The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. As of April 2017, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.
Opiliones
Chilean harvestman (Pachyloidellus goliath)
North European harvestman (Leiobunum rotundum) body
A harvestman (a male Phalangium opilio), showing the almost fused arrangement of abdomen and cephalothorax that distinguishes these arachnids from spiders
Arachnids are arthropods in the class Arachnida of the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroons.
"Arachnida" from Ernst Haeckel's Kunstformen der Natur, 1904
Courtship behavior of Thelyphonus sp.
Hubbardia pentapeltis (Schizomida)
Fossil Goniotarbus angulatus (Phalangiotarbida)