What is "tetronarce"

Tetronarce is a genus of rays, commonly known as electric rays. They are slow-moving bottom-dwellers capable of generating electricity as a defense and feeding mechanism. Tetronarce species tend to attain a much larger size (up to 180 cm TL) than Torpedo species, which are usually small to moderate sized (range from 25 to 80 cm TL) electric rays.