Supplementary File The sources of the data given in Table 1

Supplementary File
The sources of the data given in Table 1.
The data on host range and distribution of the microphallids of the “pygmaeus” group (MGP) were obtained during long-term field surveys (K. Galaktionov, personal observations, partly published) or taken from the literature available (see the list of references below).
MPG records in the first intermediate (molluscan) hosts
Blakeslee, A. M. H. and Byers, L. (2008). Using parasites to inform ecological history: comparisons among three congeneric marine snails. Ecology 89, 1068-1078.

Ching, H. L. (1961). Three trematodes from Harlequin Duck. Canadian Journal of Zoology 39, 373-376.

Ching, H. L. (1991). List of larval worms from marine invertebrates of the Pacific coast of North America. Journal of the Helminthological Society of Washington 58, 57-68.

Chubrick, G. K. (1966). Fauna and ecology of trematode larvae from molluscs of the Barentz Sea and White Sea. In Life-cycles of Parasitic Worms from Northern Seas (ed. Poljansky Yu. I.), pp. 78-159. Nauka, Leningrad (in Russian).

Combescot-Lang, C. (1976). Etudes des trematodses parasites de Littorina saxatilis (Olivi) et de leurs effet sur cet hôte. Annales de Parasitologie Humaine et Comparee 51, 27-36.

Galaktionov, K. V. (1983). Microphallids of the “pygmaeus” group. I. Description of species Microphallus pygmaeus (Levinsen, 1881) nec Odhner, 1905 and M. piriformes (Odhner, 1905) nom. nov. (Trematoda: Microphallidae). Vestnik Leningradskogo Universiteta (Bulletin of the Leningrad University) 15, 20-30 (in Russian).

Galaktionov, K. V. (1984). Microphallids of the "pygmaeus" group. II. Microphallus triangulatus sp. nov. (Trematoda: Microphallidae). Vestnik Leningradskogo Universiteta (Bulletin of the Leningrad University) 3, 5-11 (in Russian).

Galaktionov, K. V. (1993). Life Cycles of Trematodes as Components of Ecosystems. Kola Scientific Centre of the Russian Academy of Sciences Press, Apatity (in Russian).

Galaktionov, K. V. (1996). Life cycles and distribution of seabird helminths in the Arctic and sub-Arctic regions. Bulletin of the Scandinavian Society for Parasitology 6 (2), 31-49.

Galaktionov, K. V. (2009). Description of the maritae and determination of the species status of Microphallus pseudopygmaeus sp. nov. (Trematoda: Microphallidae). Parazitologiya 43: 289-299 (in Russian).

Galaktionov, K. V. and Bustnes, J. O. (1995). Prevalence of trematodes in intermediate hosts compared to the distribution of final hosts: a study of periwinkles and marine birds. Sarsia 80, 489-496.

Galaktionov, K. V. and Bustnes, J. O. (1999). Distribution patterns of marine bird digenean larvae in periwinkles along the southern Barents Sea coast. Diseases of Aquatic Organisms 37, 221-230.

Galaktionov, K. V. and Marasaev, S. F. (1986). Ecological analysis of trematode fauna of gastropods in the south-eastern part of the Barents Sea. Parazitologiya 20, 455-460 (in Russian).

Galaktionov, K. V. and Skirnisson, K. (2000). Digeneans from intertidal molluscs of SW Iceland. Systematic Parasitology 47, 87-101.

Galaktionov, K. V., Marasaev, S. F. and Marasaeva, E. F. (1993). Parasites in maritime ecosystems. In Environment and Ecosystems of the Franz Josef Land (Archipelago and Shelf) (ed. Matishov, G. G.), pp. 213-221. Kola Scientific Centre Press, Apatity.

Galaktionov, K. V., Regel, K. V. and Atrashkevich, G. I. (2010). Microphallus kurilensis sp. nov., a new species of microphallids from the “pygmaeus” species group (Trematoda, Microphallidae) from the coastal areas of Okhotsk and Bering Seas. Parazitologiya 44, 496-507 (in Russian).

Galaktionov, K. V., Bulat, S. A., Alekhina, I. A., Saville, D. H., Fitzpatrick, S. M. and Irwin, S. W. B. (2004). An investigation of evolutionary relationships within “pygmaeus” group microphallids (Trematoda: Microphallidae) using genetic analysis and scanning electron microscopy. Journal of Helminthology 78, 231-236.

Granovitch, A. I. and Johannesson, K. (2000). Digenetic trematodes in four species of Littorina from the West coast of Sweden. Ophelia 53, 55-65.

James, B. L. (1968). Studies on the life-cycle of Microphallus pygmaeus (Levinsen, 1881) (Trematoda: Microphallidae). Journal of Natural History 2, 155-172.

James, B. L. (1968). The distribution and keys of species in the family Littorinidae and of their digenean parasites in the region of Dale, Pembrokenshire. Field Studies 2, 615-650.

Lauckner, G. (1980). Diseases of Mollusca: Gastropoda. In Diseases of marine animals. Vol I. (ed. Kinne O.), pp. 311-424. John Wiley & Sons, Chichester, New York, Brisbane, Toronto.

Pohley, W. (1976). Relationships among three species of Littorina and their larval Digenea. Marine Biology 37, 179-186.

Saville, D. H., Galaktionov, K. V., Irwin, S. W. B. and Malkova, I. I. (1997). Morphological comparison and identification of metacercariae in the “pygmaeus” group of microphallids, parasites of seabirds in western palearctic regions. Journal of Helminthology 71, 167-174.

Skirnisson. K. and Galaktionov, K. V. (2002). Life cycles and transmission patterns of seabird digeneans in SW Iceland. Sarsia 87, 144-151.

Stunkard, H. W. (1983). The marine cercariae of the Woods Hole, Massachusetts region, a review and a revision. The Biological Bulletin of the Marine Laboratory, Woods Hole 164, 143-162.

Threlfall, W. and Goudie, R. I. (1977). Larval trematodes in the rough periwinkle, Littorina saxatilis (Olivi), from Newfoundland. Proceedings of the Helminthological Society of Washington 44, 229-232.

Tsimbaljuk, A. K., Kulikov, V. V. and Baranova, T. I. (1968). On the biology of Microphallus calidris Belopolskaia et Ryjikov, 1963 (Trematoda: Microphallidae). In Helminths of animals of the Pacific Ocean (ed. Skrjabin, K. I. and Mamaev, Yu. L.), pp. 125-128. Nauka, Moscow (in Russian).

Tsimbaljuk, A.K., Kulikov, V.V., Ardasheva, N.V. and Tsimbaljuk, E.M. (1978). Helminths of invertebrates from the intertidal zone of the Iturup island. In Fauna and vegetation of the shelf of the Kuril islands (ed. Kusakin, O.G.), pp. 69-126. Nauka, Moscow (in Russian).

Werding. B. (1969). Morphologie, Entwicklung und Ökologie digener Trematoden-Larven der Strandschnecke Littorina littorea. Marine Biology 3, 306-333.

Williams, I. and Ellis, C. (1976). Larval Digenea in Shetland. Glasgow Naturalist 19: 307–315.

Zaslavskaya, N. I. (2006). Allozyme comparison of Littorina species from the northwestern Pacific. Journal of Molluscan Studies 72, 163-166.
MPG records in the final hosts
Atrashkevich, G. I., Orlovskaja, O. M. and Regel, K. V. (2008). The first record of parasites of the Sea of Okhotsk population of common eider (Somateria mollissima). In Proceedings of the IV congress of the Russian society of parasitologists “Parasitology in XXI century – problems, methods, solutions” Vol. I (ed. Galaktionov, K.V. and Dobrovolskij, A.A.), pp. 36-39. Lema Press, St. Petersburg (in Russian).

Baer, J. G. (1956). Parasitic helminths collected in West Greenland. Meddelelser om Grønland 124, 1-55.

Bakke, T. A. (1972). Check list of helminth parasites of the common gull (Larus canus L.). Rhizocrinus 1: 1-20

Belogurov, O. I. , Leonov, V. A. and Zuev, L. S. (1968). The fauna of helminths of the fish-eating birds (gulls and alcids) from the Sea of Okhotsk coast. In Helminths of animals of the Pacific Ocean (ed. Skrjabin, K. I. and Mamaev, Y. L.), pp. 105-124. Nauka, Moscow (in Russian).

Belopolskaya, M. M. (1952). Parasite fauna of marine waterfowl. Scientific Proceedings of the Leningrad University 141, ser. Biol., 28, 127-180 (in Russian)

Belopolskaya, M. M. (1952). Family Microphallidae Travassos, 1920. In Trematodes of Animals and Man. Vol. 4. (ed. Skrjabin, K. I.), pp. 618-756. USSR Academy of Sciences Press, Moscow-Leningrad (in Russian).

Belopolskaya, M. M. (1959). Parasite fauna of waders of the Sea of Japan and the Barents Sea coasts. In Ecological Parasitology (ed. Poljansky, Yu. I.), pp. 22-57. Leningrad University Press, Leningrad (in Russian).

Belopolskaya, M. M. (1963). Family Microphallidae Travassos, 1920. In Trematodes of Animals and Man. Vol. 21. (ed. Skrjabin, K. I.), pp. 259-502. USSR Academy of Sciences Press, Moscow-Leningrad (in Russian).

Brinkman, A. (1975). Trematodes from Greenland. Meddelelser om Grønland 205, 1-88.

Bychowskaya-Pawlovskaya, I. E. (1962). Trematodes of Birds of the USSR. USSR Academy of Sciences Press, Moscow, Leningrad (in Russian).

Deblock, S. (1971). Contribution à l’étude des Microphallidae Travassos, 1920. XXIV. Tentative de phylogénie et de taxonomie. Bulletin de Muséum National d’Histoire Naturelle 3e sér, 7, Zoologie 7, 353-469.

Galaktionov, K. V. (1983). Microphallids of the “pygmaeus” group. I. Description of species Microphallus pygmaeus (Levinsen, 1881) nec Odhner, 1905 and M. piriformes (Odhner, 1905) nom. nov. (Trematoda: Microphallidae). Vestnik Leningradskogo Universiteta (Bulletin of the Leningrad University) 15, 20-30 (in Russian).

Galaktionov, K. V. (1984). Microphallids of the "pygmaeus" group. II. Microphallus triangulatus sp. nov. (Trematoda: Microphallidae). Vestnik Leningradskogo Universiteta (Bulletin of the Leningrad University) 3, 5-11 (in Russian).

Galaktionov, K. V. (1993). Life Cycles of Trematodes as Components of Ecosystems. Kola Scientific Centre of the Russian Academy of Sciences Press, Apatity (in Russian).

Galaktionov, K. V. (1995). Long-term changes in the helminth fauna of colonial seabirds in the Seven Islands archipelago (Barents Sea, Eastern Murman). In: Ecology of Fjords and Coastal Waters (ed. Skjolda, H. R., Hopkins, C., Erikstad, K. E. and Leinaas, H. P.), pp. 489-496. Elsevier Science, Amsterdam.

Galaktionov, K. V. (1996). Life cycles and distribution of seabird helminths in the Arctic and sub-Arctic regions. Bulletin of the Scandinavian Society for Parasitology 6 (2), 31-49.

Galaktionov, K. V. (2009). Description of the maritae and determination of the species status of Microphallus pseudopygmaeus sp. nov. (Trematoda: Microphallidae). Parazitologiya 43: 289-299 (in Russian).

Galaktionov, K. V., Marasaev, S. F. and Marasaeva, E. F. (1993). Parasites in maritime ecosystems. In Environment and Ecosystems of the Franz Josef Land (Archipelago and Shelf) (ed. Matishov, G. G.), pp. 213-221. Kola Scientific Centre Press, Apatity.

Galaktionov, K. V., Regel, K. V. and Atrashkevich, G. I. (2010). Microphallus kurilensis sp. nov., a new species of microphallids from the “pygmaeus” species group (Trematoda, Microphallidae) from the coastal areas of Okhotsk and Bering Seas. Parazitologiya 44, 496-507 (in Russian).

Galaktionov, K. V., Kuklin, V. V., Ishkulov, D. G., Galkin, A. K., Marasaev, S. F., Marasaeva, E. F. and Prokofiev, V. V. (1997). On the helminths fauna of birds from the coast and islands of Eastern Murman (the Barents Sea). In Ecology of Birds and Seals in the Seas of the Northwestern Russia (ed. Matishov, G. G.), pp. 67–153. Kola Scientific Centre of the Russian Academy of Sciences Press, Apatity (in Russian).

Garden, E. A., Rayski, C. and Thom, V. M. (1964). A parasitic disease in eider ducks. Bird Study 11, 280-287.

Grytner-Ziecina, B. and Sulgostowska, T. 1978.Trematodes of Oedemia fusca (L.), Oedemia nigra (L.) and Somateria mollissima (L.) from the Baltic Coast. Acta Parasitologica Polonica 25, 121-128.

Irwin, S. W. B. and Prentice, H. J. (1976). The parasitic fauna in the digestive tracts of three herring-gulls, Larus argentatus, Taken from Strangford Lough. Irish Natur J; 18: 281-82

James, B. L., Sannia, A. and Bowers, E. A. (1977). Parasites of birds and shellfish. In: Problems of a Small Estuary. Proceedings of the Symposium on the Burry Inlet (South Wales). 13-15 September 1976 Jointly by West Glamorgan County Council and the University College’s Institute of Marine Studies (ed. Nelson-Smith, A. and Bridges, E. M.). Sess 6, paper 1, pp. 1-16. Quadrant Press Ltd., Swansea.

Krasnov, Yu. V., Matishov, G. G., Galaktionov, K. V. and Savinova, T. N. (1995). Colonial Seabirds of Murman. Nauka, St. Peterburg (in Russian)

Kuklin, V. V. and Kuklina, M. M. (2005). Helminthes of Birds of the Barents Sea: Fauna, Ecology and Influence on the Hosts. Kola Scientific Centre of the Russian Academy of Sciences Press, Apatity (in Russian).

Kulachkova, V. G. (1958) Ecological-faunistic review of parasite fauna of common eider of the Kandalaksha Gulf. Proceedings of the Kandalaksha State Natural Reserve 1, 103-160 (in Russian).

Kulachkova, V. G. (1979). Helminths as a cause of common eider's death in the top of Kandalaksha Gulf. In Ecology and Morphology of Eiders in the USSR (ed. Uspenskiy, S. M.), pp. 119-125. Nauka, Moscow (in Russian).

Odhner, T. (1905). Die Trematoden des Arktischen Gebietes. Fauna Arktica 4, 291-372.

Person, L., Borg, K. and Falt, H. (1974). On the occurrence of endoparasites in eider ducks in Sweden. Swedish Wildlife 9, 1-24.

Pemberton, R. T. (1963). Helminth parasites of three species of British gulls, Larus argentatus Pont., L.fuscus L. and L.ridibundus L. Journal of Helminthology 37, 57-88.

Threlfall, W. (1967). Studies on the helminth parasites of the herring gull, Larus argentatus Pontopp., in northern Carnarvonshire and Anglesey. Parasitology 57, 431-453

Threlfall, W. (1968). Studies on the helminth parasites of the American herring gull (Larus argentatus Pont.) in Newfoundland. Canadian Journal of Zoology 46, 1119-1126.

Tsimbaljuk, A. K., Kulikov, V. V. and Baranova, T. I. (1968). On the biology of Microphallus calidris Belopolskaia et Ryjikov, 1963 (Trematoda: Microphallidae). In Helminths of animals of the Pacific Ocean (ed. Skrjabin, K. I. and Mamaev, Yu. L.), pp. 125-128. Nauka, Moscow (in Russian).

Yamaguti, S. (1958). Systema Helminthum. Vol.1. The Digenetic Trematodes of Vertebrates. Interscience, New York.