1. Radix (Radix) auricularia (Linnaeus, 1758) Figs 3A; 4A.

Helix auricularia Linnaeus 1758: 774, 775.

Lymnaea auricularia - Hubendick 1951: 151, figs 96, 97, 99 (partim).

Lymnaea (Radix) auricularia - Kruglov and Starobogatov 1993a: 85, fig. 10E; Jackiewicz 1998: 47, figs 64, 65, pl. II, X.7, XI, 1, 2; Kruglov 2005: 250, figs 137(1)-139; Andreeva et al. 2010: 99, fig. 48.

Lymnaea (Radix) hadutkae Kruglov and Starobogatov 1989: 22, figs 1(12), 2(7); 1993a: 85, fig. 11D.

Lymnaea (Radix) hakusyensis Kruglov and Starobogatov 1989: 20, figs 1(8), 2(6); 1993a: 88, fig. 11G.

Lymnaea (Radix) thermobaicalica Kruglov and Starobogatov 1989: 20, figs 1(10), 2(8); 1993a: 85, fig. 11E.

Lymnaea (Radix) thermokamtschatica Kruglov and Starobogatov 1989: 22, figs 1(9), 2(9); 1993a: 85, fig. 11F.

Radix auricularia - Glöer 2002: 213, fig. 241; Welter-Schultes 2012: 52, textfig; Vinarski and Kantor 2016: 318; Aksenova et al. 2016: 16, figs 1F, G; 2; Glöer 2019: 236, fig. 294.

TL.

Europe.

Types.

Possibly lost (Vinarski and Kantor 2016).

This species is common in Eurasia, sporadically distributed in North Africa, introduced into North America and New Zealand (Hubendick 1951; Charleston and Climo 1979; Burch 1989; Brown 1994; Kruglov 2005; Andreeva et al. 2010). It has many times been characterised in literature, both conchologically and anatomically (Jackiewicz 1998; Glöer 2002; Kruglov 2005). The typical form of this snail has an ear-shaped shell with shortened spire and greatly expanded body whorl (see Fig. 3A). However, R. auricularia exhibits wide variation is shell shape and proportions (Vinarski 2016b). It may form local and ecological races, including dwarf races of geothermal springs, which had been accepted as valid species (Bolotov et al. 2014; Aksenova et al. 2016, 2017).

The structure of the copulatory apparatus of R. auricularia is quite typical for the genus. The praeputium is oblong, cylindrical and rather thick; its width is virtually equal along its whole length (see Fig. 4A). The penis sheath is much narrower, with a bulbous swelling on its distal end. The lengths of the praepuptium and the penis sheath of R. auricularia are nearly equal, though in some populations, there is a substantial variation in the ICA values (Vinarski 2011).

A characteristic trait of this species, which distinguishes it from the remaining radicines of Europe, is the presence of freckles on the foot and praeputium ( Glöer 2019).