Rissoa clotho Hörnes, 1856

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 : 58

Rissoa clotho Hörnes, 1856

Fig. 2b

1856 Rissoa clotho sp. nov. - Höernes, p. 574, pl. 48, fig. 20 a,b

1975 Turboella (Turboella) clotho (Hörnes) - Bałuk, p. 70, pl. 8, fig. 8

2004 Rissoa clotho Hörnes - Kowalke and Harzhauser, p.117, fig. 4D

Material: 13 specimens, five from L5, four form Lp2, one from Lp3and three from Lp10 (one specimen PMBBU 23851 )

Description: Conical-elongated shell consisting of six whorls reaching up to 3 mm in height and 1.5 mm in width. The protoconch is build-up of 2.25 convex whorls. The teleoconch displays convex whorls separated by an incised suture. Ornamentation consists of prominent axial ribs that become more convex over the suture. On the last whorls, in their lower half, one can notice fine spiral threads, more obvious on the last whorl. This latter represents about 55% of the total shell height and is ornamented with 12 axial ribs. Oval aperture, the inner lip covers the umbilicus while the external lip displays varices.

Distribution: identified in Austria ( Kowalke and Harzhauser, 2004), Poland ( Bałuk, 1975).

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).