Since I recieved questions about how I could know that this particular specimen was a female, I took a photo of the characteristic that is a dead give-away among true crabs and crab-like relatives - the shape of the abdomen. As we see here, it's wide and rounded, perfect for carrying a large brood of eggs. Thus, we have a female. Males have a much more sharp and pointy abdomen, more suited for the act of internal fertilization.

Of course, to be absolutely sure you'd have to bend the abdomen open and take a closer look at the inside, and action that doesn't harm the crab but pisses them off royally. However, to get a photo of that, I'd need an assistant, since juggling and opening a crab up would require both hands,leaving none free for photography :>

This spawned a line of thought in the Dreamkeepers chatroom that might end with dire consequences indeed... Anatomically correct crustacean porn was mentioned.