oooo - it just got here, and with some research, I've deduced that it's not a yabbie blue, but a Pracambarus Clarkii female. The confusion arose from the unusual dark blue colour morph and underdeveloped claws(declawed at some point recently I'm assuming.) It took quite a while and a direct, in-hand to picture comparison before I came to a reluctant but firm decision that it's a Clarkii and not Yabbie. The colouring is identical to the Cherax Quadricarnatus, but the head shape and antennae are different, and there is spiny development on the claws congruent with a Clarkii, and not a Cherax. I'm happy in a way, but yet unhappy. I was looking forward to something that would grow to a length pushing a full foot, that would stand a chance in the 150. But instead I got a rarish morph of a common southern swamp crayfish.
The good news is, typically a blue morph clarkii retails for $30ish, but I got her for a respectable $9.99.