Bodiless Sea Spider

Pycnogonid

Pycnogonids seem to have no bodies: often, important organs are in their legs. Pycnogonids are also called sea spiders, but actually are not spiders at all. The name pycnogonid translates to something like "of dense knees", and refers to the fact that their legs are thick and large in comparison to their tiny bodies. They seem almost bodiless. They tend to be small: this fellow is just a few mm across. However, they can grow to close to a yard across in deep or arctic water. I spotted him in shallow water.

Unfortunately, this fellow has lost a couple of legs. Fortunately, pycnogonids can regenerate missing legs: a useful trick, especially since their legs contain vital organs. I wonder how much this fellow's personality will change, after he's regrown his legs.

Together with arachnids (including spiders) and horseshoe crabs (which are not actually crabs), pycnogonids are tentatively grouped into a subphylum within the Arthropods, the Chelicerata.