Abstract
The Lower Jurassic (lower Toarcian) Grimmen Formation (formerly known as "Green Series") of Mecklenburg and Western Pomerania (Northeast Germany) yielded two articulated anterior skeletons of fossil fish, which represent a new lepisosteiform genus and species: Mengius acutidens gen. et sp. nov. The new taxon is described. Osteology of the species is most similar to the contemporaneous species of Lepidotes Agassiz. It differs from Lepidotes in having a non-tritoral dentition and a differently shaped operculum. A cladistic analysis shows Mengius acutidens gen. et sp. nov. to be the sister taxon of Lepidotes, accordingly, the new species is assigned to the family Lepidotidae Agassiz. The occurrence of M. acutidens emphasises the endemic character of the lower Toarcian Grimmen Formation fish fauna of Northeast Germany.