The haplotype network based on cytochrome c oxidase subunit I (COI) molecular data showing genetic mutations occurring within species of the genus Amphorina (A). Statistical test of the reliability of the bathymetric distribution patterns (and correlated with depths of brackish and marine environments) of A. viriola sp. nov. (red bar) and A. andra sp. nov. (blue bar) in Swedish waters (B). All specimens of A. viriola sp. nov. occur strictly in a very shallow brackish water layer above the halocline (salinity usually ca. 24–25‰), whereas in the same geographic region A. andra sp. nov. occur only below the halocline (at ca. 15 m depth) in waters with more stable oceanic salinity at 34–35‰.