New calcareous nannofossils from the Middle to Late Miocene of the North Croatian Basin, Central Paratethys

Calcareous nannofossils include all remains of marine haptophyte algae, which are usually smaller than 30μm (Bown and Young, 1998). Because of their planktonic mode of life, these unicellular algae are widespread in the photic zone of all oceans and are very useful for biostratigraphy and paleoecology. The systematics of calcareous nannofossils are based on the structure, shape and size of the coccoliths, which is implemented in descriptions of new species. Middle/Late Miocene sediments in the southern part of the Central Paratethys were investigated from four localities: Slapno, Kostajnica, Bukova Glava, Vranović and Beočin. The investigated Middle Miocene sections Bukova Glava (45.4486°N, 18.0322°E) and Kostajnica (45.2283°N, 16.5590°E) are situated in North Croatian Basin, SW Paratethys. The light marl from the quarry of the cement factory Beočin (Vojvodina, Serbia ; (45.1972°N, 19.7350°E) was sampled in 1885, and kept in the collection of the Natural History Museum Vienna. The outcropping marly sediments are attributed to the Badenian PNN6 to Pannonian PNN9 of the Paratethys (Galović, 2020, 2021), which can be generally correlated with the Serravallian Zone NN6-NN7 (Martini, 1971) to Tortonian Zone NN8 of Martini (1971). The Sarmatian marls concordantly lay on the Badenian marls at Bukova Glava and Kostajnica and continue concordantly to the Pannonian at Vranović (Galović, 2020 ; Grizelj et al., 2020). Marls are horizontally laminated or massive with bioturbations in some parts. Some intercalations of limestones, sands, siltstones and organic-rich layers occur in the marls. A new genus (Jeremyella), and species (Jeremyella levkovii, Cruciplacolithus pavsicii, Reticulofenestra galovicorum, R. benicii, Prenoelaerhabdus galoviciae, Coronosphaera caputiae) of Heterococcoliths, two new genus (Nivisolithus and Planolithus) and several new species of nannoliths (Nivisolithus kovacicii, Nivisolithus vrabacii, Planolithus mihajlovicii, Planolithus eggeri, Isolithus pavelicii, Isolithus kovacii, Micrantholithus cosoviciae) are proposed from the middle to late Miocene of the Central Paratethys.