Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Turtles use muscle power to breathe due to rigid shell

07.11.2014

Turtle shells are unique in the animal kingdom. In order to be able to breathe in this inflexible casing, tortoises have a muscle sling which is attached to the shell to ventilate the lung.

A team of researchers including paleontologist Torsten Scheyer from the University of Zurich can now reveal that the turtle's ancestor Eunotosaurus africanus already breathed with the aid of such a sling – even though it did not yet have a solid shell. The muscle sling was thus the anatomical prerequisite for the development of the rigid turtle shell.


The present-day extinct ancestors of turtles had a flexible ribcage and breathed, like us, by alternately expanding and contracting the lungs and thorax. The development of a solid shell on the back and belly, however, rendered this kind of respiratory process impossible.

Today’s turtles breathe with the aid of a muscle sling attached to the shell, which contracts and relaxes to aerate the lungs. An international team of researchers from North American, African and European institutes and museums have now discovered the origin of this muscle sling:

in Eunotosaurus africanus, a fossil reptile which lived in South Africa during the Middle Permian around 260 million years ago, as the study just published in Nature Communications reveals.

Instead of a rigid plastron and shell like modern turtles, Eunotosaurus merely had extremely broad, partly overlapping T-shaped ribs. “However, these already heavily restricted the freedom of movement of the ribcage” explains Torsten Scheyer from the Paleontological Institute and Museum of the University of Zurich, who is involved in the study.

Judging by the internal and external bone structures of the ribs, Eunotosaurus evidently only had reduced back muscles, but already possessed a muscle sling that aided respiration. “The small fossil reptile thus provides the explanation as to how the vital adaptation of the breathing apparatus could come about in turtle evolution,” says the UZH paleontologist.

Muscle loop enables shell development

“Eunotosaurus constitutes a morphological link between the body plan of early reptiles and the highly modified body blueprint of the turtles that exist today,” explains Scheyer. The scientists studied the rib plates, so-called costals, of turtle shells and the ribs of various fossil and living vertebrate groups, including mammals, crocodiles and even dinosaurs.

Head of the study Tyler Lyson from the Smithsonian Institution in Washington D.C. and the Denver Museum of Nature and Science, Colorado, adds that, “Based on what we know today, solid shells did not appear in fossil stem turtles until 50 million years after Eunotosaurus.”

The study shows that the steady increase of rigidity of the body wall triggered a separation of the rib and abdominal respiratory muscle functions: The increasing broadening and hardening of the body caused the ribs to become less involved in the respiratory process while the muscles increasingly took over the role. “The ribs became thus free and later completely integrated in the turtle's shell,” says Scheyer.


Literature:
Lyson, T. R., E. R. Schachner, J. Botha-Brink, T. M. Scheyer, M. Lambertz, G. S. Bever, B. Rubidge, and K. de Queiroz. Origin of the unique ventilatory apparatus of turtles. Nature Communications. November 7, 2014. 5:5211. doi: 10.1038/ncomms6211


Contacts:
Dr. Torsten M. Scheyer
University of Zurich
Paleontological Institute and Museum
8006 Zurich
Tel.: +41 44 634 23 22
Email: tscheyer@pim.uzh.ch

Bettina Jakob
Media Relations
University of Zurich
Tel.: +41 44 634 44 39
Email: bettina.jakob@kommunikation.uzh.ch


Weitere Informationen:

http://www.mediadesk.uzh.ch

Bettina Jakob | Universität Zürich

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>