period, though it is uncertain if the ice sheets were a holdover from the Devonian or not. These conditions apparently had little effect in the deep tropics, where lush coal swamps flourished within 30 degrees of the northernmost glaciers.

Generalized geographic map of the United States in Middle Pennsylvanian time.

A mid-Carboniferous drop in sea level precipitated a major marine extinction, one that hit crinoids and ammonites especially hard. This sea level drop and the associated unconformity in North America separate the Mississippian subperiod from the Pennsylvanian subperiod. This happened about 318 million years ago, at the onset of the Permo-Carboniferous Glaciation.^{[citation needed]}

The Carboniferous was a time of active mountain-building, as the supercontinent Pangaea came together. The southern continents remained tied together in the supercontinent Gondwana, which collided with North America–Europe (Laurussia) along the present line of eastern North America. This continental collision resulted in the Hercynian orogeny in Europe, and the Alleghenian orogeny in North America; it also extended the newly uplifted Appalachians southwestward as the Ouachita Mountains. In the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural mountains. Most of the Mesozoic supercontinent of Pangea was now assembled, although North China (which would collide in the Latest Carboniferous), and South China continents were still separated from Laurasia. The Late Carboniferous Pangaea was shaped like an "O."

There were two major oceans in the Carboniferous—Panthalassa and Paleo-Tethys, which was inside the "O" in the Carboniferous Pangaea. Other minor oceans were shrinking and eventually closed - Rheic Ocean (closed by the assembly of South and North America), the small, shallow Ural Ocean (which was closed by the collision of Baltica and Siberia continents, creating the Ural Mountains) and Proto-Tethys Ocean (closed by North China collision with Siberia/Kazakhstania).

Climate

The early part of the Carboniferous was mostly warm; in the later part of the Carboniferous, the climate cooled. Glaciations in Gondwana, triggered by Gondwana's southward movement, continued into the Permian and because of the lack of clear markers and breaks, the deposits of this glacial period are often referred to as Permo-Carboniferous in age.

The cooling and drying of the climate led to the Carboniferous Rainforest Collapse (CRC). Tropical rainforests fragmented and then were eventually devastated by climate change.

Rocks and coal

Lower Carboniferous marble in Big Cottonwood Canyon, Wasatch Mountains, Utah.

Carboniferous rocks in Europe and eastern North America largely consist of a repeated sequence of limestone, sandstone, shale and coal beds. In North America, the early Carboniferous is largely marine limestone, which accounts for the division of the Carboniferous into two periods in North American schemes. The Carboniferous coal beds provided much of the fuel for power generation during the Industrial Revolution and are still of great economic importance.

The large coal deposits of the Carboniferous primarily owe their existence to two factors. The first of these is the appearance of bark-bearing trees (and in particular the evolution of the bark fiber lignin). The second is the lower sea levels that occurred during the Carboniferous as compared to the Devonian period. This allowed for the development of extensive lowland swamps and forests in North America and Europe. Based on a genetic analysis of mushroom fungi, David Hibbett and colleagues proposed that large quantities of wood were buried during this period because animals and decomposing bacteria had not yet evolved that could effectively digest the tough lignin. It is assumed that fungi that could break it down did not arise before the end of the period, making future coal formation much more rare. The Carboniferous trees made extensive use of lignin. They had bark to wood ratios of 8 to 1, and even as high as 20 to 1. This compares to modern values less than 1 to 4. This bark, which must have been used as support as well as protection, probably had 38% to 58% lignin. Lignin is insoluble, too large to pass through cell walls, too heterogeneous for specific enzymes, and toxic, so that few organisms other than Basidiomycetes fungi can degrade it. It can not be oxidized in an atmosphere of less than 5% oxygen. It can linger in soil for thousands of years and inhibits decay of other substances. Probably the reason for its high percentages is protection from insect herbivory in a world containing very effective insect herbivores, but nothing remotely as effective as modern insectivores and probably many fewer poisons than currently. In any case coal measures could easily have made thick deposits on well drained soils as well as swamps. The extensive burial of biologically produced carbon led to a buildup of surplus oxygen in the atmosphere; estimates place the peak oxygen content as high as 35%, compared to 21% today.[1] This oxygen level probably increased wildfire activity, as well as resulted in insect and amphibian gigantism—creatures whose size is constrained by respiratory systems that are limited in their ability to diffuse oxygen

In eastern North America, marine beds are more common in the older part of the period than the later part and are almost entirely absent by the late Carboniferous. More diverse geology existed elsewhere, of course. Marine life is especially rich in crinoids and other echinoderms. Brachiopods were abundant. Trilobites became quite uncommon. On land, large and diverse plant populations existed. Land vertebrates included large amphibians.

Life

Plants

Etching depicting some of the most significant plants of the Carboniferous.

Early Carboniferous land plants, some of which were preserved in coal balls, were very similar to those of the preceding Late Devonian, but new groups also appeared at this time.

The main Early Carboniferous plants were the Equisetales (horse-tails), Sphenophyllales (vine-like plants), Lycopodiales (club mosses), Lepidodendrales (scale trees), Filicales (ferns), Medullosales (informally included in the "seed ferns", an artificial assemblage of a number of early gymnosperm groups) and the Cordaitales. These continued to dominate throughout the period, but during late Carboniferous, several other groups, Cycadophyta (cycads), the Callistophytales (another group of "seed ferns"), and the Voltziales (related to and sometimes included under the conifers), appeared.

The Carboniferous lycophytes of the order Lepidodendrales, which are cousins (but not ancestors) of the tiny club-moss of today, were huge trees with trunks 30 meters high and up to 1.5 meters in diameter. These included Lepidodendron (with its fruit cone called Lepidostrobus), Halonia, Lepidophloios and Sigillaria. The roots of several of these forms are known as Stigmaria. Unlike present day trees, their secondary growth took place in the cortex, which also provided stability, instead of the xylem. The Cladoxylopsids were large trees, that were ancestors of ferns, first arising in the Carboniferous.

The fronds of some Carboniferous ferns are almost identical with those of living species. Probably many species were epiphytic. Fossil ferns and "seed ferns" include Pecopteris, Cyclopteris, Neuropteris, Alethopteris, and Sphenopteris; Megaphyton and Caulopteris were tree ferns.

The Equisetales included the common giant form Calamites, with a trunk diameter of 30 to 60 cm (24 in) and a height of up to 20 m (66 ft). Sphenophyllum was a slender climbing plant with whorls of leaves, which was probably related both to the calamites and the lycopods.

Cordaites, a tall plant (6 to over 30 meters) with strap-like leaves, was related to the cycads and conifers; the catkin-like inflorescence, which bore yew-like berries, is called Cardiocarpus. These plants were thought to live in swamps and mangroves. True coniferous trees (Walchia, of the order Voltziales) appear later in the Carboniferous, and preferred higher drier ground.

• Ancient in situ lycopsid, probably Sigillaria, with attached stigmarian roots.

• Base of a lycopsid showing connection with bifurcating stigmarian roots.

Marine invertebrates

In the oceans the most important marine invertebrate groups are the Foraminifera, corals, Bryozoa, Ostracoda, brachiopods, ammonoids, hederelloids, microconchids and echinoderms (especially crinoids). For the first time foraminifera take a prominent part in the marine faunas. The large spindle-shaped genus Fusulina and its relatives were abundant in what is now Russia, China, Japan, North America; other important genera include Valvulina, Endothyra, Archaediscus, and Saccammina (the latter common in Britain and Belgium). Some Carboniferous genera are still extant.

The microscopic shells of radiolarians are found in cherts of this age in the Culm of Devon and Cornwall, and in Russia, Germany and elsewhere. Sponges are known from spicules and anchor ropes, and include various forms such as the Calcispongea Cotyliscus and Girtycoelia, the demosponge Chaetetes, and the genus of unusual colonial glass sponges Titusvillia.

Both reef-building and solitary corals diversify and flourish; these include both rugose (for example, Caninia, Corwenia, Neozaphrentis), heterocorals, and tabulate (for example, Chladochonus, Michelinia) forms. Conularids were well represented by Conularia

Bryozoa are abundant in some regions; the fenestellids including Fenestella, Polypora, and Archimedes, so named because it is in the shape of an Archimedean screw. Brachiopods are also abundant; they include productids, some of which (for example, Gigantoproductus) reached very large (for brachiopods) size and had very thick shells, while others like Chonetes were more conservative in form. Athyridids, spiriferids, rhynchonellids, and terebratulids are also very common. Inarticulate forms include Discina and Crania. Some species and genera had a very wide distribution with only minor variations.

Annelids such as Serpulites are common fossils in some horizons. Among the mollusca, the bivalves continue to increase in numbers and importance. Typical genera include Aviculopecten, Posidonomya, Nucula, Carbonicola, Edmondia, and Modiola Gastropods are also numerous, including the genera Murchisonia, Euomphalus, Naticopsis. Nautiloid cephalopods are represented by tightly coiled nautilids, with straight-shelled and curved-shelled forms becoming increasingly rare. Goniatite ammonoids are common.

Trilobites are rarer than in previous periods, on a steady trend towards extinction, represented only by the proetid group. Ostracoda, a class of crustaceans, were abundant as representatives of the meiobenthos; genera included Amphissites, Bairdia, Beyrichiopsis, Cavellina, Coryellina, Cribroconcha, Hollinella, Kirkbya, Knoxiella, and Libumella.

Amongst the echinoderms, the crinoids were the most numerous. Dense submarine thickets of long-stemmed crinoids appear to have flourished in shallow seas, and their remains were consolidated into thick beds of rock. Prominent genera include Cyathocrinus, Woodocrinus, and Actinocrinus. Echinoids such as Archaeocidaris and Palaeechinus were also present. The blastoids, which included the Pentreinitidae and Codasteridae and superficially resembled crinoids in the possession of long stalks attached to the seabed, attain their maximum development at this time.

• Aviculopecten subcardiformis; a bivalve from the Logan Formation (Lower Carboniferous) of Wooster, Ohio (external mold).

• Bivalves (Aviculopecten) and brachiopods (Syringothyris) in the Logan Formation (Lower Carboniferous) in Wooster, Ohio.

• Syringothyris sp.; a spiriferid brachiopod from the Logan Formation (Lower Carboniferous) of Wooster, Ohio (internal mold).

• Palaeophycus ichnosp.; a trace fossil from the Logan Formation (Lower Carboniferous) of Wooster, Ohio.

• Crinoid calyx from the Lower Carboniferous of Ohio with a conical platyceratid gastropod (Palaeocapulus acutirostre) attached.

• Conulariid from the Lower Carboniferous of Indiana; scale in mm.

• Tabulate coral (a syringoporid); Boone Limestone (Lower Carboniferous) near Hiwasse, Arkansas. Scale bar is 2.0 cm (1 in).

Freshwater and lagoonal invertebrates

Freshwater Carboniferous invertebrates include various bivalve molluscs that lived in brackish or fresh water, such as Anthraconaia, Naiadites, and Carbonicola; diverse crustaceans such as Candona, Carbonita, Darwinula, Estheria, Acanthocaris, Dithyrocaris, and Anthrapalaemon.

The Eurypterids were also diverse, and are represented by such genera as Eurypterus, Glyptoscorpius, Anthraconectes, Megarachne (originally misinterpreted as a giant spider) and the specialised very large Hibbertopterus. Many of these were amphibious.

Frequently a temporary return of marine conditions resulted in marine or brackish water genera such as Lingula, Orbiculoidea, and Productus being found in the thin beds known as marine bands.

• The upper Carboniferous giant spider-like eurypterid Megarachne grew to legspans of 50 cm (20 in).

Terrestrial invertebrates

Fossil remains of air-breathing insects, myriapods and arachnids are known from the late Carboniferous, but so far not from the early Carboniferous. The first true priapulids appeared during this period. Their diversity when they do appear, however, shows that these arthropods were both well developed and numerous. Their large size can be attributed to the moistness of the environment (mostly swampy fern forests) and the fact that the oxygen concentration in the Earth's atmosphere in the Carboniferous was much higher than today (35% then compared with 21% today). This required less effort for respiration and allowed arthropods to grow larger with the up to 2.6 metres long millipede-like Arthropleura being the largest known land invertebrate of all time. Among the insect groups are the huge predatory Protodonata (griffinflies), among which was Meganeura, a giant dragonfly-like insect and with a wingspan of ca. 75 cm (30 in) — the largest flying insect ever to roam the planet. Further groups are the Syntonopterodea (relatives of present-day mayflies), the abundant and often large sap-sucking Palaeodictyopteroidea, the diverse herbivorous Protorthoptera, and numerous basal Dictyoptera (ancestors of cockroaches). Many insects have been obtained from the coalfields of Saarbrücken and Commentry, and from the hollow trunks of fossil trees in Nova Scotia. Some British coalfields have yielded good specimens: Archaeoptitus, from the Derbyshire coalfield, had a spread of wing extending to more than 35 cm; some specimens (Brodia) still exhibit traces of brilliant wing colors. In the Nova Scotian tree trunks land snails (Archaeozonites, Dendropupa) have been found.

• The late Carboniferous giant dragonfly-like insect Meganeura grew to wingspans of 75 cm (30 in).

• The gigantic Pulmonoscorpius from the early Carboniferous reached a length of up to 70 cm (28 in).

• The Arthropleura, the largest land arthropod of all time.

Fish

Many fish inhabited the Carboniferous seas; predominantly Elasmobranchs (sharks and their relatives). These included some, like Psammodus, with crushing pavement-like teeth adapted for grinding the shells of brachiopods, crustaceans, and other marine organisms. Other sharks had piercing teeth, such as the Symmoriida; some, the petalodonts, had peculiar cycloid cutting teeth. Most of the sharks were marine, but the Xenacanthida invaded fresh waters of the coal swamps. Among the bony fish, the Palaeonisciformes found in coastal waters also appear to have migrated to rivers. Sarcopterygian fish were also prominent, and one group, the Rhizodonts, reached very large size.

Most species of Carboniferous marine fish have been described largely from teeth, fin spines and dermal ossicles, with smaller freshwater fish preserved whole.

Freshwater fish were abundant, and include the genera Ctenodus, Uronemus, Acanthodes, Cheirodus, and Gyracanthus.

Sharks (especially the Stethacanthids) underwent a major evolutionary radiation during the Carboniferous. It is believed that this evolutionary radiation occurred because the decline of the placoderms at the end of the Devonian period caused many environmental niches to become unoccupied and allowed new organisms to evolve and fill these niches. As a result of the evolutionary radiation carboniferous sharks assumed a wide variety of bizarre shapes including Stethacanthus which possessed a flat brush-like dorsal fin with a patch of denticles on its top. Stethacanthus' unusual fin may have been used in mating rituals.

• Akmonistion of the shark order Symmoriida roamed the oceans of the early Carboniferous.

• Falcatus was a Carboniferous shark, with a high degree of sexual dimorphism.

Tetrapods

Carboniferous amphibians were diverse and common by the middle of the period, more so than they are today; some were as long as 6 meters, and those fully terrestrial as adults had scaly skin. They included a number of basal tetrapod groups classified in early books under the Labyrinthodontia. These had long bodies, a head covered with bony plates and generally weak or undeveloped limbs. The largest were over 2 meters long. They were accompanied by an assemblage of smaller amphibians included under the Lepospondyli, often only about 15 cm (6 in) long. Some Carboniferous amphibians were aquatic and lived in rivers (Loxomma, Eogyrinus, Proterogyrinus); others may have been semi-aquatic (Ophiderpeton, Amphibamus, Hyloplesion) or terrestrial (Dendrerpeton, Tuditanus, Anthracosaurus).

The Carboniferous Rainforest Collapse slowed the evolution of amphibians who could not survive as well in the cooler, drier conditions. Reptiles, however prospered due to specific key adaptations. One of the greatest evolutionary innovations of the Carboniferous was the amniote egg, which allowed for the further exploitation of the land by certain tetrapods. These included the earliest sauropsid reptiles (Hylonomus), and the earliest known synapsid (Archaeothyris). These small lizard-like animals quickly gave rise to many descendants. The amniote egg allowed these ancestors of all later birds, mammals, and reptiles to reproduce on land by preventing the desiccation, or drying-out, of the embryo inside.

Reptiles underwent a major evolutionary radiation in response to the drier climate that proceeded the rainforest collapse. By the end of the Carboniferous period, amniotes had already diversified into a number of groups, including protorothyridids, captorhinids, aeroscelids, and several families of pelycosaurs.

• The amphibian-like Pederpes, the most primitive Mississippian tetrapod

• Hylonomus, the earliest sauropsid reptile, appeared in the Pennsylvanian.

• Petrolacosaurus, the first diapsid reptile known, lived during the late Carboniferous.

• Archaeothyris was a very early mammal-like reptile and is the oldest undisputed synapsid known.

Fungi

Because plants and animals were growing in size and abundance in this time (for example, Lepidodendron), land fungi diversified further. Marine fungi still occupied the oceans. All modern classes of fungi were present in the Late Carboniferous (Pennsylvanian Epoch).

Extinction events

Romer's gap

Main article: Romer's gap

The first 15 million years of the Carboniferous had very limited terrestrial fossils. This gap in the fossil record is called Romer's gap after the American palaentologist Alfred Romer. While it has long been debated whether the gap is a result of fossilisation or relates to an actual event, recent work indicates the gap period saw a drop in atmospheric oxygen levels, indicating some sort of ecological collapse. The gap saw the demise of the Devonian fish-like ichthyostegalian labyrinthodonts, and the rise of the more advanced temnospondyl and reptiliomorphan amphibians that so typify the Carboniferous terrestrial vertebrate fauna.

Carboniferous rainforest collapse

Main article: Carboniferous Rainforest Collapse

Before the end of the Carboniferous Period, an extinction event occurred. On land this event is referred to as the Carboniferous Rainforest Collapse (CRC). Vast tropical rainforests collapsed suddenly as the climate changed from hot and humid to cool and arid. This was likely caused by intense glaciation and a drop in sea levels.

The new climatic conditions were not favorable to the growth of rainforest and the animals within them. Rainforests shrank into isolated islands, surrounded by seasonally dry habitats. Towering lycopsid forests with a heterogenous mixture of vegetation were replaced by much less diverse tree-fern dominated flora.

Amphibians, the dominant vertebrates at the time, fared poorly through this event with large losses in biodiversity; reptiles continued to diversify due to key adaptations that let them survive in the drier habitat, specifically the hard-shelled egg and scales both of which retain water better than their amphibian counterparts.

See also

• Carboniferous tetrapods
• Important Carboniferous Lagerstätten
  • East Kirkton Quarry; c. 350 mya; Bathgate, Scotland
  • Hamilton Quarry; 320 mya; Kansas, US
  • Mazon Creek; 300 mya; Illinois, US
• List of fossil sites (with link directory)

References

Further reading

• Dudley, Robert (1998). "Atmospheric Oxygen, Giant Paleozoic Insects and the Evolution of Aerial Locomotor Performance". Journal of Experimental Biology 201: 1043–1050. 
• Menning, M.; Alekseev, A.S.; Chuvashov, B.I.; Davydov, V.I.; Devuyst, F.-X.; Forke, H.C.; Grunt, T.A.; Hance, L.; Heckel, P.H.; Izokh, N.G.; Jin, Y.-G.; Jones, P.J.; Kotlyar, G.V.; Kozur, H.W.; Nemyrovska, T.I.; Schneider, J.W.; Wang, X.-D.; Weddige, K.; Weyer, D. & Work, D.M. (2006). "Global time scale and regional stratigraphic reference scales of Central and West Europe, East Europe, Tethys, South China, and North America as used in the Devonian–Carboniferous–Permian Correlation Chart 2003 (DCP 2003)". Palaeogeography, Palaeoclimatology, Palaeoecology 240 (1-2): 318–372. 
• Ogg, Jim (June 2004). "Overview of Global Boundary Stratotype Sections and Points (GSSP's)". Retrieved April 30, 2006. 
• Stanley, S.M. (1999). Earth System History. New York: W.H. Freeman and Company. ISBN 0-7167-2882-6. 

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press 

External links

• "Geologic Time Scale 2004". International Commission on Stratigraphy (ICS). Retrieved January 15, 2013. 
• Examples of Carboniferous Fossils
• 60+ images of Carboniferous Foraminifera

Preceded by Proterozoic Eon	Phanerozoic Eon
	Paleozoic Era						Mesozoic Era			Cenozoic Era
	Cambrian	Ordovician	Silurian	Devonian	Carboniferous	Permian	Triassic	Jurassic	Cretaceous	Paleogene	Neogene	Quaternary

English Journal

• An Eocene orthocone from Antarctica shows convergent evolution of internally shelled cephalopods.

• Doguzhaeva LA1, Bengtson S1, Reguero MA2, Mörs T1.
• PloS one.PLoS One.2017 Mar 1;12(3):e0172169. doi: 10.1371/journal.pone.0172169. eCollection 2017.
• PMID 28248970

• Paleozoic Nymphal Wing Pads Support Dual Model of Insect Wing Origins.

• Prokop J1, Pecharová M2, Nel A3, Hörnschemeyer T4, Krzemińska E5, Krzemiński W6, Engel MS7.
• Current biology : CB.Curr Biol.2017 Jan 23;27(2):263-269. doi: 10.1016/j.cub.2016.11.021. Epub 2017 Jan 12.
• PMID 28089512

• Did trees grow up to the light, up to the wind, or down to the water? How modern high productivity colors perception of early plant evolution.

• Boyce CK1, Fan Y2, Zwieniecki MA3.
• The New phytologist.New Phytol.2017 Jan 5. doi: 10.1111/nph.14387. [Epub ahead of print]
• PMID 28054354

Japanese Journal

• (2)研究科特別経費(学生分)研究成果報告 : 揚子炭酸塩プラットフォーム,石炭系堆積盆の発達過程と有孔虫群集変遷

• 星木 勇作
• 福岡大学理学集報 45(1), 87-88, 2015-03
• NAID 110009889224

• Early Carboniferous nautiloids from the Ruddell Shale Member in Arkansas, Midcontinent North America

• NIKO SHUJI,MAPES ROYAL H.
• Paleontological Research 19(1), 52-60, 2015-01
• NAID 40020320774

• Geochemical characteristics of the Late Devonian to Early Carboniferous cherts from Loei Fold Belt in NE Thailand : implication for geotectonic setting

• Zhao Tianyu,Feng Qinglai,Qian Xin
• Science reports of Niigata University. (Geology) 29(Supplement), 32-33, 2014-10
• The 2nd International Symposium on Earth History of Asia 31 October – 3 November, Niigata, Japan
• NAID 120005515503

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