Featured Research

from universities, journals, and other organizations

Oldest Animal Fossils May Have Been Bacteria

Date:
December 21, 2006
Source:
University of Southern California
Summary:
The oldest-known animal eggs and embryos, whose first pictures made the cover of Nature in 1998, were so small they looked like bugs -- which, it now appears, they may have been. This week, a study in the same prestigious journal presents evidence for reinterpreting the 600 million-year-old fossils from the Precambrian era as giant bacteria.

Lead author Jake Bailey, a graduate student in earth sciences at USC College.
Credit: Photo Lauren Walser

The oldest-known animal eggs and embryos, whose first pictures made the cover of Nature in 1998, were so small they looked like bugs -- which, it now appears, they may have been.

Related Articles


This week, a study in the same prestigious journal presents evidence for reinterpreting the 600 million-year-old fossils from the Precambrian era as giant bacteria.

The discovery "complicates our understanding of microfossils thought to be the oldest animals," said lead author Jake Bailey, a graduate student in earth sciences at the University of Southern California.

Bailey made his discovery by combining two separate findings about Thiomargarita, the world's largest known living bacterium.

In 2005, Thiomargarita discoverer Heide Schulz, from the University of Hannover in Germany, showed that the bacterium promotes deposition of a mineral known as phosphorite.

The fossils identified as eggs and embryos in 1998 came from southern China's Doushantuo Formation, which is rich in phosphorite.

The source for the rare mineral was unknown. Bailey wondered if an ancient relative of Thiomargarita might have been involved.

"The idea is that these bacteria were causing these phosphorite deposits to form," Bailey said.

Also in 2005, University of Georgia marine biologists Samantha Joye and Karen Kalanetra, who are co-authors on Bailey's study, found that Thiomargarita can multiply by reductive cell division, a process rare among bacteria but typical of animal embryos.

Bailey knew that the fossils had been identified as embryos in part because they showed evidence of reductive cell division. Then he thought again about the phosphorite deposits.

"When I put those two pieces together, I said ... perhaps they're not animal embryos at all."

Bailey and his co-authors compared the size and geometrical properties of the Doshuanto fossils and modern Thiomargarita bacteria -- they were nearly identical.

Coupled with the presence of phosphorite, the result pointed strongly to ancient Thiomargarita activity.

"I was shocked that there was this other option out there," Bailey said.

The finding also solved a longstanding puzzle. Proponents of the animal theory had struggled to explain how eggs and embryos could be preserved, as neither fossilizes easily.

These bacteria, on the other hand, make better fossil candidates. And by depositing phosphorite, Thiomargarita even supplies its own rock matrix, or fossil bed.

The Nature study's authors, which include Bailey's adviser Frank Corsetti and USC biology graduate student Beverly Flood, were careful not to rule out the existence of animal fossils from the same geological era. The Doushantuo Formation contains the fossils of many species, some of which have been identified as animals.

While calling the evidence for animal life in the Doushantuo "controversial," Bailey noted that other fossils in the formation "bear little resemblance to Thiomargarita.

"Our paper offers an alternative interpretation of the most abundant microfossils in the Doushantuo Formation," he added. "The structures that we discuss were the first Doushantuo fossils to be interpreted as embryos, and they've been widely accepted as such."

Regardless of the evidence for animal life in the Doushantuo, Bailey's study elevates Thiomargarita to the role of Great Preserver, since without its mineral contribution the other organisms might never have fossilized.

The study appears in the Dec. 20 issue of Nature. Funding for the group's research came from the National Science Foundation, NASA, the U.S. Department of Energy and the National Oceanic and Atmospheric Administration.


Story Source:

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


Cite This Page:

University of Southern California. "Oldest Animal Fossils May Have Been Bacteria." ScienceDaily. ScienceDaily, 21 December 2006. <www.sciencedaily.com/releases/2006/12/061220143854.htm>.
University of Southern California. (2006, December 21). Oldest Animal Fossils May Have Been Bacteria. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2006/12/061220143854.htm
University of Southern California. "Oldest Animal Fossils May Have Been Bacteria." ScienceDaily. www.sciencedaily.com/releases/2006/12/061220143854.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Fossils & Ruins News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Bring Player Pianos Back to Life

Researchers Bring Player Pianos Back to Life

AP (Dec. 17, 2014) Stanford University wants to unlock the secrets of the player piano. Researchers are restoring and studying self-playing pianos and the music rolls that recorded major composers performing their own work. (Dec. 17) Video provided by AP
Powered by NewsLook.com
Domestication Might've Been Bad For Horses

Domestication Might've Been Bad For Horses

Newsy (Dec. 16, 2014) A group of scientists looked at the genetics behind the domestication of the horse and showed how human manipulation changed horses' DNA. Video provided by Newsy
Powered by NewsLook.com
Mozart, Beethoven, Shubert and Bizet Manuscripts to Go on Sale

Mozart, Beethoven, Shubert and Bizet Manuscripts to Go on Sale

AFP (Dec. 16, 2014) A collection of rare manuscripts by composers Mozart, Beethoven, Shubert and Bizet are due to go on sale at auction on December 17. Duration: 00:57 Video provided by AFP
Powered by NewsLook.com
Old Ship Records to Shed Light on Arctic Ice Loss

Old Ship Records to Shed Light on Arctic Ice Loss

Reuters - Innovations Video Online (Dec. 15, 2014) Researchers are looking to the past to gain a clearer picture of what the future holds for ice in the Arctic. A project to analyse and digitize ship logs dating back to the 1850's aims to lengthen the timeline of recorded ice data. Ben Gruber reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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