I was already considering Odontodactylus latirostris, but non of the images I found in the www showed such a cyan carapax.
Do you have a link to pictures, showing this color?
Thanks for the compliment - yes, I was snooting, but sort of a 'wide angle' (selfmade) snoot. ;-)
Even though the carapce coloring might not exactly match online pics, here is the desc. from Reef Creature Ident. -
"Size: up to 8cm; Smasher, female antennal scales pink to purplish males red; body mottled greenish brown with reddish highlights; pink and red uropods."
So I think the size, plus the uropods, plus the other description makes it a pretty close match.