crab eaten by carpet?

[rt67ghy]

I had an unidentified crab in my tank for about 8 months. Yesterday I found its claws on either side of my haddoni carpet. I'm wondering if the carpet ate it or the claws were from a molt. Any input would be appreciated. The pic was taken with a macro lens and the claws are at the bottom of a tea cup.

http://imgur.com/mqzoS7E

 

[rt67ghy]

Here's an update. The crab lives. Happy to see the little critter.