interesting crab - what kind is it?

[zoomin]

I am wondering if anyone can help identify a cool crab i spotted yesterday. It is black with red tips on it's large claws. It sat in a high flow area and used what looked like feather dusters attached to it's front legs and pulled food from the water, bring it in to its mouth.

Maybe this is common and I've just never seen it before?

I'll try and get a couple pics this afternoon.