News / Science & Technology

Scientist: Ancient Fish Shows Signs of Rear-Leg Development

Reuters
Fossils of an ancient fish species discovered in the Canadian Arctic show that hind legs evolved from fins some 375 million years ago, challenging a theory that they developed only after vertebrates took to land, according to research published this week.
 
The remains of the fish, the Tiktaalik roseae, were discovered in 2004 on southern Ellesmere Island in northern Canada by a team of scientists that included a now-deceased Harvard University professor, Farish Jenkins, according to the findings published in the Proceedings of the National Academy of Sciences, a scientific journal.
 
Researchers had initially focused only on specimens containing the front portion of the fish but subsequently discovered pelvises and partial pelvic fin material from the rear portion that were comparable to those of some early four-legged animals, with a ball-and-socket hip joint.
 
“This is an amazing pelvis, particularly the hip socket, which is very different from anything that we knew of in the lineage leading up to limbed vertebrates,” Ted Daeschler, associate curator of vertebrate zoology at Drexel University in Philadelphia and a co-author of the study, said in a statement.
 
The prevailing scientific understanding, Daeschler said, was based on “a 'front-wheel drive' idea that these animals were primarily using their front limbs for locomotion,” while hind limbs were small and not necessarily used for movement.
 
“It looks like this shift actually began to happen in fish, not in limbed animals,” Neil Shubin, a University of Chicago professor and co-author of the study, said in the statement. “It's reasonable to suppose with those big fin rays that Tiktaalik used its hind fins to swim like a paddle. But it's possible it could walk with them as well.”
 
The Tiktaalik roseae looked like a cross between a fish and a crocodile, with lobe fins, a broad flat head and sharp teeth, according to Drexel. It hunted in shallow freshwater environments and grew to a length of up to nine feet (2.7 meters).
 
It had gills, scales and fins, but also features associated with four-legged animals — a mobile neck, a robust ribcage and primitive lungs — the university said. Its large forefins had shoulders, elbows and partial wrists, allowing it to support itself on ground.
 
Such features make the fish one of the best-known transitional species between fish and land-dwelling tetrapods, or animals with two pairs of limbs, the university said.

You May Like

Unpaid Kurdish Fighters Sign of Economic Woes

Sharp cuts in Kurdistan's budget by Baghdad, falling oil revenue, coping with refugees, inflated public sector have hit regional economy hard More

Koreas Exchange List of Envoys for Family Reunion Talks

Officials will discuss date, venue and number of participants for reunion; Seoul hopes to hold event late this month More

China Targets 197 in Online Speech Crackdown

Nearly 200 punished for 'spreading rumors' online in ongoing crackdown on free speech More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Calais School Offers Another Face of Europe’s Migrant Crisisi
X
Lisa Bryant
September 02, 2015 6:19 PM
Europe is facing mounting criticism over how it’s handling its biggest migration crisis since World War II. But not all Europeans believe building walls or passing repressive policies are the answer. A school for migrants in the French port city of Calais, is opening doors and building bonds across nationalities. VOA's Lisa Bryant reports.
Video

Video Calais School Offers Another Face of Europe’s Migrant Crisis

Europe is facing mounting criticism over how it’s handling its biggest migration crisis since World War II. But not all Europeans believe building walls or passing repressive policies are the answer. A school for migrants in the French port city of Calais, is opening doors and building bonds across nationalities. VOA's Lisa Bryant reports.
Video

Video Russia-Japan Relations Cool as Putin Visits China for WWII Anniversary

Russian President Vladimir Putin is in Beijing for commemorations of the 70th anniversary of China's WWII victory over Japan. Putin is expected to visit Japan later this year, but tensions between Tokyo and Moscow over islands disputed since the war, and sanctions over Ukraine, could pour cold water on the plan. VOA's Daniel Schearf reports.
Video

Video Kurdish Fighters on IS Frontline Ready for Offensive

Finger on the trigger, the Kurdish Peshmerga soldier stared across the dust at a village taken over by Islamic State extremists. The Kurdistan’s Khazir frontline, just 45 minutes from the Islamic State stronghold of Mosul. And at this point, the militants were less than two kilometers away. VOA's Sharon Behn reports.
Video

Video Yemen ‘on Brink of Disaster’ as Medical Shortages Soar

Aid agencies warn Yemen is on the brink of humanitarian disaster – with up to half a million children facing severe malnutrition, and hospitals running out of basic medicines. There are fears Yemen's civil war could escalate as the coalition led by Saudi Arabia tries to drive back Houthi rebels, who seized control of much of the country earlier this year. Henry Ridgwell reports.
Video

Video Apps Helping Kenyan Businesses Stay Ahead of Counterfeiters

Counterfeit goods in Kenya cost the government as much as $1 billion each year in lost tax revenues. The fake goods also hurt entrepreneurs who find it hard to carve out a niche in the market and retain customers. But as Lenny Ruvaga reports from Nairobi, information technology is being used to try to beat the problem.
Video

Video Nobel Prize Winner Malala Talks to VOA

Nobel Peace Prize winner Malala Yousafzai met with VOA's Deewa service in Washington Sunday to talk about women’s rights and unveil a trailer for her new documentary. VOA's Katherine Gypson has more.
Video

Video War, Drought Threaten Iraq's Marshlands

Iraq's southern wetlands are in crisis. These areas are the spawning ground for Gulf fisheries, a resting place for migrating wildfowl, and source of livelihood for fishermen and herders. Faith Lapidus has more.
Video

Video Colombians Flee Venezuela as Border Crisis Escalates

Hundreds of Colombians have fled Venezuela since last week, amid an escalating border crisis between the two countries. Last week, Venezuelan President Nicolas Maduro ordered the closure of a key border crossing after smugglers injured three Venezuelan soldiers and a civilian. The president also ordered the deportation of Colombians who are in Venezuela illegally. Zlatica Hoke reports.
Video

Video Rebuilding New Orleans' Music Scene

Ten years after Hurricane Katrina inundated New Orleans, threatening to wash away its vibrant musical heritage along with its neighborhoods, the beat goes on. As Bronwyn Benito and Faith Lapidus report, a Musicians' Village is preserving the city's unique sound.
Video

Video In Russia, Auto Industry in Tailspin

Industry insiders say country relies too heavily on imports as inflation cuts too many consumers out of the market. Daniel Schearf has more from Moscow.
Video

Video Scientist Calls Use of Fetal Tissue in Medical Research Essential

An anti-abortion group responsible for secret recordings of workers at a women's health care organization claims the workers shown are offering baby parts for sale, a charge the organization strongly denies. While the selling of fetal tissue is against the law in the United States, abortion and the use of donated fetal tissue for medical research are both legal. VOA’s Julie Taboh reports.
Video

Video Next to Iran, Climate at Forefront of Obama Agenda

President Barack Obama this week announced new initiatives aimed at making it easier for Americans to access renewable energy sources such as solar and wind. Obama is not slowing down when it comes to pushing through climate change measures, an issue he says is the greatest threat to the country’s national security. VOA correspondent Aru Pande has more from the White House.
Video

Video Arctic Draws International Competition for Oil

A new geopolitical “Great Game” is underway in earth’s northernmost region, the Arctic, where Russia has claimed a large area for resource development and President Barack Obama recently approved Shell Oil Company’s test-drilling project in an area under U.S. control. Greg Flakus reports.
Video

Video Philippine Maritime Police: Chinese Fishermen a Threat to Country’s Security

China and the Philippines both claim maritime rights in the South China Sea.  That includes the right to fish in those waters. Jason Strother reports on how the Philippines is catching Chinese nationals it says are illegal poachers. He has the story from Palawan province.
Video

Video China's Spratly Island Building Said to Light Up the Night 'Like A City'

Southeast Asian countries claim China has illegally seized territory in the Spratly islands. It is especially a concern for a Philippine mayor who says Beijing is occupying parts of his municipality. Jason Strother reports from the capital of Palawan province, Puerto Princesa.

VOA Blogs