A new species of the world's largest snake species, the green anaconda, was discovered in Ecuador's rainforest by researchers in the Amazon.

The new species, the northern green anaconda (Eunectes akayima), split from its closest snake relatives almost 10 million years ago, but still looks nearly identical in appearance today, even though they are genetically different.

Dutch biologist Freek Vonk shared a video of him swimming alongside the 6.1m, 200kg reptile on Feb. 19.

Northern green anaconda (Eunectes akayima)

The researchers' findings revealed the northern green anaconda (Eunectes akayima) is a separate species, distinct from its counterpart, the southern green anaconda (Eunectes murinus), scientific journal Diversity stated.

It was thought that there was only one species of green anaconda in the wild, the Eunectes murinus.

In his video's caption, Vonk said the snake is a giant, comparing it to his own height of 196cm.

He also said the genetic difference between the northern green anaconda and southern green anaconda is huge, with a difference of 5.5 per cent.

In comparison, humans and chimpanzees only have a genetic difference of around 2 per cent.

The importance of protecting rainforests

Researcher Bryan G. Fry, an Australian, told Reuters that they were using 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.

The Yasuni Biosphere Reserve is located in the north of Ecuador and is one of the areas with the greatest biodiversity per square metre on the planet, according to Unesco.

Fry, who has been investigating anaconda species found in South America for almost 20 years, said the discovery helped show the species split from each other almost 10 million years ago.

He said anacondas are useful sources of information for the ecological health of the area and the potential impacts oil spills in the region have on human health.

Top image via Freek Vonk/ Facebook