Tyrrhenocythere Ruggieri ve ona ait pekçok tür, Paratetis’e ait havzalarda Ponsiyen bafl›ndan zaman›m›za de¤in oldukça bol miktarda gözlenmektedir. Cinsin temel karakteristik niteli¤i, kenar delik kanallar›n›n gruplar halinde bulunmas›d›r. Bu çal›flmada, Arakl› kesitindeki sedimanter istif içerisinde Orta Geç Ponsiyen yafl›n› karakterize eden oniki ayr› Tyrrhenocythere türü ay›rtlanm›fl ve tan›mlanm›flt›r. Sekiz tanesi yeni olan bu türler; Tyrrhenocythere arakliensis, Tyrrhenocythere turcica, Tyrrhenocythere alatum, Tyrrhenocythere alatum reticulata, Tyrrhenocythere trabzonensis, Tyrrhenocythere batmani, Tyrrhenocythere goekcenae ve Tyrrhenocythere agalarovae’d›r. Bilinen ve isimlendirilmemifl türleri içeren di¤er dördü ise; Tyrrhenocythere pontica, Tyrrhenocythere filipescui, Tyrrhenocythere sp.1 ve Tyrrhenocythere sp. 2’ dir.

Tyrrhenocythere Ruggieri and many of its species were observed in abundant amounts in the basins of Paratethys from the beginning of the Pontian to Recent. The main characteristic of the genus is its marginal pore canals groupped in bundles. In this study, twelve species, which characterize the Middle-Late Pontian, were identified and determined in the sedimentary sequence of the Arakl› Section. The eight of them are Tyrrhenocythere arakliensis, Tyrrhenocythere turcica, Tyrrhenocythere alatum, Tyrrhenocythere alatum reticulata, Tyrrhenocythere trabzonensis, Tyrrhenocythere batmani, Tyrrhenocythere goekcenae and Tyrrhenocythere agalarovae. The other known and unnamed Tyrrhenocythere species are Tyrrhenocythere pontica, Tyrrhenocythere filipescui, Tyrrhenocythere sp. 1 and Tyrrhenocythere sp. 2.