Congo River Fish Are Evolving Due To Intense Rapids

Posted: Feb 20 2017, 5:41am CST | by , Updated: Feb 20 2017, 5:49am CST, in News | Latest Science News

 

Congo River Fish are Evolving due to Intense Rapids
A pair of freshwater, rock-dwelling cichlid fish of the genus Teleogramma. Credit: Oliver Lucanus
 

In lower Congo, the genetic diversification is happening over extremely small scales, over distances as small as 1.5 kilometers

One of the most intriguing things about the evolution is that it never stops. Even after 4 billion years, Earth contains millions of different species that evolve necessary traits over time, enabling them to better adapt to their local ecosystems. 

Africa’s Congo River is one of those ecosystems that are rich in aquatic biodiversity. In some cases, fish species living less than a mile away are genetically distinct from each other. However, very little is known about the evolutionary forces shaping this diversity in lower Congo River.

“In this very short section of the Congo, we find a tremendous diversity of fishes," said co-researcher Melanie Stiassny from American Museum of Natural History. "We also know that this part of the river is relatively young, originating only about 3 to 5 million years ago. So what is it about this system that makes it such a pump for species?"

Researchers studied the lower Congo River for the past 10 years before finding out the reason behind its biodiversity. They believe numerous endemic fishes in Congo River are evolving due to the intense hydraulics of the river's rapids and deep canyons. The steep slopes in this section of river are causing changes in water velocity and turbulence and allowing each group of fish to develop separately.

Lower Congo River is remarkably diverse with more than 300 species of fish identified living in this region. But the new study was focused on a single group of strange, rock-dwelling cichlid fishes of the genus Teleogramma. 

When researchers analyzed the genomes of 53 individual fishes each representing a single population of Teleogramma found in the lower region, they found diversity in their genomes. The genetic diversity appears to correspond to geographic regions separated by major hydrological and topographic barriers, indicating these features are likely important drivers of diversification.

“The genetic separation between these fishes show that rapids are working as strong barriers keeping them apart,” said lead study researcher Elizabeth Alter from The City University of New York.

“What’s particularly unique about the lower Congo is that this diversification is happening over extremely small spatial scales, over distances as small as 1.5 kilometers. There is no other river like it.”

This story may contain affiliate links.

Comments

The Author


Hira Bashir covers daily affairs around the world.

 

 

Advertisement

comments powered by Disqus