Taxonomy and distribution of the genus Tavanicythere Bossio, 1980 (Ostracoda, Leptocytheridae)

The genus Tavanicythere was established in 1980 by Bossio on the basis of several valves recovered in the Lower Messinian brackish deposits of the Radicondoli area (Volterra Basin, Tuscany, central Italy). Three species were included in this genus: Tavanicythere lepida Bossio (the type species), Tavanicythere etrusca Bossio and Tavanicythere pulchra Bossio. Since then, many other specimens referable to Tavanicythere have been collected from several Neogene Tuscany basins (Volterra, Valdelsa, Cinigiano-Baccinello), but no specific identifications were carried out and they were generally reported in literature as Tavanicythere sp. In this paper we have revised all the collected material. Up to 15 different new taxa have been recognised, even if only 11 are formally established herein as new species, due, in some cases, to the scarcity of valves: Tavanicythere varieornata nov. sp., Tavanicythere persculpta nov. sp., Tavanicythere posteroalata nov. sp. Tavanicythere sulcata nov. sp., Tavanicythere magna nov. sp., Tavanicythere nodosa nov. sp., Tavanicythere armata nov. sp., Tavanicythere ioachinoi nov. sp., Tavanicythere julianii nov. sp., Tavanicythere parva nov. sp. and Tavanicythere irregularis nov. sp. Only few species of Tavanicythere appear to be distributed in different basins, the majority being confined to one basin only. This could be due to particular brackish environmental conditions that triggered basin endemisms. The recovery of new Tavanicythere species lead to enlarge the stratigraphical distribution of this genus, prior limited to the Early Messinian, to the time interval Late Tortonian-Messinian. Tavanicythere seems to be widespread only in the Mediterranean basin and, in particular, in Italy (Tuscany). At present, outside of Italy it has been collected only from the Late Messinian brackish deposits of the Sorbas basin (SE Spain).