Perisphinctes orbignyi n. sp. and accompanying perisphinctid assemblage from the Lower Oxfordian (Cordatum Zone, Cordatum Subzone) in southern Poland (Zalas, Krakow region)

The paper presents preliminary characteristics of a new perisphinctid assemblage from the Lower Oxfordian section of Zalas near Krakow, regarded as the classic one for southern Poland. The assemblage is derived from strata of the Cordatum Subzone, Cordatum Zone. Two major groups of perisphinctids are differentiated. The assemblage appears similar to those described by Neumann from Cetechowitz 〚12〛, Bourseau from ‘Terres noires’ of de Beauvoisin in France 〚2〛, and Gygi from Switzerland 〚9〛. It fills very well a gap in our knowledge of this fauna from upper parts of the Lower Oxfordian and further studies should make it possible to propose and define a new biostratigraphic unit. A new ammonite species Perisphinctes (Arisphinctes?) orbignyi n. sp. is described. Its name is given to commemorate the bicentenary of the birth of Alcide d’Orbigny and his contribution to the developments of stratigraphy of the Mesozoic, especially Jurassic strata.