Walhiana Servain, 1882

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 : 12-13

Genus Walhiana Servain, 1882

Servain 1882: 55.

= Walterlymnaea Starobogatov & Budnikova, 1976 syn. nov.

Type species: Lymnaea vahlii MØller, 1842 = Lymnaea catascopium (by original designation) ( Servain 1882).

Diagnosis: Shell medium in size; shape varies from high-turriculate to high-conical (almost ear-shaped forms are known as peculiar ‘ecological races’; see Walter 1969). Most species have a ‘stagnicoline’ appearance, i.e. slender, high-spired shells with a relatively small aperture. The number of whorls can reach six or seven. The structure of the copulatory apparatus is identical to that of Dallirhytis . Prostate with a single fold inside. Penial knot present.

Species richness: Uncertain, owing to a large number of nominal species accepted as valid (see Burch 1989, Johnson et al. 2013) but not yet studied genetically. The genus might include ≤10 accepted species. Two species are recognized in the study region: Walhiana arctica (I. Lea, 1864) ( Fig. 3F) and Walhiana catascopium (Say, 1817) ( Figs 3G, H, 4E). The former ( Fig. 3F) is confined to the northern Nearctic, occurring in Alaska and Northern Canada through to Newfoundland ( Baker 1911, Burch 1989, Johnson et al. 2013). The two species are virtually indistinguishable from each other both conchologically and anatomically. However, Clarke (1973) noted that W. arctica is characterized by smaller size (shell height not exceeding 22 mm, with six whorls or more) and a wide and thick columella. Walhiana catascopium is extremely variable and widely distributed, known from the North American mainland (south to Mexico), Kamchatka, and Greenland ( Clarke 1973, Burch 1989, Vinarski et al. 2016, 2017a).

Distribution: Extreme northeast Asia (Chukchi and Kamchatka peninsulas), North American mainland south to Mexico, and Greenland.

Remark: Walhiana Servain, 1882 is the oldest available name for this group. The names Walterlymnaea Starobogatov & Budnikova, 1976 and Catascopia Meier-Brook & Bargues, 2002 are junior synonyms (see Vinarski 2012).