Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Amphibians and dinosaurs were the new large predators after the mass extinction

20.03.2014

Immediately after the biggest extinction event of all time there were once again functioning and complete food webs in the oceans of the Early Triassic. Contrary to previous assumptions there were large predators, too. Large predatory fish and amphibians, and later dinosaurs too, were the last link in the food chain. This is demonstrated in new studies by palaeontologists at the Universities of Zurich and Utah, USA.

252 million years ago the largest extinction event occurred at the end of the Permian age. It wiped out almost 90 percent of all life in water.


Fossil von Saurichthys, einem Topräuber unter den Trias-Fischen. Bild: UZH


Fossil und Lebendrekonstruktion von Askeptosaurus, eines grossen Meeresreptils der Trias-Zeit. Solche Thalattosaurier bzw. Meeres- oder Ozanechsen konnten über vier Meter lang werden. Bild: UZH

So far researchers had assumed that the ecosystems gradually recovered from this catastrophe over a long stretch of eight to nine million years and that large predators at the uppermost end of the food chain were the last to reappear.

A Swiss-American team of palaeontologists headed by Torsten Scheyer and Carlo Romano from the University of Zurich demonstrate in their new study that the food nets during the Early Triassic did not recover in stages. Large predators like, for instance, crocodile-like amphibians and later the precursors of the known plesiosaurs and ichthyosaurs went in search of prey in the oceans soon after the end of the mass extinction. 

Large predators in on the action from the very start

Apex predators – large predators at the uppermost end of the food chain – are extremely important for the health and stability of an ecosystem. They eradicate sick and weak animals and exercise constant selection pressure on the species they prey on. Hence, Scheyer and his colleagues wanted to establish whether the apex predators really were missing from the oceans after the mass extinction and how the ecosystems functioned.

The researchers looked at the global distribution of predatory marine vertebrates and their body size in the Early and Middle Triassic and came to surprising conclusions. “The apex marine predators recovered after the large extinction over a very, comparatively short period of time”, says Torsten Scheyer.

The researchers were also able to refute a second theory. Earlier it had been assumed that marine predators grew continuously larger from the Early to the Middle Triassic culminating in the apex predators.

“We now demonstrate that already in the Early Triassic large predators hunted in the seas”, adds Carlo Romano.”The length of the food chains was not shortened by the end-Permian mass extinction. Nor are there any signs of a gradual re-emergence of the classical trophic pyramids from the base to the top”, explains Hugo Bucher.

To gain greater understanding of food webs, attention had to be paid not only to the shape of the food webs but also to the dynamics, i.e. the evolutionary rates of the participating species.

New actors in old roles

The large end-Permian mass extinction led to a completely new composition of apex predators. Large predatory fish were dominant in the Permian age but they had to share this role with predatory crocodile-like amphibians after the mass extinction. Another extinction event around two million years later, the End Smithian crisis, triggered changes in the group of apex predators. From this point in time fish and for the first time reptiles like, for instance, Askeptosaurus were at the uppermost end of the food chains.

“The role of the large predators always remained the same in the ecosystems; only the actors changed over the course of time”, comments Torsten Scheyer when summing up the new results. The researchers are convinced that insight into events in the past will contribute to better understanding of the impact of today’s climate changes on ecosystems.

Literature:
Torsten M. Scheyer, Carlo Romano, Jim Jenks, Hugo Bucher. Early Triassic Marine Biotic Recovery: The Predators’ Perspective. PLOS ONE, March 19, 2014. DOI: 10.1371/journal.pone.0088987


Contact:
Dr. Torsten Scheyer
Palaeontological Institute and Museum
University of Zurich
Tel. + 41 634 23 22
Email:tscheyer@pim.uzh.ch

Dr. Carlo Romano
Palaeontological Institute and Museum
University of Zurich
Karl Schmid-Strasse 4
CH 8006 Zürich
Tel. + 41 634 23 47
Email carlo.romano@pim.uzh.ch

Weitere Informationen:

http://www.mediadesk.uzh.ch

Nathalie Huber | Universität Zürich

Further reports about: Askeptosaurus Recovery Saurichthys Triassic amphibians dinosaurs ecosystems oceans species

More articles from Earth Sciences:

nachricht Researchers find higher than expected carbon emissions from inland waterways
25.05.2016 | Washington State University

nachricht Rutgers scientists help create world's largest coral gene database
24.05.2016 | Rutgers University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Computational high-throughput screening finds hard magnets containing less rare earth elements

Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.

The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...

Im Focus: Atomic precision: technologies for the next-but-one generation of microchips

In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.

In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...

Im Focus: Researchers demonstrate size quantization of Dirac fermions in graphene

Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices

Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.

Im Focus: Graphene: A quantum of current

When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene

In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...

Im Focus: Transparent - Flexible - Printable: Key technologies for tomorrow’s displays

The trend-forward world of display technology relies on innovative materials and novel approaches to steadily advance the visual experience, for example through higher pixel densities, better contrast, larger formats or user-friendler design. Fraunhofer ISC’s newly developed materials for optics and electronics now broaden the application potential of next generation displays. Learn about lower cost-effective wet-chemical printing procedures and the new materials at the Fraunhofer ISC booth # 1021 in North Hall D during the SID International Symposium on Information Display held from 22 to 27 May 2016 at San Francisco’s Moscone Center.

Economical processing

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

International expert meeting “Health Business Connect” in France

19.05.2016 | Event News

 
Latest News

LZH shows the potential of the laser for industrial manufacturing at the LASYS 2016

25.05.2016 | Trade Fair News

Great apes communicate cooperatively

25.05.2016 | Life Sciences

Thermo-Optical Measuring method (TOM) could save several million tons of CO2 in coal-fired plants

25.05.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>