Taxonomy and trans-Beringian biogeography of the pond snails (Gastropoda: Lymnaeidae) of East Asia: an integrative view

In this work, we present an integrative revision of the Lymnaeidae from the northeastern margin of Asia (Far East Russia, Japan, and Korea) and Alaska. According to our results, 14 native species inhabit this region, belonging to eight genera in two subfamilies (Lymnaeinae: Dallirhytis, Galba, Walhiana, Ladislavella, and Lymnaea; and Amphipepleinae: Kamtschaticana, Orientogalba, and Radix). Four of these species are new to science and three of them are described in this paper. Additionally, three established alien species are recorded from Japan (Pseudosuccinea columella, Galba schirazensis, and Galba humilis). The Japanese Archipelago represents an evolutionary hotspot of pond snail diversity, encompassing seven native species, three of which are endemic. The faunal connections between North America and northeastern Asia are discussed in the context of historical biotic interchange across the Beringian Land Bridge. Two cold-tolerant pond snails share high-latitude but localized ranges, being endemic to the Beringian Arctic: Dallirhytis atkaensis (Chukchi Peninsula, Alaska, and Aleutian Islands) and Walhiana arctica comb. nov. (Alaska). Our findings indicate that the Beringian Land Bridge has played a role in freshwater faunal exchanges between northeastern Asia and western North America.