Arnold Zwicky's Blog

Elizabeth Daingerfield Zwicky’s flower photos — piles and piles of them, since so many flowers, some with brief blossoming times, are in bloom now — include a number with spiders in them. Well, actually, not spiders, but harvestmen, a similar-looking but quite distinct creature. Here’s one on its own:

Intro to harvestmen, from Wikipedia:

Opiliones (Latin opilio, “shepherd”; formerly Phalangida) are an order of arachnids commonly known as harvestmen. As of December 2011, over 6,500 species of harvestmen have been discovered worldwide

… 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.

… 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 distinguished from even long-legged spiders by their fused body regions and single pair of eyes in the middle of their cephalothorax (spiders have an ‘abdomen’ that is separated from the cephalothorax by a constriction, as well as three to four pairs of eyes, usually around the margins of their cephalothorax).

Particularly in the UK and North America, Opiliones are colloquially known by the name “daddy longlegs” or “granddaddy longlegs” … They are also referred to as “shepherd spiders” in reference to how their unusually long legs reminded observers of the ways that some European shepherds used stilts to better observe their wandering flocks from distance.

… An urban legend claims that the harvestman is the most venomous animal in the world, but possesses fangs too short or a mouth too round and small to bite a human and therefore is not dangerous … This is untrue on several counts. None of the known species of harvestmen have venom glands; their chelicerae are not hollowed fangs but grasping claws that are typically very small and not strong enough to break human skin.

In ordinary language, daddy longlegs are frequently treated as a type of spider and referred to as spiders.

This entry was posted on April 21, 2014 at 7:27 am and is filed under Language and animals, Technical and ordinary language. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.