Smaller rainforests helped Carboniferous-Permian reptiles


Phylogeny of reptiles

From the BBC:

30 November 2010 Last updated at 09:12 GMT

Rainforest collapse kickstarted reptile evolution

By Paul Rincon Science reporter, BBC News

The fragmentation of tropical rainforests 300 million years ago helped pave the way for the rise of the dinosaurs, a new study suggests.

In the Carboniferous period, North America and Europe lay at the equator and were covered by steamy rainforest.

Global warming is thought to have brought about the collapse of these tropical habitats, triggering an evolutionary burst among reptiles.

The work, by a British team, is published in the journal Geology.

The forests that covered the ancient supercontinent of Euramerica are colloquially referred to as the Coal Forests.

They are so called because they accumulated a large amount of peat, which later turned into the coal that is mined today.

Towards the end of the Carboniferous, the Earth’s climate is thought to have grown hotter and drier.

“Climate change caused rainforests to fragment into small ‘islands’ of forest,” said co-author Howard Falcon-Lang, from Royal Holloway, University of London.

Dr Falcon-Lang continued: “This isolated populations of reptiles, and each community evolved in separate directions, leading to an increase in diversity.”

To reach their conclusions, the scientists studied the fossil record of reptiles before and after the collapse of the rainforests.

They showed that reptiles became more diverse and even changed their diets as they struggled to adapt to a rapidly changing climate and environment.

Advantage reptiles

Professor Mike Benton, from the University of Bristol, said: “This is a classic ecological response to habitat fragmentation.

“You see the same process happening today whenever a group of animals becomes isolated from its parent population.

“It’s been studied on traffic islands between major road systems or, as Charles Darwin famously observed in the Galapagos, on oceanic islands.”

His Bristol colleague Sarda Sahney commented: “It is fascinating that even in the face of devastating ecosystem-collapse, animals may continue to diversify.”

Amphibians appear to have been hardest hit by the collapse of the rainforests. The relative success of reptiles may have been due to physical adaptations in which they differed from amphibians.

Firstly, the hard-shelled eggs of reptiles could be laid on dry land (most amphibians lay theirs in water). Secondly, reptiles possess protective scales that help them retain moisture (amphibian skin is very permeable to water).

“These key adaptations freed them from the aquatic habitats to which amphibians were tied and gave them ecologic advantage in the widespread drylands that developed,” the researchers write in Geology.

See also here.

Only when tree-like plants with deep roots took hold some 330 million years ago did river banks finally come under control, say researchers: here.

Pompeii-like, a 300-million-year-old tropical forest was preserved in ash when a volcano erupted in what is today northern China. A new study by University of Pennsylvania paleobotanist Hermann Pfefferkorn and colleagues presents a reconstruction of this fossilized forest, lending insight into the ecology and climate of its time: here.

Brazilian formation yields early [Permian] amphibians of tropical Gondwana: here.

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13 thoughts on “Smaller rainforests helped Carboniferous-Permian reptiles

  1. Reptile ‘cousins’ shed new light on end-Permian extinction
    From ANI

    Washington, May 6: A new study has found that the end-Permian extinction may not have been as catastrophic for some creatures as previously thought.

    Led by the University of Bristol, an international team of researchers studied the parareptiles, a diverse group of bizarre-looking terrestrial vertebrates, which varied in shape and size.

    Some were small, slender, agile and lizard-like creatures, while others attained the size of rhinos; many had knobbly ornaments, fringes, and bony spikes on their skulls.

    The researchers found that, surprisingly, parareptiles were not hit much harder by the end-Permian extinction than at any other point in their 90 million-year history.

    Furthermore, the group as a whole declined and diversified time and time again throughout its history, and it was not until about 50 million years after the end-Permian crisis that the parareptiles finally disappeared.

    During the end-Permian extinction, some 250 million years ago, entire groups of animals and plants either vanished altogether or decreased significantly in numbers, and the recovery of the survivors was at times slow and prolonged before new radiations took place.

    By studying the fossil record, palaeontologists can examine how individual groups of organisms responded to the end-Permian event and assess just how dramatic it was.

    However, as the quality and completeness of the fossil record varies considerably, both geographically and stratigraphically, palaeontologists need to find a way to “join the dots” and piece together the fragments of a complex mosaic to give a more satisfactory and better picture of ancient life’s diversity.

    The team led by Dr Marcello Ruta of Bristol’s School of Earth Sciences, including scientists from Germany, Brazil and North America, used the evolutionary relationships among known parareptiles to produce a corrected estimate of changing diversity through time.

    “Evolutionary relationships can be superimposed on a time scale, allowing you to infer missing portions of past diversity. They are powerful tools that complement and refine the known record of extinct diversity,” Ruta said.

    “If you visualize evolutionary relationships in the form of branching diagrams and then plot them on a time scale, new patterns begin to emerge, with gaps in the fossil record suddenly filling rapidly,” Ruta stated.

    Juan Cisneros of the Universidade Federal do Piaui, Ininga, Brazil said: “It is as if ghosts from the past appear all of a sudden and join their relatives in a big family tree – you have a bigger tree.

    “This way, you can start analysing observed and extrapolated abundance of species through time, and you can quantify novel origination and extinction events that would otherwise go unnoticed if you were to look at known finds only,” he said.

    Co-author Johannes Muller of the Museum fur Naturkunde, Berlin added: “Researchers who investigate changing diversity through time have a huge battery of basic and advanced analytical and statistical methods at their disposal to study patterns of diversification and extinction.

    “Classic text-book views of waxing and waning of groups through deep time will certainly benefit, where possible, from the use of evolutionary thinking,” Muller said.

    University of Washington’s Linda Tsuji, also part of the research team, said: “This is the first time that the history of parareptiles has been examined in such detail.

    “But this is only the beginning. These bizarre-looking vertebrates continue to inspire generations of researchers, not only those interested in mass extinctions.

    “They are abundant, diverse, and we still know very little about their biology. We hope that this study will initiate a more in-depth study of the response of terrestrial vertebrates to global catastrophes,” she added.

    The new findings are published online in the journal Palaeontology.

    Copyright Asian News International/DailyIndia.com

    http://www.dailyindia.com/show/438421.php

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  2. http://www.innovations-report.com/html/reports/life_sciences/early_reptiles_moved_179326.html

    How Early Reptiles Moved

    27.07.2011

    University Jena and the Foundation Schloss Friedenstein Gotha Start a Joint Research Project

    Modern scientists would have loved the sight of early reptiles running across the Bromacker near Tambach-Dietharz (Germany) 300 million years ago. Unfortunately this journey through time is impossible.

    But due to Dr. Thomas Martens and his team from the Foundation Schloss Friedenstein Gotha numerous skeletons and footprints of early dinosaurs [NO, NOT DINOSAURS. They came later]have been found and conserved there during the last forty years. “It is the most important find spot of primitive quadruped vertebrates from the Perm in Europe,“ says Professor Dr. Martin S. Fischer from the University Jena (Germany).

    The evolutionary biologist and his team together with the Gotha scientists and other partners are now starting a research project not only to analyze the locomotion of these primeval saurians. They also want to set them back into motion – at least in animation. The Volkswagen Foundation (VolkswagenStiftung) will support the project with about 288.000 Euro during the next two years. “Our first major palaeontologic project“, as zoologist Fischer delightedly calls it.

    The fossils found on the Bromacker date back to the oldest fully terrestrial vertebrates. These so-called amniotes are the first real “land-dwelling animals”. This became possible through a first evolutionary step in which they laid a completely encapsulated egg in whose ‘watery inside’ the offspring could develop. Therefore tadpoles and gills became redundant. “The Bromacker fossils are the closest relatives of the last mutual ancestor of the amniotes that have been found so far,“ Dr. John A. Nyakatura, who oversees the new research project points out, stressing the evolutionary-biological importance of the finds. How did the locomotion system of those amniotes change? They are according to Nyakatura “pivotal to the genealogical tree for evolutionary biologists”. The Jena expert in locomotion research says the crucial questions of the new project are: “Which functionally anatomical consequences does ‚cutting the cord‘ to water have for the locomotion system of the animals?”

    The Jena zoologists and their partners in Gotha, Dresden (both Germany), England and the USA wanted to find out. In their research they cannot only rely on years of expertise but also on one of the fastest X-ray video systems worldwide, which is used at the Friedrich Schiller University. With the help of this system, Dr. Nyakatura and the Paleo-Biomechanist Dr. Vivian Allen who will change from London to Jena in autumn, plan to analyze the locomotion systems of diverse animals resembling the early reptiles. They will observe skinks, tiger salamanders, green iguanas and small crocodiles. In order to do so the animals will move on a treadmill in front of the X-ray video camera that can take up to 2.000 pictures per seconds. Moreover the pressure on the joints will be investigated and footprints will be generated on wet clay. At the end of these analysis a comprehensive locomotion profile of the species is to be created – which in itself will bring science forward.

    The protocol of the footprints will then be compared to the primeval footprints, in order to get an understanding of the early saurians movements. “And this in turn will allow conclusions to be drawn about the find spot and what happened there,” Dr. Martens adds. This is only possible because the Gotha researchers could not only recover numerous footprints but also complete skeletons of unique quality. “The fossils are mind-blowing,“ Nyakatura stresses. The entire animal relics encapsulated in stone slabs are being scanned with the help of the TU Dresden in order to create three-dimensional reconstructions of the skeletons. At the end of the project animated studies of the early saurians will be generated from the scans and the locomotion protocols. ”Thanks to the support of the VolkswagenStiftung and the co-operation with the University Jena we will finally be able to give an insight into the world of the early saurians to the visitors of the ‘Museum of Nature’ in Schloss Friedenstein,” says Dr. Martin Eberle, director of the Foundation Schloss Friedenstein Gotha. Now the researchers are hoping their project will be successful so that they cannot only mount an exhibition on the subject in two years’ time. They will also be able to travel 300 million years back in time due to the innovative animations – and they will watch the early reptiles running.

    Contact:
    Dr. John Nyakatura
    Institute of Systematic Zoology and Evolutionary Biology with Phyletic Museum
    Friedrich Schiller University Jena
    Erbertstraße 1
    D-07743 Jena
    Phone: 0049 (0)3641 / 949183
    Email: john.nyakatura[at]uni-jena.de

    Dr. Martin Eberle
    Stiftung Schloss Friedenstein Gotha
    Schloss Friedenstein
    D-99867 Gotha
    Phone: 0049 (0)3621 / 823411
    Email: sekretariat[at]stiftung-friedenstein.de

    Axel Burchardt | Source: Informationsdienst Wissenschaft
    Further information: http://www.uni-jena.de/en/start_en.html

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