Acteocina lajonkaireana (Basterot, 1825)

Frolov, Pavel D., Danukalova, Guzel A. & Osipova, Eugenia M., 2018, Late Miocene molluscs of the Morskaya 2 site (Azov Sea region, Russia), Palaeontologia Electronica (a 20) 23 (1), pp. 1-32 : 11

Acteocina lajonkaireana (Basterot, 1825)

Figure 4.1 , Figure 7.7

1825 Bulla lajonkaireana Basterot , p. 22, pl. 1, fig. 25.

1856 Bulla lajonkaireana Basterot ; Hörnes, partim, p. 624, pl. 50, figs. 9c-9d.

1911-1928 Tornatina lajonkaireana (Basterot) ; Friedberg, p. 542, pl. 35, fig. 16.

1935 Bulla lajonkaireana Basterot ; Kolesnikov, p. 285-286, pl. 33, figs. 1-4.

1936 Tornatina lajonkaireana (Basterot) ; Zhizhchenko, p. 266, pl. 25, figs. 15-18, 27-30, pl. 26, figs. 3, 4.

1953 Acteocina lajonkaireana lajonkaireana (Basterot) ; Berger, p. 104, pl. 17, figs. 54- 61.

1976 Acteocina lajonkaireana (Basterot) ; Iljina, Nevesskaya and Paramonova, p. 276, pl.

28, figs. 22-24.

1987 Acteocina lajonkaireana (Basterot) ; Yanakevich, p. 96, pl. 7, figs. 17, 18.

1993 Acteocina lajonkaireana (Basterot) ; Iljina, p. 122, pl. 15, figs. 11-14.

Material. 12 specimens from layer 1 and 46 specimens from layer 3.

Description. Oval-cylindrical shell with a pointed spire (usually HS is up to 7 mm; WS is up to 3.5 mm), may be slightly larger (WS/HS is 0.5), consists of 4.5 whorls separated by a horizontal moderately deep suture. Protoconch is heterostrophic. Spire has a wide conical form; whorls are slightly convex. There is a well-defined groove in front of the suture on 1.5-2 last whorls. The last whorl is rounded, about 0.9 of the total shell height (HLW/ HS). Aperture is slit-shaped, widens to the bottom part and becomes rounded; HA/HS is 0.85. The aperture outer edge is thin; the inner one is tightly adjacent to the whorl, forming a well-visible thickening. The shell surface is smooth; growth lines are visible.

Remarks. Samples from layer 3 are represented mainly by internal casts.

Region of distribution and age. Early Miocene. Europe, North Caucasus, Transcaucasia (Iljina, 1993).

Figures

FIGURE 4. Assemblage of the Middle Sarmatian (Bessarabian) marine gastropods (layers 1 and 2). 1, Acteocina lajonkaireana (Basterot, 1825). 2, Acteocina okeni (Eichwald, 1850). 3, Retusa melitopolitana (Sokolov, 1899). 4, Hydrobia elongata Eichwald, 1830. 5, Pseudamnicola nympha (Eichwald, 1850). 6, Dorsanum duplicata opinabile (Kolesnikov, 1932). 7, Dorsanum corbiana (d’Orbigny, 1844). 8, Dorsanum ignobile (Kolesnikov, 1932). 9, Gibbula (Gibbula) pseudoangulata (Sinzov, 1875). 10, Gibbula (Sarmatigibbula) podolica (Du Bois de Montpéreux, 1831).

FIGURE 7. Assemblage of the redeposited Miocene marine and terrestrial molluscs. 1, Vertigo sp. 2, Hydrobia enikalensis Kolesnikov, 1935. 3, Hydrobia elongata Eichwald, 1830. 4, Gibbula sp. 5, Gibbula (Sarmatigibbula) podolica (Du Bois de Montpéreux, 1831). 6, Gibbula sp. 7, Acteocina lajonkaireana (Basterot, 1825).