Loxoconcha babazananica ( Livental, 1929 )

RAUSCH, LEA, STOICA, MARIUS & LAZAREV, SERGEI, 2020, A Late Miocene - Early Pliocene Paratethyan Type Ostracod Fauna From The Denizli Basin (Sw Anatolia) And Its Palaeogeographic Implications, Acta Palaeontologica Romaniae 16 (2), pp. 3-56 : 38-41

Loxoconcha babazananica ( Livental, 1929)

Fig. 25 a-k

1929 Loxoconcha Babazananica nov. sp- Livental, p. 35, pl. 1, fig. 44-45.

1949 Loxoconcha babazananica Liv. - Schweyer, p. 48, pl. VI, fig. 2.

1956 Loxoconcha babazananica Livental- Suzin, p. 67, pl. VI, fig. 8.

2013 Loxoconcha babazananica Livental- Stoica et al., p. 140, pl. 2, fig. 38.

2013 Loxoconcha babazananica Livental- Van Baak et al., p. 124, fig. 4b, 24.

2016 Loxoconcha babazananica Livental- Van Baak et al., p. 603, fig. 8a, 10-13.

Description. The small quadrate and narrowed posteriorly carapace, is covered with a coarsely reticulated to pitted sculpture that becomes finer and smoother towards the marginal area. The species appears rather inflated in the posterior half and bears a distinguishable eye-spot in the anterodorsal corner. The dorsal margin is almost straight with a discreet concavity in the posterior segment. The dorsal margin passes smoothly onto the broadly rounded anterior end at an obtuse angle and onto the narrower rounded posterior end at a less obtuse angle. The ventral margin is slightly convex arcuate and recurving towards the posterior end. The extent of the degree of ornamentation varies between individual specimens. In some cases, the reticulated ornamentation in the posterior end is replaced by weakly pronounced meshes. The internal view reveals the presence of a central muscle scar that is arranged in a vertical row of four adductor scars and a vshaped frontal scar. The hinge is well developed and amphidont, with a strongly crenulated bar and two strongly pronounced toothlets in the anterior- and posterior area of the LV. Dimension: L = 0,41 – 0,59 mm, H = 0,26 – 0,36 mm, the minimum sizes include juveniles too.

Chronostratigraphical and geographical distribution. The species is known from saline – brackish water deposits from the Pliocene - Pleistocene (Babazanan, Lokbatan, Goychay, Hajigabul — Akchagylian, Apsheronian and Bakunian) of the South Caspian Basin (Azerbajian) ( Livental, 1929; Van Baak et al., 2013; Lazarev et al., 2019), the middle Romanian (Pelendavian) of the Slănicul de Buzău section of the Dacian Basin (Van Baak et al., 2015), the upper Pontian of the Ramnicu Sarat and Badislava – Topolog area (South Carpathian Foredeep, Romania) ( Floroiu et al., 2011; Stoica et al., 2013) and is generally widespread from late Miocene to recent throughout the Black -and Caspian Sea region (Van Baak et al., 2015). L. babazananica , in many papers considered as Loxoconcha immodulata Stepanaitys ( Boomer et al., 1996, 2010), is further described from Plio-Pleistocene deposits of Turkmenistan, the Aral Sea and from recent brackish-water assemblages of the Caspian Sea ( Boomer et al., 1996, 2005, 2010). Faranda et al. (2007) placed L. immodulata in the extinct genus Loxoconchissa (Loxocaspia) .

Ecology. The living specimens of L. babazananica inhabit sublittoral environments of the Caspian Sea.

Figures

Fig. 25a-k Loxoconcha babazananica; a, c, g, i LV, external view; b, d, h RV, external view; e, f LV, internal view; j LV, external view, A1 juvenile; k RV, external view, A1 juvenile; (all specimens from section A, samples 0 m – 35,5 m).