  opiliones  (latin opilio, "shepherd"; formerly phalangida) is an order of arachnids commonly known as harvestmen. , over 6,500 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. the order opiliones includes four suborders: cyphophthalmi, eupnoi, dyspnoi, and laniatores, and representatives of each can be found on every continent except antarctica (with the exception of dyspnoi, which is restricted to north america and eurasia). well-preserved fossils have been found in the 400-million-year-old rhynie cherts of scotland, which look surprisingly modern, indicating that their basic body plan appeared very early on, and, at least in some taxa, has changed little since that time. their phylogenetic position within arachnida is disputed: their closest relatives may be the mites (acari) or the novogenuata (the scorpiones, pseudoscorpiones and solifugae). although superficially similar to and often confused with spiders (order araneae), opiliones is a distinct order that is not closely related to spiders within arachnida. they can be easily d
Arachnids Harvestmen