News / Science & Technology

Sharks More Evolved than Previously Thought

A Sand Tiger Shark swims in its aquarium, File November 9, 2010.
A Sand Tiger Shark swims in its aquarium, File November 9, 2010.

Related Articles

Mount Everest Climb Exposes Diabetes Mechanism - Study

Using world’s highest mountain as outdoor laboratory, British researchers get clues on what triggers adult onset form of disease

NASA Says Human Landing on Mars on Track for 2030s

US space agency likens steps to get to Red Planet to building blocks that put men on the Moon

Saturn May Be Creating a New Moon

Photo sent by spacecraft shows bright protrusion on edge of one of planet's outer rings, which could be gravitational disturbance caused by small moon
VOA News
Sharks may not be “living fossils,” as was once thought.

Researchers say analysis of a 325-million-year-old shark skeleton could “profoundly affect our understanding of evolutionary history.”
 
Using a fossil of the newly discovered Ozarcus mapesae specimen, scientists at the American Museum of Natural History in New York had a unique chance to study a fossilized skeleton preserved in 3D, according to the researchers.

Since shark skeletons are made of cartilage, fossilized specimens are usually flattened, making it difficult to understand how they were structured.

“Sharks are traditionally thought to be one of the most primitive surviving jawed vertebrates. And most textbooks in schools today say that the internal jaw structures of modern sharks should look very similar to those in primitive shark-like fishes,” said Alan Pradel in a statement

“But we’ve found that’s not the case. The modern shark condition is very specialized, very derived, and not primitive,” said Pradel, a postdoctoral researcher at the museum and the lead author of the study.

According to the researchers, fish heads, including sharks, “are segmented into the jaws and a series of arches that support the jaw and the gills.” The arches were thought to have developed into jaws in early in evolution.

“This beautiful fossil offers one of the first complete looks at all of the gill arches and
associated structures in an early shark. There are other shark fossils like this in existence, but this is the oldest one in which you can see everything,” said John Maisey, a curator in the Museum’s Division of Paleontology and one of the authors on the study.

“There’s enough depth in this fossil to allow us to scan it and digitally dissect out the cartilage skeleton,” he said.
The exceptionally well-preserved fossil of Ozarcus mapesae from two different lateral views. The scale bar is 10 millimeters. (©AMNH/F. Ippolito)The exceptionally well-preserved fossil of Ozarcus mapesae from two different lateral views. The scale bar is 10 millimeters. (©AMNH/F. Ippolito)
x
The exceptionally well-preserved fossil of Ozarcus mapesae from two different lateral views. The scale bar is 10 millimeters. (©AMNH/F. Ippolito)
The exceptionally well-preserved fossil of Ozarcus mapesae from two different lateral views. The scale bar is 10 millimeters. (©AMNH/F. Ippolito)
Using x-rays, scientists were able to view the shape and organization of the arches.

“We discovered that the arrangement of the arches is not like anything you’d see in a modern shark or shark-like fish,” said Pradel. “Instead, the arrangement is fundamentally the same as bony fishes.”

Scientists said that while sharks have been around for 420 million years, it would not be unexpected to see some evolution in their arch and jaw structures, leading to the conclusion that they may not be quite the window to the past as previously thought.

“Bony fishes might have more to tell us about our first jawed ancestors than do living sharks,” Maisey said.

The Ozarcus mapesae fossil was found in Arkansas, which was once home to an ocean basin that housed a diverse set of ancient marine life.

The research is published this week in the journal Nature.

You May Like

HRW: Egypt's Trial of Morsi ‘Badly Flawed’

Human Rights Watch says former Egypt leader's detention without charge for more than three weeks after his removal from office violated Egyptian law; government rejects criticism More

Photogallery Lancet Report Calls for Major Investment in Surgery

In its report published by The Lancet, panel of experts says people are dying from conditions easily treated in the operating room such as hernia, appendicitis, obstructed labor, and serious fractures More

Music Industry Under Sway of Digital Revolution

Millions of people in every corner of the Earth now can enjoy a vast variety and quantity of music in a way that has never before been possible More

This forum has been closed.
Comment Sorting
Comments
     
by: Nathann from: The puget sound region.
April 17, 2014 2:32 PM
Yet again all they have are similarities between species

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Study: Insecticide Damaging Wild Bee Populationsi
X
April 24, 2015 10:13 PM
A popular but controversial type of insecticide is damaging important wild bee populations, according to a new study. VOA’s Steve Baragona has more.
Video

Video Study: Insecticide Damaging Wild Bee Populations

A popular but controversial type of insecticide is damaging important wild bee populations, according to a new study. VOA’s Steve Baragona has more.
Video

Video Data Servers Could Heat Private Homes

As every computer owner knows, when their machines run a complex program they get pretty hot. In fact, cooling the processors can be expensive, especially when you're dealing with huge banks of computer servers. But what if that energy could heat private homes? VOA’s George Putic reports that a Dutch energy firm aims to do just that.
Video

Video Cinema That Crosses Borders Showcased at Tribeca Film Festival

Among the nearly 100 feature length films being shown at this year’s Tribeca Film Festival in New York City are more than 20 documentaries and features with international appeal, from a film about a Congolese businessman in China, to documentaries shot in Pakistan and diaspora communities in the U.S., to a poetic look at disaffected South African youth. VOA’s Carolyn Weaver has more.
Video

Video UN Confronts Threat of Young Radicals

The radicalization and recruitment of young people into Islamist extremist groups has become a growing challenge for governments worldwide. On Thursday, the U.N. Security Council heard from experts on the issue, which has become a potent threat to international peace and security. VOA’s Margaret Besheer reports.
Video

Video Growing Numbers of Turks Discover Armenian Ancestry

In a climate of improved tolerance, growing numbers of people in Turkey are discovering their grandmothers were Armenian. Hundreds of thousands of Armenians escaped the mass deportations and slaughter of the early 1900's by forced conversion to Islam. Or, Armenian children were taken in by Turkish families and assimilated. Now their stories are increasingly being heard. Dorian Jones reports from Istanbul that the revelations are viewed as an important step.
Video

Video Migrants Trek Through Western Balkans to Reach EU

Migrants from Africa and other places are finding different routes into the European Union in search of a better life. The Associated Press followed one clandestine group to document their trek through the western Balkans to Hungary. Zlatica Hoke reports that the migrants started using that route about four years ago. Since then, it has become the second-most popular path into Western Europe, after the option of sailing from North Africa to Italy.
Video

Video TIME Magazine Honors Activists, Pioneers Seen as Influential

TIME Magazine has released its list of celebrities, leaders and activists, whom it deems the world’s “most influential” in 2015. VOA's Ramon Taylor reports from New York.
Video

Video US Businesses See Cuba as New Frontier

The Obama administration's opening toward Cuba is giving U.S. companies hope they'll be able to do business in Cuba despite the continuation of the U.S. economic embargo against the communist nation. Some American companies have been able to export some products to Cuba, but the recent lifting of Cuba's terrorism designation could relax other restrictions. As VOA's Daniela Schrier reports, corporate heavy hitters are lining up to head across the Florida Straits - though experts urge caution.
Video

Video Kenya Launches Police Recruitment Drive After Terror Attacks

Kenya launched a major police recruitment drive this week as part of a large-scale effort to boost security following a recent spate of terror attacks. VOA’s Gabe Joselow reports that allegations of corruption in the process are raising old concerns about the integrity of Kenya’s security forces.
Video

Video Japan, China in Race for Asia High-Speed Rail Projects

A lucrative competition is underway in Asia for billions of dollars in high-speed rail projects. Cambodia, India, Indonesia, Malaysia Thailand and Vietnam are among the countries planning to move onto the fast track. They are negotiating with Japan and the upstart Chinese who are locked in a duel to revolutionize transportation across Asia. VOA Correspondent Steve Herman in Bangkok has details.
Video

Video Scientists: Mosquitoes Attracted By Our Genes

Some people always seem to get bitten by mosquitoes more than others. Now, scientists have proved that is really the case - and they say it’s all because of genes. It’s hoped the research might lead to new preventative treatments for diseases like malaria, as Henry Ridgwell reports from London.
Video

Video Bible Museum Coming to Washington DC

Washington is the center of American political power and also home to some of the nation’s most visited museums. A new one that will showcase the Bible has skeptics questioning the motives of its conservative Christian funders. VOA religion correspondent Jerome Socolovsky reports.
Video

Video Armenia and Politics of Word 'Genocide'

A century ago this April, hundreds of thousands of Armenians of the Turkish Ottoman empire were deported and massacred, and their culture erased from their traditional lands. While broadly accepted by the U.N. and at least 20 countries as “genocide”, the United States and Turkey have resisted using that word to describe the atrocities that stretched from 1915 to 1923. But Armenians have never forgotten.
Video

Video Afghan First Lady Pledges No Roll Back on Women's Rights

Afghan First Lady Rula Ghani, named one of Time's 100 Most Influential, says women should take part in talks with Taliban. VOA's Rokhsar Azamee has more from Kabul.
Video

Video New Brain Mapping Techniques Could Ease Chronic Pain

From Boulder, Colorado, Shelley Schlender reports that new methods for mapping pain in the brain are providing validation for chronic pain and might someday guide better treatment.

VOA Blogs