New anaconda species discovered by Las Vegas, NM, couple

Feb. 26—Sarah Corey-Rivas hesitates to pinpoint the exact length and weight of an anaconda held by her and her husband in a photo. She guessed it was about 13 to 15 feet long and between 150 to 200 pounds — a smaller female compared to some of the other specimens she's seen, which have reached around 18 feet.

But she didn't want to overstate.

"That's one of the problems with anacondas," Corey-Rivas said. "People like to exaggerate."

Corey-Rivas and her husband, Jesús Rivas, were lead researchers on a study that found a new species of anaconda. The Las Vegas, New Mexico, couple — both professors at New Mexico Highlands University — believe their research could positively impact conservation efforts for the supersize snake species.

The new snake is named Eunectes akayima, which means "great snake." Although Rivas considered naming the new species after his 2-year-old daughter, he ultimately decided to work with a linguist to compile a list of indigenous words for anaconda from across South America. Akayima is the word used in the area where the northern green anaconda largely dwells.

"I felt that it would be more fair if I named it after the people who could share the land with the anacondas before," Rivas said.

But, dispel visions of explorers trekking through the rainforest, checking under every root and leaf to glimpse an unfamiliar reptile.

Although the couple spent plenty of time tracking down anacondas in South America, this new species was hiding in plain sight. Once thought to be just one species, genetic research revealed the green anaconda is actually two, genetically diverse species. Molecular clock analyses indicate the two species diverged in the Miocene epoch, which occurred between 23 million to 5 million years ago.

Although Rivas has studied anacondas for decades, those differences only became apparent after looking at the snakes at a cellular level.

"Right under my nose, there were two different species," Rivas said. "It's another icon, a species that was so iconic ... and still, two species were snuck under the radar."

Now that researchers know that not one but two types of green anaconda exist; they know that both species' ranges are much smaller than previously thought. That could increase the pressure to protect the animals.

"Ultimately, it's really good news for anacondas," Corey-Rivas said. "That's what matters. It really will help us figure out how to do conservation planning and have specific protection policies in place."

The research has been in the works since 2004, after Rivas and Corey-Rivas met at an international snake ecology conference. Although both shared a background studying snakes, Corey-Rivas had experience studying genetics — and Rivas had his own questions about the genetic background of anacondas.

That initial meeting sparked a yearslong, international research project. Anacondas have a wide range, meaning that studying an entire species required finding slithering specimens from a variety of countries.

Although Corey-Rivas and Rivas were the lead researchers, they collaborated with scientists from around the globe and experts throughout South America, as well as their own students at NMHU. Fifteen authors are listed on the report — 11 of them are Hispanic.

"You look at the list of authors: There's a fellow from Belgium, one from Australia, one from the Netherlands, one from Colombia, one from Brazil, two from the U.S., three from Ecuador, three from Venezuela as well," Rivas said. "It's a truly international collaborative effort."

The study has raised more questions for the researchers. Further research will include studying the effect of heavy metal pollution on anacondas as well as looking at the nuclear genome of yellow anacondas. The study found that three species of anaconda — yellow, dark spotted and Beni — are genetically similar, despite their physical differences. The research paper proposes unifying the three under one species umbrella.

"This pattern of diversity of anacondas, it's humbling to me," Corey-Rivas said. "Also just inspiring for the next steps of continuing to work with them and continuing to try to understand the truth. ... They are just so secretive."