Alvania (Alvania) helenae Boettger, 1901

TĂMAȘ A., TĂMAȘ D. M. & POPA M. V., 2013, Badenian Small Gastropods From Lăpugiu De Sus (Făget Basin, Romania). Rissoidae Family, Acta Palaeontologica Romaniae 9 (1), pp. 57-66 : 61

Alvania (Alvania) helenae Boettger, 1901

Fig. 2h

1901 Alvania (Alvania) helenae n. sp. - Boettger, p. 140, nr. 432

1934 Alvania (Alvania) helenae Boettger - Zilch, p. 211, pl. 5, fig 81

1975 Alvania (Alvania) helenae Boettger - Bałuk, p. 81, pl. 9, fig. 10

Material: four specimens from L5 (one specimen PMBBU 23857 )

Description: Elongated conical shell with 5 whorls; up to 2.75 mm in heights and 1.63 mm in width. Protoconch consisting of about two convex whorls ornamented with spiral threads. Teleoconch with convex whorls ornamented with pronounced axial ribs intersected by finer spiral threads; knots form at the intersection. The last-but-one whorl shows one varix. The last whorl represents 65–70% of the total shell height; ornamented with 14-18 axial ribs intersected by 6 spiral threads. Towards the base, four additional spiral threads are noticeable. Drop-like aperture, with the inner lip covering the umbilicus. External lip with inner denticles and external varix.

Distribution: identified in Poland ( Bałuk, 1975), Romania ( Boettger, 1901; Zilch, 1934).

Figures

Fig. 2 - a Rissoa acuticosta (Sacco, 1895). b Rissoa clotho Hörnes, 1856. c Rissoa costeiensis Kowalke & Harzhauser, 2004. d Alvania (Alvania) oceani (d'Orbigny, 1852). e Alvania (Alvania) productilis Boettger, 1906. f Alvania (Alvania) perregularis (Sacco, 1895). g Alvania (Alvania) ampulla (Eichwald, 1853). h Alvania (Alvania) helenae Boettger, 1901. i Alvania (Alvania) transiens (Sacco, 1895).