Unidentified Crayfish

[Dan.J]

Hi Guys

I was fishing today (yes it poured down with rain and I got soaked through)
and I caught a cray fish (fishermans pest - Unless you like eating them) which was nothing unusual, i often catch a lot of the American signal crayfish and throw them back. But.. this one was different, it had a single white marking on each claw and I think it was less red in colour compared to the usual suspects. My immediate thought was that I had been lucky enough to have found a white clawed crayfish but after getting home and looking at pictures on the internet I noticed that they don't actually have this white marking.
I am baffled! - and gutted seeing as I forgot my camera.