Masquerade leaves little chemical trace, so its history is normally invisible. The Messel deposit is an exception: fine oil shale that preserved Eocene insects in outline, including a phasmid described in 2007 as Eophyllium messelensis.
The fossil carries the diagnostic features of a leaf insect. The abdomen is broadened and flattened, the femora bear leaf-like lobes, and the overall silhouette matches living Phyllium closely enough that the strategy is unmistakable. It is a male, narrow-bodied like modern males, and the specimen dates to roughly 47 million years ago.
The interesting consequence is ecological. The angiosperm flora of Eocene Europe differed from the tropical Asian forests where leaf insects live today, so the mimicry was not tuned to the particular leaves the modern species sit among. It was already a general resemblance to broadleaf foliage. What the fossil cannot tell is which predators were doing the selecting, since visual hunters at Messel included birds, primates and lizards.