Lymnaea (Stagnicola) gloeeri, Vinarski, Maxim V., 2011

Vinarski, Maxim V., 2011, A new species of stagnicoline snails (Mollusca: Gastropoda: Lymnaeidae) from the extreme North of Western Siberia, Zootaxa 2817, pp. 55-58 : 55-57

Lymnaea (Stagnicola) gloeeri sp. nov.

(Fig. 1, M–R, Table 1 )

Type locality. Russia, Tyumen Region, Ra-Iz Ridge (Polar Urals), small artificial pond lying at the base of the railway embankment at kilometer 141 of the Labytnangi–Seida railroad (approximate coordinates: 6650 N, 6540 E).

Type material (all from the type locality). Holotype and 5 paratypes in the Zoological Institute of the Russian Academy of Sciences, Sankt-Petersburg ( ZIN 1). 9 paratypes ( MSAM 15-1493, 15-2048).

Other material studied. 7 specimens from the type locality in Senckenberg Naturhistorische Sammlungen Dresden, Germany ( SNSD 52882–52887).

Shell description. Shell turriculate-conical, solid, light-brown, medium-sized (height up to 22.5 mm). Whorls number up to 7.0. Whorls strongly inflated, sometimes almost stepped, separated by deep, oblique suture. Spire conical, tangent line slightly convex. Body whorl moderately inflated, relatively high, its surface covered by growth lines and (in some shells) weakly malleated. Aperture ovate, columellar fold weakly developed. Columellar lip narrow, thin, completely covering the umbilicus. Protoconch usually corroded with 1.0–1.5 initial whorls being destroyed.

1. I use the term ‘stagnicoline snails,’ or ‘stagnicolines,’ for the designation of an informal and clearly polyphyletic group of lymnaeid species corresponding to the species Lymnaea palustris ( O.F. Müller, 1774) sensu Hubendick (1951) . It has a wide Holarctic distribution and includes at least two independent clades of Palaearctic and Nearctic origin, respectively ( Bargues et al. 2006).

FIGURE 1. Shells and reproductive organs of stagnicoline species from the north part of Western Siberia. A–C. L. ventricosella ( MSAM 15-1945). D–E. L. saridalensis ( MSAM 15-2080). F–G. L. terebra ( MSAM 15-1794). H–I. L. palustris ( MSAM 15-1249). J–L. L. zebrella ( MSAM 15-1970). M–R. L. gloeeri sp.n. ( ZIN 1), M holotype, N– O paratypes, P internal section of the prostate, Q proximal part of the female genitals, R copulative organs). Scale bars: 1 mm (A, B, F, G, P–R), 2 mm (D, F, H, M– O). The arrows indicate the positions of praeputium (pp) and penis sheath (ps). E after Andreeva et al. (2010). Photos P–R by P. Glöer.

Anatomical traits (8 largest specimens ( ZIN 1; MSAM 15-2048) dissected). Prostate with a single internal fold. Spermathecal duct very long and narrow, roughly 3 times as long as the spertmatheca. Uterus long and narrow, its width nearly constant along the full length. Praeputium greyish-white, cylindric, its width constituting approximately 0.40– 0.45 of its length. Penis sheath of nearly same size as praeputium, narrow, yellowish-white, with a distinct bulbous buldge on its proximal end. ICA (“index of the copulative apparatus = ratio between lengths of praeputium and penis sheath) varying from 0.81 to 1.08 (see Table 1 ).

Specimen Whorl count ICA Standard shell measurements, mm

Differential diagnosis. L. gloeeri sp.n. can be distinguished from all other stagnicoline species of the north part of Western Siberia by its strongly inflated whorls. From L. saridalensis and L. ventricosella that also have somewhat convex whorls it differs by its much shorter penis sheath that is comparable in size with the praeputium (compare Figs. 1C, E and Fig. 1R).

Distribution. The species is known from the type locality only. So far it is the only lymnaeid species found in the moutains of the Polar Urals region and, possibly, it is more widely distributed in the water bodies of this region.

Etymology. This species is dedicated to Peter Glöer, a German malacologist, who made a large contribution to our knowledge of Siberian freshwater snails. His friendly assistance in my research is invaluable; among other things, he made excellent photos of the genitals of the species named in his honour.

Tables

TABLE 1. Morphometric characteristics of the type series of L. gloeeri sp. n. AH—aperture height; AW—aperture width; BWN—body whorl height; ICA— index of the copulative apparatus; SH—shell height; SpH—spire height; SW— shell width. * Shell apex corroded; ** Not measured. Intact, ethanol-preserved paratypes in ZIN.

	SH	SW	SpH	BWH AH	AW
holotype 6.00 1 [ZIN 1] 6.50	0.99 17.3 1.01 20.4	8.1 8.4	10.6 12.9	11.6 6.8 12.4 7.6	5.5 5.8
2 [ZIN 1]?*	1.04 16.6	8.4	10	11.3 6.8	5.3
3 [ZIN 1] 5.75 4 [ZIN 1] 6.75	1.08 15.4 –** 21.9	7.3 8.9	9.4 14.2	10.0 6.2 13.1 7.1	4.4 6.1
5 [ZIN 1] 7.00	–** 21.5	9.0	12.7	13.8 8.0	6.0
6 [MSAM 15-1493] 6.75 7 [MSAM 15-1493] 6.25	1.09 22.3 0.81 17.5	8.7 8.3	13.1 10.6	14 6.3 12 7.2	5.0 5.5
8 [MSAM 15-1493] 6.50	0.93 17.3	7.5	11	11.2 6.5	5.4