Complex sentence: The Urolophidae are a family of rays in the order Myliobatiformes, commonly known as stingarees or round stingrays; this family formerly included the genera "Urobatis" and "Urotrygon" of the Americas, which are presently recognized as forming their own family Urotrygonidae.
Split into simpler sentences: The Urolophidae are a family of rays in the order Myliobatiformes, commonly known as stingarees or round stingrays. This family formerly included the genera "Urobatis" and "Urotrygon" of the Americas, which are presently recognized as forming their own family Urotrygonidae.