The Howler Monkey Snake: A Weird Species from Northwestern Brazil

The Howler Monkey Snake of Northwestern Brazil (near the boarder of Colombia) is described as having a head similar looking toward a howler monkey's with horrifying teeth that have sleek, elongated bodies (growing up to 18 feet long in length) with markings similar toward a boa constrictor. They're known to have also four webbed claws which allows it to steer while swimming at speeds up to 5 mph. Being mainly shy, the Howler Monkey Snake creates a den underneath the water level nearby mainly lakes to avoid humans and predators. While looking for one of these elongated species of primate, one must listen for a noisy din that sounds like a group of howler monkeys coming from a nearby a water source because the sounds that this creature makes can be heard from their dens from underneath the water. They're mostly active during rainy nights. The Howler Monkey Snakes are also known to wallow in mud to help keep their waterproof fur free from parasites, can be found in trees by slowly circling the tree trunk like a spiral staircase, and are most likely to be found during the day hiding in swamp vegetation. Howler Monkey Snakes uses both venom from their saliva and constriction to kill their prey and then, like a python or anaconda, they swallow their prey whole (including an unlucky human being if possible).
The Howler Monkey Snakes is a hard creature to group with known animals because of it's strange features. For example, the head and fur must indicate that this species must be a type of primate or mammal but, at the same time it could be a weird snake/reptile thanks to the venom (either like a venomous snake or a komodo dragon) and hunting strategies it uses to hunt prey.