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 The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>