How diverse is the temnospondyl fauna in the Lower Triassic of southern Germany?

Abstract

Among the few fossiliferous Lower Triassic deposits in Europe, the Lower to Middle Buntsandstein of the German southwest has yielded a range of interesting finds. A review of the pub- lished and new material gives the following results: (1) The oldest identified remain is a mandible of a small stereospondyl from the Bernburg Formation (Induan); (2) A new palate from the early Olene- kian (Badischer Bausandstein) stems from a basal capitosaur similar to Wetlugasaurus; (3) In the late Olenekian (Hardegsen Formation), two well-defined temnospondyl genera are present: the basal capitosauroids Meyerosuchus fuerstenbergianus and Odenwaldia heidelbergensis. Large remains formerly referred to Mastodonsaurus either pertain to a different family or are undiagnostic, pushing the first occurrence of mastodonsaurids into the Anisian. These finds highlight the presence of large aquatic predators by early Triassic time, revealing an increasing diversity of aquatic predators from the Induan to the Anisian. The documented faunal changes involved patterns of immigration and extinction/emigration rather than endemic evolution within the basin. In contrast to the northern parts of the basin, the genera Trematosaurus, Parotosuchus, and Sclerothorax are absent in the southern part, where Meyerosuchus and Odenwaldia existed.