This article does not describe a species with three sexes. It describes a species with two sexes that can co-exist (or not) in the same individual organism. It

This article does not describe a species with three sexes. It describes a species with two sexes that can co-exist (or not) in the same individual organism. It's somewhat unique because of the "(or not)" — most anisogamous species have either two phenotypes that produce one and only one of the gametes, or a single phenotype that produces both (like many flowering plants). Still only two sexes, though—just more than two phenotypes.