SOME SPECIES OF THE GENUS HEMICYTHERIA POKORNY (OSTRACODA, CRUSTACEA) FROM THE UPPER MIOCENE OF SERBIA

The ostracod genus Hemicytheria is very important for biostratigraphy of the caspibrackish deposits of the Pannonian basin. More than twenty species are known from regions of central Serbia and adjacent provinces. Most of them being found in the Pannonian and Pontian sediments (Soka~ , 1972; Kr s t i } , 1985; Rund i} , 1992, 1993, 1997). Herein, three new species are reported for the first time: Hemicytheria setosa n. sp., Hemicytheria carinata n. sp., Hemicytheria portaferrica n. sp.

The genus Hemicytheria is one of the most frequent ostracod genera of the family Hemicytheridae which can be found in the Pannonian and Pontian deposits of Serbia.During the long ‡range biostratigraphic and paleontological investigation of the caspibrackish sediments of Serbia and adjacent areas, several yet unknown fossil ostracod species have been identified.In the first place, it refers to the genus Hemicytheria, Pokorny which is more studied and used for the Upper Miocene biozonation (Rundi}, 1997).Herein, three new Hemicytheria species found in outcrops in the vicinity of Mali Po`arevac as well as in core samples from the boreholes of the Kolubara basin.
Pl. I, Figs.Description.Small, thick ‡shelled trapezoidal carapace.Convexity considerable, highest in the anterior part.Dorsal margin straight or slightly arched, descens obliquely toward the posterior part.Ventral margin straight or slightly concave in the first third.Anterior margin rounded, semicircular.Posterior end perpendicular, at males posteroventraly extended.Margins without denticulations.Surface reticulated.Normal pore canals arranged in the suboval fossae separated with slightly faveolate muri.In the middle of valves, fossae are tiny and shallow.There is clear arched ridge in the eye region, which is continuous with anterior rib.Ventral rib poorly developed.Marginal zone broad.
Hinge holoamphidont.In the anterior part of left valve (LV) there is small alveola, behind it there is triangular tooth which transit into the long, smooth median ridge which ends with small alveola in the posterior part.RV has reverse elements.Hinge of juvenils is poorly developed.Other features same as genus Hemicytheria.
Type level.The Late Upper Pannonian.
Diagnosis.Relatively small, partially reticulated carapace.Along the ventral margin there is thick, elongated wing ‡like ridge rising subvertically from valve.Both ends with denticulations.
Description.Carapace subtrapezoidal.The highest in the anterior part.Main feature is horizontal, thickened ventral ridge, highest in the last third.Dorsal margin straight, descens obliquely toward the posterior end.Ventral margin even, slighty concaved in the anterior part.Anterior end rounded, downwards extended.There is 5 ‡6 short spines.Posterior end subvertical then oblique and transit to explicit posteroventral angle.Posterior rim has a four downwards directed spines, the third one larger.Surface slighty reticulated by large, polygonal fossae.The central anterior and central posterior part with slightly ornamentation.In the middle of valves, there is scarce polygonal fossae and distinct faveolate muri.Rare intramural pores visible.Sculpture undistinct in the marginal areas.Eye tubercle large.In the ventral field, main surface element is linear, curved ridge ‡ carina.It is the highest in the posterior third, segmented; on the upper side thickened.
Hinge holoamphidont.Right valve has a high, strong tooth in the anterior part, behind it there is small alveola which transit to long, median groove.In the posterior part there is small, oval tooth.Left valve has a inverse elements.
Distribution.The Late Upper Pannonian (the last two ostracode biozones, after Rundi}, 1997) and the Lower Pontian rarely.It is rather rare in studied boreholes and outcrops in the Kolubara basin.

Hemicytheria major Soka~
Pl. II, Fig. 3 1972 Hemicytheria major n. sp.‡ S o k a ~, p. 77, Pl.XXXVII, Figs. 4 ‡10 1997 Hemicytheria major Soka ~ ‡ Rundi}, p. 71 ‡72, Pl. 12, Fig. 3 Large, elongated Hemicytheria species with well developed denticulation.It has been recorded from the Upper Pannonian of Serbia, Bosnia and Croatia (Soka~, 1972;Rundi}, 1992Rundi}, , 1997) ) Hemicytheria reticulata Soka~ Pl.II, Figs.Thick ‡walled carapace with a pronounced ventral rib and characteristic net ‡like ornamentation.It is relatively rare species in the Upper Pannonian and Pontian of Serbia, Bosnia, Croatia and Slovenia (Soka~, 1972;Stevanovi} & [kerlj, 1989;Rundi}, 1997).Description: Large, trapezoidal and elongated carapace.On margins inflated, the highest in the first third.The main feature of species is presence of a distinct posterior ridge.In the left valve, it is placed obliquely from the posterodorsal angle towards ventral margin.In the right valve, it is firstly subvertical then curved to the central part of valve and it is slighty parallel to the posterior margin.Distance between posterior ridge and posterior margin is about 0.17 ‡0.19 mm.Dorsal margin straight, situated obliquely to the posterior margin on LV; slighty convexed in the middle of RV.Anterior margin rounded with six small spines on both valves.Posterior margin firstly subvertical then outwards extended.Caudal process distinct.Posterior margin has a three large spines; central two larger.Ventral margin is concave in the middle.There is long, ventral rib continuous with posterior ridge.Anterior angles unstressed, posterior angles distinct, specially posterodorsal one.Carapace surface with 1) caperate rounded fossae and thick muri between posterior and anterior rib and 2) caperate polygonal fossae with thin muri along the posterior and anterior rim.Intramural pore and celate pores with apophysis visible on the valve rim.Anterior rim broad.There is 2 ‡3 subparallel anterior rib.Marginal zone smooth, wider on the anterior part.Eye tubercle visible, large and continuous with anterior rib.
The zone of concrescence broad on both ends.Marginal pore canals long, straight and dense.Muscle scar pattern as the other Hemicytheria.Hinge amphidont.Males lower and longer than females.
P a ra t i po v i. 12 kapaka i nekoliko qu{tura.