Not a Spider...

Nope, no its not...

Yes, its a type of arachnid, but this is one of The Opiliones.

They are colloquially known as harvestmen, harvesters, or daddy longlegs.

So, for our taxonomically obsessed friends, the phylogenetic position within the Arachnida is disputed; their closest relatives may be the mites (Acari) or the Novogenuata (the Scorpiones, Pseudoscorpiones, and Solifugae).

Why is it not a spider?

Although superficially similar to and often misidentified as spiders (order Araneae), the Opiliones are a distinct order that is not closely related to spiders. They can be easily distinguished from long-legged spiders by their fused body regions and single pair of eyes in the middle of the cephalothorax. Spiders have a distinct abdomen that is separated from the cephalothorax by a constriction, and they have three to four pairs of eyes, usually around the margins of the cephalothorax.

OK??? all clear now....

Why are they called Harvestmen or sometimes "shepherd spiders"? This is 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 a distance.