Bythinella golemoensis, Glöer & Mrkvicka, 2015

Glöer, Peter & Mrkvicka, Alexander C., 2015, New taxa of freshwater snails from Macedonia (Gastropoda: Hydrobiidae, Amnicolidae), Ecologica Montenegrina 3, pp. 13-18 : 16-17

Bythinella golemoensis n. sp.

( Figs 11-18 )

Type series: Holotype: shell height 2.7 mm, width 1.6 mm, NHMW Mollusca 111204 ; Paratypes: (i): spring SW of Golemo Lake, 22 specimens in ethanol NHMW Mollusca 111205, 3 specimens in coll. Glöer, (ii): spring E of Golemo Lake , 7 specimens in ethanol NHMW Mollusca 111256 .

Locus typicus: spring SW of Golemo Lake , Pelister National Park, Macedonia. (40°58'08.31"N 21°12'25.16"E; altitude 2218 m)

Etymology: Named after the Lake near the springs where this species occurs.

Description

Shell. Shell cylindrical with 4.5 convex whorls with a moderately deep suture. The whorls are fast growing. Apex obtuse, umbilicus closed. Aperture oval. Shell height 2.7-2.9 mm, width 1.6–1.7 mm, aperture height to shell height ratio 0.39-0.44.

Soft body. Mantel black with a white border, tentacles long and thin.

Morphology of the penis. Penis as long as the penial appendix, flagellum relative short and regularly thick.

Differentiating features: From Bythinella drimica drimica , it differs in shell morphometry: shell height 1.97-2.31 in B. d. drimica vs. 2.7-2.9 mm in B. golemoensis n. sp., and shell width 1.13-1.30 in B. d. drimica vs. 1.6-1.7 mm in B. golemoensis n. sp. (measurements of B. d. drimica after Radoman 1983). The umbilicus in B. d. drimica is slit-like, closed in B. golemoensis n. sp. From B. melovskii it differs in aperture height to shell height ratio which is in B. melovskii 0.44-0.47 and 0.39-0.44 in B. golemoensis n. sp. In addition the penis is longer than in B. melovskii while the tubular gland is shorter.

Habitat and ecology: The cold springs where B. golemoensis lives are situated at the foot of a natural dam and fed by the lake, which is situated above the dam. The water emerges from the base of the dam at about 120 m length. Vegetation is like in alpine springs with abundant growth of mosses on and between stones. Living B. golemoensis were found on and under stones. Water temperature was about 8°C in July. In Bulgaria Bythinella spp. could not be found above 2000 m alt.

Distribution: Only found in cold springs near Golemo Ezero (“Large Lake”) in NP Pelister, Rep. Macedonia.

Figures

Figures 11-14. Bythinella golemoensis n. sp. 11: shell of holotype; 12: shell of paratype from (2); 13: head and penis in situ; 14: penis with tubular gland (flagellum).

Figures 15-18. Bythinella golemoensis n. sp. 15: shell of holotype; 16: shell of paratype from (2); 17: head and penis in situ; 18: penis with tubular gland (flagellum).