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Pretty similar are:
Mexichromis cf. mariei which differs by its few very small tubercles, which are tipped in white,
Mexichromis multituberculata which can have also a series of orange patches at the edge of the mantle, usually these patches are blueish-purple. It differs by having numerous purple-tipped large tubercules.
More information on Mexichromis mariei are on Bill Rudman's Sea-Slug Forum!