A new species of Nothosaurus from the Lower Keuper (Lettenkeuper, Ladinian, Erfurt Formation) of Vellberg-Eschenau, southern Germany, is described on the basis of a nearly complete skull that is only missing the lower jaw. Together with Nothosaurus edingerae, it is the only valid Nothosaurus species exclusively known from the Lower Keuper (Ladinian) of the Germanic Basin. Nothosaurus cristatus, sp. nov., differs from all other nothosaurs by exhibiting a postorbital that is excluded from the orbital margin by the postfrontal, the maxilla, and the jugal. The postfrontal and the maxilla form the posterior orbital margin exclusively. The parietal forms a pronounced and sharp crest anterior to the parietal foramen, which is unique among Nothosaurus. The ectopterygoid bears a long posterior process. A phylogenetic analysis of Nothosaurus cristatus, based on Liu et al. (2014, Scientific Reports 4:7142, doi: 10.1038/srep07142) with modified characters after Lin et al. (2017, Journal of Vertebrate Paleontology, doi: 10.1080/02724634.2017.1278703), yielded a nearly unchanged topology that supported the monophyly of (N. jagisteus (N. cristatus (N. mirabilis + N. tchernovi))).