From MSNBC:
A fossil of a leaf-imitating insect from 47 million years ago bears a striking resemblance to the mimickers of today.
The discovery represents 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 conserved over a relatively long period of time. Scientists led by Sonja Wedmann of the Institute of Paleontology in Bonn, Germany, unearthed the remains at a well-known fossil site called Messel, in Hessen, Germany.
The 2.4-inch-long insect had physical characteristics similar to the oblong leaves of trees living there at the time, including Myrtle trees, legumes, such as alfalfa, and Laurel trees.
More here.