Lymnaeinae Rafinesque, 1815

Aksenova, Olga V., Vinarski, Maxim V., Itagaki, Tadashi, Ohari, Yuma, Oshida, Tatsuo, Kim, Sang Ki, Lee, Jin Hee, Kondakov, Alexander V., Khrebtova, Irina S., Soboleva, Alena A., Travina, Oksana V., Sokolova, Svetlana E., Palatov, Dmitry M., Bespalaya, Yulia V., Vikhrev, Ilya V., Gofarov, Mikhail Yu. & Bolotov, Ivan N., 2024, Taxonomy and trans-Beringian biogeography of the pond snails (Gastropoda: Lymnaeidae) of East Asia: an integrative view, Zoological Journal of the Linnean Society 201 (4), pp. 1-24 : 5-12

Subfamily Lymnaeinae Rafinesque, 1815

Type genus: Lymnaea Lamarck, 1799 .

Genus Dallirhytis Kruglov & Starobogatov, 1989

Kruglov and Starobogatov 1989: 15.

Type species: Lymnaea petersi Dall, 1905 = Limnaea ovata var. atkaensis Dall, 1884 (by original designation).

Diagnosis: Shell medium in size, ovate-conical to almost ear-shaped, with well-developed acute spire ( Fig. 3A, B ). Whorls are conspicuously inflated. Praeputium cylindrical, oblong, dark-pigmented; penis sheath rather short and compact; its length is 2.5–3.0 less than the praeputium length ( Fig. 4A ). Penis with a

(rudimentary) ring-shaped fixing swelling [ Walter (1969) calls it the ‘penial knot’]; prostate with a single internal fold.

Species richness: This is a monotypic genus. In addition to Dallirhytis atkaensis, Kruglov and Starobogatov (1989 , 1993) listed another species, Lymnaea petersi Dall, 1905 . However, we synonymize both species based on examination of samples of Ly. petersi kept in ZIN. We found that the conchological variability of Ly. petersi falls within the range of variability of D. atkaensis . The ranges of both taxa as accepted byKruglov and Starobogatov (1993) overlap almost completely. Dallirhytis atkaensis has a very characteristic shell appearance and can hardly be confused with another pond snail species of Beringia.

Distribution: A Beringian taxon known from Alaska, the Yukon Territory, northern British Columbia, and the Chukchi Peninsula ( Burch 1989, Kruglov 2005, Aksenova et al. 2023).

Figures

Figure 3. Shells of the Lymnaeinae species. A, Dallirhytis atkaensis (USA, Alaska, Birch Lake; RMBH). B, Dallirhytis atkaensis (Russia, the Chukchi Peninsula, an unnamed lake; ZIN). C, Galba sibirica (Mongolia, the Teellin-gol River; after Vinarski et al. 2017b). D, Galba truncatula (Russia, Irkutsk Region, vicinities of Kirensk Town; LMBI). E, Ladislavella liogyra (Russia, Amur basin, vicinities of Nikol’sk-Ussuriysky Town; ZIN). F, Walhiana arctica (Canada, Ontario, Hudson’s Bay; NHMUK). G, Walhiana catascopium (Canada, British Columbia, Aintworth hot springs; RMBH). H, Walhiana catascopium (Russia, Kamchatka, Azabachye Lake; RMBH). I, Lymnaea jugularis (USA, Michigan, the Rouge River; NHMUK). J, Lymnaea sorensis (Russia, Lake Baikal, a syntype; ZIN). K, Lymnaea jugularis (USA, Minnesota, a neotype with label; ZIN). Scale bars: 2 mm in C, D, F–H; 5 mm in A, B, E, I–K.Photographs: Maxim V.Vinarski (A–F, I–K) and Olga V.Aksenova (G, H).

Figure 4. The copulatory apparatuses of the pond snails discussed in the taxonomic account. A, Dallirhytis atkaensis (Russia, the Chukchi Peninsula, Lake Vaaliuchio). B, Galba sibirica (Mongolia, the Teellin-gol River; after Vinarski et al. 2017b). C, Galba truncatula (Abkhazia, Gagra District, wet shore of Inkit Lake; after Vinarski et al.2017b). D, Ladislavella liogyra (Russia, Primorye, a pool near Lake Lebedinoye).E, Walhiana catascopium (Russia, Kamchatka, Azabachye Lake; RMBH). F, Lymnaea sorensis (Russia, Kamchatka, Kamchatka River; RMBH). G, Kamtschaticana kamtschatica (Russia, Magadan Region, a water reservoir; after Vinarski et al. 2021). H, Orientogalba ollula (Russia, Primorye Territory, near Possiet Settlement; after Kruglov 2005). I, Radix auricularia (Russia, Tyumen’ Region, Vylposl channel near Labytnangi Town). J, Radix plicatula (China, Bejing, an artificial pond in the former Emperor’s summer palace; after Vinarski et al. 2020). K, Radix cf.hamadai (Japan, Matsumae; after Vinarski et al. 2020). Scale bars: 1 mm.Photographs: Maxim V. Vinarski (A–D, G, I–K) and Olga V. Aksenova (E, F).