Isolated marginal teeth and tooth crowns of Late Campanian and Late Maastrichtian mosasaurid reptiles (Squamata, Platynota) from the Wisła River valley area, central Poland, are described and illustrated. These comprise two Late Campanian taxa from Piotrawin quarry: Prognathodon sp. and Plioplatecarpinae sp. A., and four late Late Maastrichtian taxa from Nasiłów quarry: Mosasaurus cf. hoffmanni Mantell, 1829, M. cf. lemonnieri Dollo, 1889c, "Mosasaurus (Leiodon) cfr. anceps" sensu Arambourg (1952), and Plioplatecarpinae sp. B. In addition, the previously described fragmentary jaw with associated teeth of the Late Campanian age from Maruszów quarry (west of the Wisła River area), is reassigned to Mosasaurus cf. hoffmanni. This specimen suggests that M. hoffmanni or a closely related (ancestral?) species already appeared in Europe during the Late Campanian (well-documented European occurrences of M. hoffmanni are Late Maastrichtian in age). At least part of the described mosasaur material is likely to stem from periodic feeding in the area (broken-off or shed tooth crowns) or from floating carcasses (complete teeth and jaw fragments).

Key words: Reptilia, Squamata, Platynota, Mosasauridae, Upper Cretaceous, Campanian, Maastrichtian, Poland.

Marcin Machalski [mach@twarda.pan.pl], Instytut Paleobiologii PAN, ul. Twarda 51/55, PL 00−818 Warszawa, Poland; John W.M. Jagt [john.jagt@nhmmaastricht.nl], Natuurhistorisch Museum Maastricht, de Bosquetplein 6−7, P.O. Box 882, NL−6200 AW Maastricht, the Netherlands; Rudi W. Dortangs, Hoofdstraat 36, NL−6436 CG Amstenrade, the Netherlands; Eric W.A. Mulder [eric292@gmx.net], MuseumNaturaDocet, Oldenzaalsestraat 39, NL−7591GL Denekamp, the Netherlands; Andrzej Radwański, Instytut Geologii Podstawowej, Wydział Geologii UW, Al. Żwirki i Wigury 93, PL 02−089 Warszawa, Poland.