Spider and Opiliones

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Difference Between Spiders & Opiliones Introduction Although spiders and opiliones are arthropods and belong to the same animal class – Arachnida – opiliones are not spiders. Opiliones, sometimes mistaken for spiders, are known by some as “harvestsmen;” others call them “daddy longlegs.” Spiders in the family Pholcidae are also called “daddy longlegs,” but they are more commonly known as “cellar spiders.” (3) People confuse these two long-legged arachnids, and while they may look similar, numerous differences have been discovered and observed in all aspects of their lives. Body Spiders have two visible body segments – the cephalothorax, which is the rounded head section, and the cylindrical abdomen. (2) The opiliones’ body appears to have a single oval-shaped body segment, but this is because a junction is difficult to discern between the head section and the abdomen. (3) Spiders vary widely in size, but the average cellar spider’s body length is under half an inch and its legs are up to 1.25 inches. By comparison, opiliones, or harvestmen, have a body length of about half an inc...

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