Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Early mammals used pelvic bones to trot, study finds

17.01.2003


Scientists studying the earliest mammals have been stumped for centuries about the function of two pelvic bones found in the fossil record that most mammals don’t have today. A study published in this week’s issue of the journal Science suggests those bones were involved in locomotion and helped the animals become more mobile, a find that could help researchers pinpoint a key moment in the evolution of mammals.



Biologists at Ohio University and Buffalo State College studied modern-day relations to the earliest mammals — opossums, one of the few types of animals alive today that still has the bones in question, called epipubic bones.

In opossums and a few other marsupials, the epipubic bones are attached to the pelvis and jut into muscles of the stomach. "Kind of like you had two pencils in your belly wall coming from your pelvis up to either side of your navel and they can move up and down," explained Steve Reilly, associate professor of biological sciences at Ohio University and lead author of the study.


Epipubic bones have been found in the earliest mammal fossils and remain in some of the marsupials still living today, and scientists had long thought they supported the animals’ trademark pouch. If that were the case, the bones and attached muscles would move together on one side of the body when the animals walk. But when researchers placed opossums on a treadmill and observed their bones and muscles in motion with a videoflouroscope, they found that the bones move asymmetrically.

"Instead of moving together, one bone is going up and the other is going down," Reilly said. "The epipubic bones act like fishing poles within the belly wall to pull one at a time diagonally across the body, stiffening the body during each trotting step." And, he added, the support from the bones that stiffens the body allowed the animals -- and most likely their ancient ancestors -- to trot.

"These opossums are marsupials that look almost exactly like the fossils we have of mammals that lived millions of years ago," said Reilly, who has studied the evolution of animal locomotion for seven years. "We believe the earliest mammals probably moved just like the opossums because they’re very similar anatomically."

Reilly and his collaborator Thomas White suspect that the development of epipubic bones made the prehistoric creatures more mobile. The increased locomotion made them better predators, helped them to escape predators and allowed them to forage more widely. "Locomotion contributed heavily to the evolution of mammals," Reilly said, "and these bones had something to do with increasing locomotor efficiency in the very earliest mammals."

As the mammals radiated after the dinosaurs went extinct, the epipubic bones in most mammals, including humans, became fused with the pelvis, which allowed mammals to use many gaits besides the trot.

The findings could have implications for paleontologists, Reilly said.

"If the function of the epipubic bone relates to locomotion, that makes the bones more important as a fossil indicator of increased locomotor efficiency," he said. If scientists study the fossil record and figure out when these bones first appeared, he added, it would shed light on a crucial step in the evolution of mammals.

The research is part of a larger study by Reilly and Ohio University colleague Audrone Biknevicius focusing on the evolution of locomotion, which is funded by a three-year, $295,000 National Science Foundation grant.


Written by Kelli Whitlock.

Steve Reilly | EurekAlert!
Further information:
http://www.ohio.edu/researchnews/

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>