A shore crab was tumbling along the aquarium wall the other day and we noticed that he had funny little hairy patches on the inside of his claws. Then we started paying attention, and we discovered that many of the shore crab in our tank have the same fuzzy claw patches. We did some sleuthing, and found this helpful description of the Purple shore crab, aka Hemigrapsus nudus:
Does not live in burrows, as Hemigrapsus oregonensis often does. The chela of males, as of H. oregonensis and P. crassipes, have a prominent tuft of hairlike setae on the palm.
So... as it turns out, male shore crab have hairy palms. We learn something new and exciting every day here at the Hama Hama Store.