Pycnogonids feed on soft-bodied invertebrates, in particular cnidarians, sucking at them with their probosces, and larval pycnogonids often live as parasites within cnidarian tissues. The intestine of pycnogonids has extremely long diverticulae (blind pouches) that extend to the ends of the legs.

Pycnogonids have almost no fossil record. Three genera have been found in the Devonian, in the Hunsruck Slate of western Germany. A cast of one of them, Paleopantopus, is shown here. Pycnogonids were once thought to be close relatives of the chelicerates (horseshoe crabs, true spiders, scorpions, etc.). Both pycnogonids and chelicerates have claws on the first appendages and a tubercle with simple eyes, and both lack antennae. However, pycnogonids show so many unusual features, such as the proboscis, reduced abdomen, ovigers, gut diverticulae, and so on, that they may comprise a separate group that probably branched off very early from the arthropod stem.

Please it seems that you are hiding how fast these things are, but just assuming that they are faster than we care to imagine. Isn’t that being a bit presuptuious? You can’t be sure that everyone doesn’t care to imagine how fast these spiders can run underwater.
Please quit teasing us, Mr. Sea Spider Article Guy, we care to imagine. Would you mind posting their speed in MPH (Miles Per Hour) for us American who don’t use the metric system.

This has been going on for the last 3 years. Can anyone help me? Can anyone put me in touch with someone who could maybe take skin samples to find out what time of spider is was that bit him (if in fact it was a spider). I don’t know if there is any treatment but I would like to at least know if it was a spider. He won’t go to the Dr with this complaint as he fears he will be laughed at & I am in agreement with him. I would rather he went straight to a specialist in spider bites. We’d both be really grateful for some help.