The family Costellariidae MACDONALD, 1860 (Gastropoda: Neogastropoda) from the lower Badenian (Middle Miocene) Lajta Limestone Formation of Letkés (Pannonian Basin, Hungary)

Newly collected Middle Miocene Costellariidae gastropod material obtained from the northern margin of the Pannonian Basin (Central Paratethys) is studied. The specimens were found in the lower Badenian (Langhian) limonitic clayey-marly sands of the Lajta Limestone Formation exposed at the Bagoly Hill locality, Letkés (western edge of the Börzsöny Mts, Hungary). Altogether, 17 costellariid species were found, including Bellardithala borzsonyensis spec. nov., Pusia pseudomoravica spec. nov., P. palmulleri spec. nov., and P. crassiornata spec. nov. which are described as new species. Bellardithala boehmi (BOETTGER, 1906), B. lapugyensis (HOERNES & AUINGER, 1880), Ebenomitra pseudopyramidella (BOETTGER, 1906), Pusia avellanella (BOETTGER, 1906), P. paraleucozona (BOETTGER, 1906), and P. vexans (BOETTGER, 1902) are recorded for the first time from the Miocene of Hungary. The taxonomic status of Bellardithala sp. is discussed. As the taxonomic composition of the Costellariidae assemblage found at the locality suggests, a mixture of various shallow- and deeper water species indicates the allochthonous origin of a portion of the association.