• Aquatic or semiaquatic vertebrates are common in both the Pinpa and Ericmas LFs in the Namba Formation, including fish, turtles, crocodilians, and dolphins (Tedford et al. 1977; Fordyce 1983; Rich et al. 1991), revealing the presence of a permanent lake in the basin during this time period. The dolomitic layers at the site suggest periods of time when sections of the lake would seasonally dry out (Callen 1977). The afore-mentioned pollen record from the Namba Formation reveals that the depositional environment was dominated by a mix of rainforest and temperate forest surrounding sedge-lined lakes in the late Oligocene to early Miocene when the Pinpa LF was present (Martin 1990). The range in habitats resulted in a diverse vertebrate fauna inhabiting this area in the late Oligocene, resulting in a fossil fauna that is a key snapshot into our understanding of the evolution of Australian animals.

• The Pinpa LF derives from beds of olive and orange mottled clay and white dolomitic mudstone stained with manganese at the top of the lower member of the Namba Formation, which crops out at Lake Pinpa and Billeroo Creek (Tedford et al. 1977; Rich et al. 1991; Thorn et al. 2021).