Featured Research

from universities, journals, and other organizations

Early Mammals Used Pelvic Bones To Trot, Study Finds

Date:
January 17, 2003
Source:
Ohio University
Summary:
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.

ATHENS, Ohio — 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.


Story Source:

The above story is based on materials provided by Ohio University. Note: Materials may be edited for content and length.


Cite This Page:

Ohio University. "Early Mammals Used Pelvic Bones To Trot, Study Finds." ScienceDaily. ScienceDaily, 17 January 2003. <www.sciencedaily.com/releases/2003/01/030117081103.htm>.
Ohio University. (2003, January 17). Early Mammals Used Pelvic Bones To Trot, Study Finds. ScienceDaily. Retrieved July 27, 2014 from www.sciencedaily.com/releases/2003/01/030117081103.htm
Ohio University. "Early Mammals Used Pelvic Bones To Trot, Study Finds." ScienceDaily. www.sciencedaily.com/releases/2003/01/030117081103.htm (accessed July 27, 2014).

Share This




More Fossils & Ruins News

Sunday, July 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Did ISIS Destroy Jonah's Tomb?

Did ISIS Destroy Jonah's Tomb?

Newsy (July 25, 2014) Unverified footage posted to YouTube purportedly shows ISIS militants destroying a shrine widely believed to be the tomb of the prophet Jonah. Video provided by Newsy
Powered by NewsLook.com
Richard III's Car Park Burial Site Opens to Public

Richard III's Car Park Burial Site Opens to Public

AFP (July 25, 2014) Visitors will be able to look down from a glass walkway on the grave of King Richard III when a new centre opens in the English cathedral city of Leicester, where the infamous hunchback was found under a car park in 2012. Duration: 00:35 Video provided by AFP
Powered by NewsLook.com
Mobile App Gives Tour of Battle of Atlanta Sites

Mobile App Gives Tour of Battle of Atlanta Sites

AP (July 25, 2014) Emory University's Center for Digital Scholarship has launched a self-guided mobile tour app to coincide with the 150th anniversary of the Civil War's Battle of Atlanta. (July 25) Video provided by AP
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins