Map of the study area and variation in shell morphotype frequencies.

• Main Authors: Vadim Khaitov (2589874), Julia Marchenko (11177903), Marina Katolikova (2589880), Risto Väinölä (2589886), Sarah E. Kingston (3608393), David B. Carlon (11177906), Michael Gantsevich (2589877), Petr Strelkov (2589883)
• Format: Still Image
• Language: unknown
• Published: 2021
• Subjects: Evolutionary Biology; Ecology; Inorganic Chemistry; Environmental Sciences not elsewhere classified; Biological Sciences not elsewhere classified; morphotype; trossulu; White Sea; semi-diagnostic conchological character; Arctic Barents Sea; species identification; mussels Mytilus edulis L; Baltic Sea; unstudied contact zones; Arctic; Barents Sea
• Online Access: https://doi.org/10.1371/journal.pone.0249587.g001

The bottom panel (maps G-K) shows five geographical contact zones between M . edulis and M . trossulus , maps in the upper panel (A—F)—other studied areas. Pins depict sampling sites. Pie diagrams depict proportions of T-morphotypes (black sector) and E-morphotypes (white sector) in M . trossulus (diagrams with a red border) and M . edulis (those with a blue border) in combined samples from particular regions. If the data on salinity in sampling localities are available and considered in the analyses, it is indicated by the color of pins (light green–brackish, dark green–saline, white–salinity is unknown) and the proportions of the T-morphotypes in combined samples from brackish and saline localities are presented separately in diagrams placed on light and dark green background, respectively. Source data are given in S1 Table and S2 Table . Inkscape 0.92 [ 26 ] was used for producing the map.