Maastrichtian non-cephalopod mollusks (Scaphopoda, Gastropoda and Bivalvia) of the Middle Vistula Valley, Central Poland

Abstract

The non-cephalopod mollusks from the Maastrichtian opokas and marls exposed along the Middle Vistula Valley, Central Poland, are represented by 2 scaphopod, 92 gastropod, and 105 bivalve species. Of these mollusks, all systematically studied, 13 gastropod species are new, viz. Loxotoma multiradiata sp. n., Calliomphalus (PlanoIateralus) nasilowensis sp. n., Cerithium mazureki sp. n., Helicaulax pozaryskii sp. n., Cultrigera turriformis sp. n., Columbellaria laevicostata sp, n., Cassidaria truncata sp. n., Biplex cretaceus sp. n., Buccinum giganteum sp. n., Graphidula radwanskii sp. n., Graphidula vistulensis sp. n., Tudicla (Tudicla) globosa sp. n., and Tornatellaea kongieli sp. n. The aporrhaid gastropod genus Kaunhowenia gen. n. is established as new. Amongst the bivalves, only one species is introduced as new: Pinna (Plesiopinna) kasimirensis sp. n. A special attention is given for some species, such as Volutispina kasimiri (KRACH, 1931), Pholadomya (Pholadomya) kasimiri PUSCH, 1837 and Pholadomya (Bucardiomya) esmarki (NILSSON, 1827), the taxonomy of which has often been confused. Discussed is also the occurrence of the two tegulated inoceramids, Spyridoceramus tegulatus (v. HAGENOV, 1842) and Tenuipteria argentea (CONRAD, 1858). The latter species is first recorded in Poland, and it is challenged as an alternative index of the Belemnella kazimiroviensis Zone in the uppermost Maastrichtian. Biogeographic comparisons with the Maastrichtian faunas of other regions show that the studies faunas reflect influences of the North Temperate Realm. Palaeoecologic reconstruction of the studied faunal assemblages (since the Campanian/Maastrichtian boundary through the topmost Maastrichtian) indicates an increase in the density and diversity of the faunal assemblages along with the appearance of new trophie groups, and with the decrease both in depths and in the distance to the shore. The latter factors were obviously controlled by the major regressive phase of the mid- to Upper Cretaceous sea which occupied the Central European Basin.