The smooth butterfly ray (Gymnura micrura) is a species of cartilaginous fish in the family Gymnuridae.

[2] Its natural habitats are shallow seas, subtidal aquatic beds, estuarine waters, and coastal saline lagoons.

[1] Its common name is derived from its compressed body, pectoral fins that are wider than their length, and overall diamond shape.

[4] This group contains over 500 other elasmobranch fishes which includes electric rays, sawfishes, guitarfishes, skates, and stingrays.

[3] These are broad diamond-shaped rays with a short tail that has low dorsal and ventral fin folds.

[7] The smooth butterfly rays have disc widths nearly twice the size of their body lengths and are very flat-bodied (compressed).

They tend to use countershading to blend in with the bottom of their environments in order to hide from predators and to catch prey.

[6] Smooth butterfly rays are found in the western and eastern parts of the Atlantic Ocean (Maryland to Brazil) and the Gulf of Mexico.

[1][11] They use a structure called the lateral line canal; it is located on the dorsal side from the head to the pectoral fins, and are arranged in a branching pattern.