Reuters

Researchers in the Amazon have discovered the world`s largest snake species - an enormous green anaconda - in Ecuador`s rainforest that split off from its closest relatives 10 million years ago though they still nearly look identical to this day.

A video shared online shows the scale of these 20-foot-long (6.1-meter-long) reptiles as one of the researchers, Dutch biologist Freek Vonk, swims alongside a giant 200-kilo (441-pound) specimen.

It was thought that there was only one species of green anaconda in the wild, the Eunectes murinus, but the scientific journal Diversity this month revealed that the new "northern green anaconda" belongs to a different, new species, Eunectes akiyama.

"What we were there to do was use the anacondas as an indicator species for what kind of damage is being done by the oil spills that are plaguing the Yasuni in Ecuador, because the oil extraction is absolutely out of control," researcher Bryan G Fry said.

Fry - an Australian professor of biology at the University of Queensland who for almost 20 years has been investigating anaconda species found in South America - told Reuters the discovery allows them to show that the two species split from each other almost 10 million years ago.

"But the really amazing part was, despite this genetic difference, and despite their long period of divergence, the two animals are completely identical," he said.