In my land Corrientes we call them Teyu, the two colors are called teyu Taragui loas two images below are teyu are varieties that according to the edition can reach more than one meter, the images of the medium are the most common.
This is a very well-behaved animal, there is even a legend that is called Teyu Yagua.
Some time ago wrote a post with this topic.
I hope you like it.