Tyrrhenocythere sp.

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 : 29

Tyrrhenocythere sp.

Fig. 18 a-k

Description. The carapace has a rectangular to oblongoval shape in lateral view and a distinct eye spot at the anterodorsal corner. The male valves are slightly longer and show almost parallel running dorsal-and ventral margins, while female valves tend to be shorter with a dorsal margin slightly sloping towards the posterior. The anterior margin is broadly rounded and passes smoothly onto the ventral end. In the anterior third, the ventral margin shows a concavity more visible on the RV. The posterior end bears a more or less pronounced shoulder, mainly visible on RV, and is rounded underneath. Above, it continues slightly concave onto the almost straight running dorsal margin. The outer margin of the carapace is surrounded by a fine rim that stretches from the anterior end along the entire ventral margin and stops in the middle of the posterior end. There it is extending onto the shoulder and broadens it. The valves surface is covered with small to medium sized pits. Towards the posterior-and the anterior end the ornamentation is turning into medium-sized longitudinally running meshes. The marginal zone is broad, especially along the anterior margin, and displays a number of branched pore channels. The muscle scar consists of two rows of imprints, owing to the division of the two median imprints into upper and lower ones. The hinge is well developed and heterodont with a strong single posterior-and anterior tooth. Dimension: L = 0,44 – 1,12 mm, H = 0,27 – 0,58 mm, the minimum sizes include juveniles too.

Remarks. Tyrrhenocythere bailovi (Livental) in Mandelstam et al., 1962, described from the Caspian region (Yassini, 1986), displays a similar type of ornamentation but with finer and closer arranged pits and without the medium-sized parallel running meshes at the anterior-and posterior end. Also, the outline of T. bailovi is more pointed towards the posterior in both males and females and we therefore renounce the assigning of this species.

Figures

Fig. 18a-k Tyrrhenocythere sp. a LV, external view, ♂; b RV, external view, ♂; c, g LV, external view, ♀; d, h RV, external view, ♀; e RV, internal view, ♂; f RV, internal view, ♀; i LV, external view, A1 juvenile; j LV, external view, A2 juvenile; k LV, external view, A3 juvenile; (all specimens from section B, samples 19 m and 23 m).