Leaf insects are an amazing group of tropical animals that imitate ... leaves!

They are not only flat-bodied, but their colors imitate green leaves or the colors of falling/fallen leaves, with complicated patterns. And on their dorsal part they even possess imitations of leaf ribs...

Related to leaf insects, there are the stick insects that perfectly imitate ...twigs!

Generally speaking, insects are difficult to preserve, and most ancient insects were found in amber. But now, researchers have found a fossil of a leaf-imitating insect since 47 million years ago, which bears a striking resemblance to the current species.

This is the first fossil of a leaf insect (Eophyllium messelensis), and also shows that leaf imitation is an ancient and successful evolutionary strategy that has been preserved over the entire Neozoic era (since the disappearance of the dinosaurs).

A research team led by Sonja Wedmann of the Institute of Paleontology in Bonn, Germany, discovered the remains at a well-known fossil site called Messel (hence the species name), in Hessen, Germany. The 2.4-inch (6 cm) long insect was morphologically adapted to the oblong leaves of trees living there at the time, in a subtropical wet climate, like Myrtle trees and Laurel trees. The fossil is also very similar with modern leaf insects in size, shape, and the camouflage designs, like foliage-imitating extensions from its abdomen.

Leaf insects are nocturnal; during the day, to hide from predators, they can stay still for long periods of time, tucking their head into the body to strengthen the leafy appearance.

The fossil species seems to have done the same, as the scientists found its fore legs were curved and formed a notch where the insect's head could be inserted. During the night, when they turn active, leaf insects swing back and forth like a leaf fluttering in the wind.

The cryptic appearance has changed little since the Eocene times, not long after the dinosaur extinction.