Not even leaves can be trusted anymore, thanks to the ingeniously sneaky antics of a newly discovered spider that looks uncannily like a piece of foliage. Its cover was only blown because it happened to fall into the path of an arachnologist from the Smithsonian Institute named Matjaž Kuntner, whose job it is to look for and examine spiders.

The unusual specimen was found in China’s Yunnan rainforest back in January 2011, and appears to belong to a genus of orb web spider called Poltys. Yet unlike all other species belonging to this genus, the spider displayes expert camouflage, which Kuntner says probably helps it to avoid predators and sneak up on prey.

Several other insects, including grasshoppers and praying mantises, are known to disguise themselves as plants in order to confuse other animals, although this is the first time a leaf masquerade has been seen in an arachnid. Other than this specimen, there are only "a handful of spider genera with phenotypes that resemble flowers, dead twigs, plant detritus, buds, bark, or bird droppings," write the authors.

^{Image: Matjaž Kuntner}

Describing the find in the Journal of Arachnology, Kuntner and his colleagues reveal that the female spider was both green and brown, so that its “abdomen resembled a dead leaf ventrally and a live green leaf dorsally.” Rather than spinning a web, the strange arachnid merely strings dead and live leaves together in a formless bundle, disguising itself as part of a pile of leaves.

In two weeks of searching, the team only came across one other individual of the same species, and later discovered another specimen in a Vietnamese museum. The fact that this spider is so hard to come by indicates that either it is extremely rare, or its disguise is so effective that even professional arachnologists struggle to spot it.