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Giant green anaconda is a new species in the remote Amazon

Anacondas are solitary predators. They spend much of their time alone, submerged in the murky waters of rivers and swamps in South America, where they hunt for prey such as fish, birds, mammals, and even caimans.

Recent research from The University of Queensland has unearthed a surprising truth: anacondas are more diverse than meets the eye.

The green anaconda reigned supreme as the sole king (or queen) of its color class. But hidden within this seemingly unified group lurked a previously unknown species: the northern green anaconda.

Invitation to explore anacondas

“Our team received a rare invitation from the Waorani people to explore the region and collect samples from a population of anacondas, rumoured to be the largest in existence,” explained Professor Bryan Fry. 

“The indigenous hunters took us into the jungle on a 10-day expedition to search for these snakes, which they consider sacred. We paddled canoes down the river system and were lucky enough to find several anacondas lurking in the shallows, lying in wait for prey.”

Genetic differences

The research team then explored the genetic differences between various types of green and yellow anacondas. The goal was to understand how these snakes are related to each other and how diverse they are genetically.

Previously, yellow anacondas were classified into three separate species based on physical appearance and where they live. However, this study suggests these might not be truly distinct groups based on their genes. 

New green anaconda 

While studying the green anaconda’s genes, the scientists found two distinct groups within what was previously thought to be one species. These groups live in different parts of South America, with one group in the north and the other in the south. Interestingly, both types were found in French Guiana, suggesting it might be an area where they meet.

Even though they look almost identical, the genetic differences between the green anaconda groups are much larger than those seen in different types of yellow anacondas. Based on their genes, location, and level of difference, the researchers have classified the northern group as a new species – the northern green anaconda.

Many types of scales

The northern green anaconda is covered in many different types of scales, each with its own location and function. On its underside, from the neck to the tail, it has 247-249 ventral scales. Underneath its tail are 67-68 subcaudal scales, which help identify the specific characteristics of this snake species. Around the middle of its body, it has 65 dorsal scales. These contribute to the overall structure of the snake.

The snake’s back is patterned with 80-90 blotches, which help it camouflage itself in its environment. Additionally, 10-20 of these blotches touch or overlap with each other. On its upper lip, the snake has 14-15 supralabial scales, which might be involved in sensing its surroundings. The lower lip has 16-20 infralabial scales, also likely playing a role in its senses.

Below each eye, there are 2-3 infraocular scales, contributing to the unique shape of its face. Around each eye, there are 8-9 scales, showing the detailed pattern of scales in this area. Finally, near its nostrils, the snake has 4-5 loreal scales and 1-2 supraocular scales, further detailing its facial scale pattern.

Rethinking anaconda taxonomy

The experts also examined the classification of three groups of yellow anacondas: Eunectes notaeus, Eunectes deschauenseei, and Eunectes beniensis. They looked at the snakes’ genes and found that the groups aren’t as distinct as previously thought. 

While E. deschauenseei and E. beniensis have some unique features, their genes are very similar to E. notaeus. This suggests they might not be separate species but rather variations of the same species.

The study proposes that all three groups should be combined into one species, E. notaeus. This challenges the current classification based on location and physical appearance. However, the researchers acknowledge the need for further studies using more genetic data and examining snakes from a wider range of locations.

One possibility is that E. beniensis and E. deschauenseei are simply E. notaeus that live in forests and have adapted to that environment, explaining their darker color and resemblance to another snake species. Until more research is done, the study suggests grouping these snakes together under E. notaeus and carefully considering future classification based on additional evidence.

Broader implications

The findings have crucial implications for conservation strategies. Recognizing the northern green anaconda as a distinct species highlights the need for targeted conservation efforts to protect it. Similarly, the potential reclassification of yellow anacondas requires a reassessment of conservation priorities and strategies for these snakes.

The findings emphasize the importance of habitat protection, not only for the anacondas themselves but also for the broader ecosystem services these top predators provide, such as controlling prey populations.

Their vulnerability to habitat degradation, conflict with humans, and impacts on their prey base necessitates urgent conservation measures to mitigate these threats.

Ultimately, the study serves as a wake-up call. It highlights the importance of ongoing research to understand the true diversity of our planet’s creatures.

Future research

Professor Fry has announced that his next research project will tackle the pressing issue of heavy metal contamination in the Amazon rainforest

“These rare anacondas, and the other species that share this remote ecosystem, face significant challenges. It’s not only these gigantic snakes that are facing environmental threats, but almost all living things in the region,” said Professor Fry.

“The discovery of a new species of anaconda is exciting, but it is critical to highlight the urgent need to further research these threatened species and ecosystems. Of particular urgency is research into how petrochemicals from oil spills are affecting the fertility and reproductive biology of these rare snakes and other keystone species in the Amazon.”

The findings are published in the journal Diversity.


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