Ladislavella B. Dybowski, 1912

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 : 12

Genus Ladislavella B. Dybowski, 1912 s.s.

Dybowski 1912: 179.

Type species: Ladislavella sorensis B. Dybowski, 1912 = Limnaea palustris var. terebra Westerlund, 1885 (by subsequent designation).

Diagnosis: Shell of typical ‘stagnicoline’ shape, tall and slender, with high spire and weakly inflated body whorl. Its size is typically not larger than 22 mm. Shell shape varies from high-turriculate to high-conical. Prostate with a single fold inside. The penial knot is absent. Praeputium is dark-pigmented, slender and relatively narrow; its width slightly exceeds the width of the penis sheath ( Fig. 4D ). The lengths of the praeputium and penis sheath are almost equal; the distal part of the latter is somewhat swollen.

Species richness: Four or five species, one of them, Ladislavella liogyra ( Westerlund, 1897) , occurs within the studied region. It is characterized by a very slender turriculate shell ( Fig. 3E ); the number of whorls can reach 7.5–8.0. There are no similar species in East Asia.

Distribution: The genus is distributed from Central and East Europe eastwards to the southern part of the Russian Far East (the middle and lower courses of the Amur River, Primorye, and Sakhalin Island).

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).