Limacina helicina appears like any other sea snail, until it beat what seemed like delicate wings and 'flies' in the water. A study published recently in the Journal of Experimental Biology said that the small species of sea snail moves across water with the help of the same kind of motion used by an insect in flying.

The researchers called it a remarkable example of convergent evolution. They said that the ancestors of zooplankton and the ones of flying insects diverged around 550 million years back.

The study found that the sea snail's movements were more like a fruit fly's as compared to other zooplankton.

L. helicina, which stays in cold Pacific waters, possesses two smooth swimming appendages that 'flap in a complex three-dimensional stroke pattern that resembles the wingbeat kinematics of flying insects'.

The researchers said that other kinds of zooplankton generally, paddle in the water using drag-based propulsion instead of flying.

While speaking to the Journal of Experimental Biology, study co-author David Murphy said that both the sea snail and fruit fly, "clap their wings together at the top of a wing beat before peeling them apart, sucking fluid into the V- shaped gap between the wings to create low-pressure vortices at the wing tips that generate lift".

As per the scientists flying instead of paddling gives an advantage to L. helicina. According to the study, the likely benefit is that flapping appendages are mechanically more efficient in comparison to rowing appendages at all swimming speeds.

Scientists were able to observe the snail's movement closely with the help of a latest 3D system built by Murphy that can visualize fluid movements around minute animals. The small creatures were collected in Oregon and were moved to Atlanta for study. Murphy said that he was surprised to see that sea butterflies turned out to be honorary insects.