Amnicythere ex. gr. multituberculata (Livental, 1929)

Fig. 20 a-h

1929 Cythere multituberculata nov. sp. - Livental, p. 14, pl. 1, figs. 36–38.

1962 Cythere multituberculata Livental- Mandelstam et al., p. 299, pl. 37, fig. 6.

1972 Leptocythere multituberculata Livental- Sokač, p. 71, pl. 32, fig. 14-15.

1973 Leptocythere (Amnicythere?) multituberculata (Liv.) - Krstić, p.86; text-fig. 116; pl.III, fig. 8.

1986 Leptocythere multituberculata (Livental) - Yassini, p. 27, pl. 10, fig. 1-3.

1989 Leptocythere (?) multituberculata (Livental) - Olteanu, pl. VI. fig. 5-6.

1995 Amnicythere multituberculata (Livental) - Olteanu, p.345, pl. XVI, fig. 1-8.

2011 Leptocythere (Amnicythere) multituberculata (Livental) - Olteanu, p. 159, pl. IX, fig.5.

2013 Amnicythere multituberculata (Livental) - Van Baak et al., p. 124, fig. 4, 16.

2016 Amnicythere multituberculata (Livental) - Van Baak et al., p. 67, fig. 4a, 9-10.

Description. The species has an elongated shape and four large tubercles and, in some cases, a slightly inflated posterior area. The tubercles as well as the interspaces between them are covered with a more or less pronounced but distinct wide-sized mesh pattern that fades towards the anterior end. In some rare cases the primary reticulation is filled with a secondary, finer ornamentation. The dorsal margin is almost straight, inclining slightly towards the posterior and passing smoothly onto the rounded anterior border in an obtuse angle. The transition onto the anterior border forms a ledge through the “hinge ear”. Both anterior-and posterior borders merge smoothly with the ventral margin, which is antero-medially concave. Both, along the anterior-and posterior margin a number of irregular distributed small sized conulus pores are present. The hinge is typical for the genus and is pronounced as a smooth median bar. In adults, the inner lamella is well developed both anteriorly and posteriorly and along the ventral margin. Dimension: L = 0,61 – 0,68 mm, H = 0,33 – 0,35 mm, the minimum sizes include juveniles too.

Remarks. The species shows a large variation in ornamentation, possibly induced by environmental fluctuations.

Chronostratigraphical and geographical distribution. The species is described from the Pontian of Bulgaria and inside the Pannonian Basin at the lower Pontian level (Sokač, 1972). In the Dacian Basin it appears in the Bosphorian (late Pontian), reaching a maximum frequency at the Getian (early Dacian) time. It occurs only sporadically in the Parscovian (late Dacian; Olteanu, 1995). It has further been mentioned from the Pontian of the Bădislava – Topolog area in Romania (Floroiu et al., 2011). Inside the Eastern Paratethys L. multituberculata is widely present in South Caspian basin: from the Pontian (Adzhiveli section) and Akchagylian – Aspheronian deposits (Goychay and Hajigabul sections) of Azerbaijan (Van Baak et al., 2013, 2016; Lazarev et al., 2019) and from Aspheronian of Turkmenistan (Agalarova et al., 1961; Mandelstam et al., 1962; Yassini, 1986). It is also known from the Pontian of the Taman Peninsula in Russia (Stoica et al., 2016), successions of Pontian age in the eastern Black Sea region of Turkey (Tunoğlu and Ünal, 2001) and Lago Mare (late Messinian) deposits of Italy and Sicily (Gliozzi et al., 2005; Grossi et al., 2015).

Ecology. L. multituberculata has been mentioned by Grossi et al. (2015) as part of a “ Cyprideis-Loxoconchidae assemblage”, representing low mesohaline and shallow water conditions. Living representatives of the species were described by Gofman (1966), Yassini (1986) and Gliozzi and Grossi (2008) throughout nowadays remnants of the Paratethys (Black Sea, Caspian Sea, Aral Sea) at salinities of 11,5 – 18,25‰.