A new species of the sauropterygian genusNothosaurusfrom the Lower Muschelkalk of Winterswijk, The Netherlands

Abstract

A new species of the genusNothosaurusfrom the Lower Muschelkalk of Winterswijk, The Netherlands, shows relatively plesiomorphic features such as a relatively forward position of the pineal foramen. The jugal enters into the ventral margin of the orbit, which would also be regarded as plesiomorphic, were it not that this feature optimizes unequivocally as a reversal and, hence, as a diagnostic (derived) character of the new taxon. The new taxon does not, however, increase the fit of the cladogram for the phylogenetic relationships withinNothosaurusto the stratigraphic record of the genus. The basal position ofNothosaurus juvenilisremains problematic.