The Carboniferous Period354-290 MY

“Coal Swamps and Glaciers”Jarðsaga 1

- Saga Lífs og Lands –Ólafur Ingólfsson

Early Carboniferous Continents

During the Early Carboniferous the Paleozoic oceansbetween Laurasia and Gondwana began to close.

Early Carboniferous climate

Tropical rainforests cross from Arctic Canada to New-foundland and Western Europe. The desert regions in mid-North America begin to contract. The Southern Hemisphere begins to cool off.

Early Carboniferous climate...• The beginning of the Carboniferous generally had a more uniform, tropical, and humid climate throughoutthe year than exists today. Seasons if any wereindistinct. These observations are based on comparingthe morphology of the plants that exist in the fossil record with plants that are present today. The morphology of the Carboniferous plants resembles the plants that live in tropical and mildly temperate areas today. Many of them lack growth rings, suggesting a uniform climate.

• This uniformity in climate may have been the result of the large expanse of oceans covering huge portions of the continental cratons, as well as higher concentrations of greenhouse gases.

Atmospheric CO2 and T

Important developments in the Carboniferous seas

• The marine environments, following therebound from the late Devonian mass extinction, underwent changes, with crinoidsbecoming more dominant and diverse. The early Carboniferous is sometimes known as the "age of crinoids“ (“Öld Sæliljanna”).• The heavily armored fish from the Devonianbecame extinct. The ray-finned fish became ever more dominant among the fishes...

Life in the Carboniferous seas...

• Shallow, warm, marine waters often floodedthe continents. Attached filter feeders such asbryozoans (mosadýr), were abundant in thisenvironment, and the sea floor was dominated by brachiopods (armfætlur). Trilobites were increasingly scarce while foraminifers(götungar) were abundant.

Golden age of the sharks• The first major shark radiation occurred during theCarboniferous. With the exception of acanthodians(háfiskar), few fishes swam in early Carboniferous seas. The fossil record indicates that 60-75% of fish groups alive during the late Devonian died out before the beginning of the Carboniferous.

• The placoderms (brynháfar) were at the brink of extinction. The misfortune of the placoderms presented a splendid opportunity for sharks in general and one group in particular: the stethacanthids. Perhaps in response to the ecological niches vacated by the placoderms, the stethacanthids exploded into a riot of bizarre forms and lifestyles...

Stethacanthus andhis weird cousins

Male Stethacanthus had a huge flat-topped dorsal fin bristling with enlarged scales. Basically, it looked like a fish with a brush sticking out of its back. Its function is unknown...

Falcatus falcatus – with a strange fin on the back of the male. Used when mating...

The Carboniferous forests

The Carboniferous Period was named so because of itsswamps developed in warm-tropical Equatorial climate. The Carboniferous forests produced tremendous biomass which eventually turned into massive coal deposits.

Large trees developed

Large tree ferns (trjáburknar) developed, which oftenreached heights of 20-35 m. There were also forests of scale trees (lycopods - jafnar) which achieved heights of >45 m.

Examples of lycopods (jafnar), ferns (burknar) and conifers (barrtré)

The lycopodLepidodendron,

reaching heights of 30-45 m

The large tree fern Psaronius, growing to a height of 20 meters

A Cordaite, an earlygymnosperm (berfrævingur)with long, strap-like leaves.

Sigillaria – a huge Carboniferous lycopod (jafni)

Stem base of a Sigillaria, from the upper Westphalian of the Piesberg nearOsnabrück, Germany. Photograph taken in 1886, shortly after its discovery.

Diversity of plant families over the Phanerozoic

Archaeopteris

Cycads: köngulpálmar

Development of plants

A Carboniferouscoal swamp

Formation of coal

Mining Museum of Durham= http://www.dmm.org.uk/educate/cioao1.htm

Major coalfields of the World

Land of opportunity - terrestrialanimals developed large forms...

The millipedes eat de-caying plants and are not predators.

1.5-2 m long millipeds (called arthropleurids) crawledthrough the Carboniferous forests. It is most likely the lack of large terrestrial vertebrate predators that enabled them to grow so large.

The insects were among thefirst animals to colonize land...

The insects: pioneers of most niches...

The story of insect evolution is the story of howorganisms explore new habitats. Where there is thenew habitat, insects are usually the first group of animals to occupy the habitat. Insects were among the first animals to colonize land, and first to fly. Insects comprise about 95% of all known animal species. Actually it is insects instead of humans (nor mammals) who dominate this planet.

Good web site on insects= http://www.geocities.com/pchew_brisbane/index.htm

Insect evolution

The first important step in the evolution of insectswas the development of definite body plan, i.e., thethree body parts - head, thorax and abdomen. This happened approximately 300-350 MY, in Devonian-Carboniferous time.

Insect eyes and wings

During the early Carboniferous, insects developed wingsand the ability to fly. These wings were fixed and couldnot be folded away. One of the conditions for flying isthat there must be a good navigation system, such as a pair of eyes with good eye sight. One of the very earliest identifying features of insects is the compound eye, found only among the insects and some other arthropods.

Web page on insects= http://hannover.park.org/Canada/Museum/insects/beeguide.html

The first Dragonflies

Some of the first dragonflies were enormous. TheProtodonata were a group of gigantic predatory flying

insects, with wingspans of 12 to 75 cm.

A good insect web page= http://www.kendall-bioresearch.co.uk/fossil.htm

The first cockroaches

Eoblattina sp. from Commentry, France

The first cockroaches were also large, measuring up to 10 cm in length...

Why were the early insects so large..?

The number of insect families (ætt) increased from 1 or 2 to more than 100 during the Carboniferous. andmany of the insects were huge, and no one has beenable to say exactly why. One hypotheses is that theflight of the giant dragonfly, along with the wholeCarboniferous insect explosion, may have been made possible by an oxygen-rich atmosphere.

A few years ago, Yale geochemist Robert Berner first suggested that the atmosphere in the Carboniferous was more oxygen rich than at any time before or since--it was 35% oxygen, compared with 21% today.

EarlyCarboniferous

scorpionsThe first terrestrial Scor-pions, believed to haveevolved from the water scorpions, appeared by about 340 million years ago.

The early scorpions produced some very large species andthe largest fossils found so far are ca. 1 m long (i.e. Brontoscorpio willsi). As Scorpions are entirely predatorythey could only move up out of the sea after sufficient prey species had gone before them, these would most likely have been insects, arachnids and millipedes.

“Age of theAmphibians”

Amphibiansevolved rapidly

during the Carboniferous

A Simple Cladogram

Acanthostega gunnariAcanthostega (EastGreenland) is inter-preted as a primarilyaquatic animal, based onthe form of the limb joints and digits, the extensive tail fin and the notochordal vertebrae.

http://www.pbs.org/wgbh/evolution/library/03/4/quicktime/l_034_03.html

The Joggins site, Nova Scotia

The Joggins fossil cliffs are imposing. The alternatingbeds of coal, siltstones or shales and sandstones dip at 20° to the south, so walking north takes you to progres-sively older Carboniferous rocks.

http://earthnet.bio.ns.ca/english/VT/ns/cumberland/2/

Sigillaria tree

Fossils from Joggins

Lepidodendron

Stigmaria

Early AmphibiansDendrerpeton from Joggins, Nova Scotia:

Within the Joggins basin, are the skeletal remains of oneof the earliest known terrestrial vertebrate faunas.

The remains of these early tetrapods havetypically been found in the stumps of uprightfossil tree trunks. The ancient fossil forests of this area, were dominated by the largeCarboniferous lycopod trees Lepidodendron andSigillaria. When these ancient swamps wereperiodically flooded, the bases of the trees were buried. The trees died and the exposed tops fell over, leaving hollowed stumps that became deep pits into which unwary amphibians and reptiles fell and died. The most common tetrapod from this locality is a stem-tetrapod, the temnospondyl Dendrerpeton acadianum.

What did Dendrerpeton look like?Most remains of Dendrerpeton are from the inside of ancient trees and are incomplete and flattened. However, a recently discovered specimen was found, not associated with a tree trunk, that has excellent three-dimensional preservation. This 3-D preservation provides new knowledge about the function of structures in Dendrerpeton.

This animal reached lengths of 1 meter andprobably looked a lot like a large salamander.

Amphibian fossils at JogginsThe most common tetra-podfrom this locality is a stem-tetrapod, the Dendrerpeton acadianum. Over 200 partial skeletons have been found.

Dendrerpeton

Studies of the scull suggest Dendrerpeton had developed a good hearing

Development of millipedasThe fossil record of millipedesdates back to at least theEarly Devonian of Scotland andpossibly as early as the LateSilurian (also in Scotland). The earliest North American record for millipedes comes from the Middle Devonian of eastern Canada.

Millipedes belong to a group of myriapod arthropodscalled the Diplopoda (=double feet); the name comes fromthe presence of two pairs of feet per body segment. They typically inhabit damp terrestrial habitats.

ArthropleuraOther fossils at Joggins include thegigantic millipede Arthropleura, mostly in the form of tracks. Being an invertebrate without hard parts, fossil body parts are rare.

The development of the amnioteegg (líknarbelgsegg): a major

breakthrough

Amniotes appear by the end of the Carboniferous...

• Amniotes are all vertebrates that possess an extraem-bryonic (fósturhimna) layer called an amnion (líknarbelgur). These animals may reproduce on land and may respirate without the assistance of a body of water. Amniotes lay eggs with a water-preserving covering or give live birth.

• The amnion, a layer within the egg or womb, replaces theaquatic environment required for developing vertebrateembryos. The origin of amniotes was a monumental develop-ment in vertebrate evolution. It allowed domination of the land and exploitation of the food resources there.

•Today amniotes exist in a variety of sizes and body forms. Birds, crocodiles, and whales are all amniotes (and you are too).

The amniote egg makes the reptiles...Amphibians, like frogs and salamanders, spend part of their lives under water and part on land. Many of these species must keep their skin moist. All of them mustreturn to water in order to reproduce since their eggs would dry out otherwise. They start life with gills, like fish, and later develop lungs to breathe air.

Reptiles, like turtles, snakes, lizards and alligators have lungs to breathe on land and skin that does not need to be kept wet. They produce the amniote egg, which usuallyhas a leather hard shell that protects the embryo from drying out. This is an advantage over fish and amphibiansbecause the amniote egg can be laid on land where it is usually safer from predators than it would be in lakes, rivers, and oceans.

Did the first reptiles appearalready in Early Carboniferous?

Casiniera, probably no more than 25 cm long — might have lived in a Scottish lagoon 340 MY ago - could be the earliest known fossil of a reptile.

http://www.sciencenews.org/sn_arc99/5_22_99/bob1.htm

Was the development of the Amniote egg a response to Late

Carboniferous climate changes?

Late Carboniferous

The Carboniferous collision of Laurussia (present-day Europe andNorth America) into Godwanaland (present-day Africa and SouthAmerica) helped produce the Appalachian mountain belt of eastern North America and the Hercynian Mountains in the UK. A collisionof Siberia and eastern Europe created the Ural Mountains.

Late Carboniferous climate

Extensive rainforests covered the tropical regions of Pangeawhich was bounded to the north and south by deserts. An ice cap covered the South Pole.

“Wegeners Permo-Carboniferous Ice Age”

Late Carboniferous climate...Global cooling and build-up of glaciers in southernGondwana affected the development of life:

The space available for marine life declined as thesea levels fluctuated and fell when the Gondwanaice sheet locked large amounts of water awayfrom the water cycle. The sea level drop lead tothe mass extinction of shallow marine invertebrates, the gradual decline of swamps, and the increase in terrestrial habitat. This may have spurned the development of the amniote egg and thus led to the development towards mammals...

References, web resources etc• Stanley, Earth System History, chapter 15• Fortey, R. : Life – a natural history of the first 4 billion years of life on

Earth. New York, Vintage Books, 346 pp.• Athyglisverð videomynd:

http://www.pbs.org/wgbh/evolution/library/03/4/quicktime/l_034_03.html• www.clearlight.com/~mhieb/WVFossils/Lycopods.html#anchor236352• www.bbc.co.uk/science/seamonsters/factfiles/stethacanthus.shtml?3dspin• www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/ewald1.htm• http://www.geocities.com/pchew_brisbane/index.htm• http://hannover.park.org/Canada/Museum/insects/beeguide.html• http://www.kendall-bioresearch.co.uk/fossil.htm• http://www.dmm.org.uk/educate/cioao1.htm• http://www.sciencenews.org/sn_arc99/5_22_99/bob1.htm• http://earthnet.bio.ns.ca/english/VT/ns/cumberland/2/• www.elasmo-research.org/education/evolution/golden_age.htm