Late Triassic small and medium-sized vertebrates from the Fleming Fjord Group of the Jameson Land Basin, central East Greenland

Abstract

The Late Triassic deposits in the Jameson Land Basin, central East Greenland, stand as a crucial fossil area, yielding a diverse Norian vertebrate fauna. This basin, situated at a palaeolatitude of 41° N on the northern rim of Pangea and bordered in the North by the Boreal Sea, was a hub of activity during the Late Triassic. A large ephemeral to perennial lake system developed in the central and eastern parts of the basin, with rivers transporting sediment from the uplands northwest of the basin. Our research focused on the microvertebrate remains recovered from an expedition to Jameson Land in 1991 which yielded significant findings. These specimens, meticulously photographed and listed in a catalogue, comprise 950 vertebrate remains. Notably, we have identified new taxa never described from the Late Triassic sediments of Greenland, including sharks (Lissodus, Rhomphaiodon), bony fish (Gyrolepis), and reptiles (Doswelliidae and Rhynchocephalia). The revision of two sphenodontians jaw fragments as Clevosauridae, in association with Lissodus lepagei, Lissodus cf. Lissodus minimus, Rhomphaiodon sp., Saurichthys sp., and Gyrolepis sp., which are taxa that are highly documented in Europe and Asia, confirms a relationship between faunas of Greenland and Eurasia during the Late Triassic, a statement previously based on macro vertebrate studies.