There are only 3 pairs of walking legs plus a pair of claws, so it is not a true crab. I am going to try to get some better photos - the point-and-shoot is clearly not doing the trick. It looks a lot like Allogalathea in color pattern, claw length, etc., but it definitely is missing the white stripe on the claws and the elongated rostrum.
Leslie, I know you are the resident worm expert - do you know any crab folks at your museum or elsewhere? I went to UNCW for my marine bio degree, but all the crab folks there work on temperate species. Thanks!