Upper Jurassic and Neocomian ostracodes from Central Poland

Abstract

The ostracode. contained within the Upper Kimmeridgian and Lower to Middle Volgian deposits piereed by eleven bareholes in the Barcio-Piechcin .area (Kujawy region) and exposed at Brzostówka in Tomaszów Mazowiecki (NW margins of the Holy Cross Mts), as well as those collected from the Neocomian deposits exposed at Wąwał near Tomaszów Mazowiecki and pierced by boreholes at the nearby localities allow to distinguish four ostracode zones in the Upper Kimmeridgian-Volgian sequence: G. monstrata, G. oertlii, G. barcinensis and G. punctilataeformis Zones, and two others, P. aubersonensis and M. frankei Zones, within the Neocomian deposits. The newly recognized ostracode zones are correlated with the ammonite subdivisions of the Upper Kimmeridgian, Lower and Middle Volgian, and the Neocomian. In the paleontological part of the paper described are 37 species (4 new) of the Upper Jurassic ostracodes, and 51 species (18 new) of the Neocomian ostracodes. Some of the recognized species display a pronounced ornamental variability which, among the Neocomian ostracodes, is ascribed to the ecophenotypic differentiation caused by the environmental stimuli.