The mapar? (H. marginatus) found at the mouth of the Par? River up to near the Tucuru? dam is popularly known as "Mapar?-do-nosso", they live in lentic environments, are smaller, robust and the color of their backs is a lighter gray, while the mapar? found both along the course of the Tocantins River above the dam, and in the dam lake (lotic environments), are elongated and narrow with a dark back, they are popularly known as "Paulo Isid?rio". It is one of the most traded fish in the Lower Tocantins.