Fossil chondrichthyan remains from the Middle Devonian Kevington Creek Formation, South Blue Range, Victoria

Chondrichthyan teeth are described from a new site located in the upper section of the Middle Devonian Kevington Creek Formation, NW Victoria. Our review of the genus Mcmurdodus White, 1968 indicates that the Australian teeth previously assigned to this genus, which have up to eight large asymmetric cusps, belong in a separate genus from the type species, which has a central row of median cusps separating three larger lateral cusps. We refer the Australian species M. whitei Turner & Young, 1987 to Maiseyodus new genus, and describe a new occurrence of this species from the South Blue Range assemblage. The co-occurrence supports an Eifelian age for the South Blue Range unit, as M. whitei is otherwise known only from the late Early/early Middle Devonian Cravens Peak Beds of western Queensland (Emsian-Eifelian boundary). The younger occurrence of the type of the genus Mcmurdodus in the Aztec Siltstone of Antarctica (Eifelian-Givetian) and the presence of Aztecodus sp. cf. A. harmsenae and Antarctilamna prisca in the Kevington Creek Formation fauna would also support an older age than previously estimated for the South Blue Range Devonian succession. Revised U-Pb dates on the nearby Toombullup Ignimbrites supports an older age for the fish-bearing sequence at the base of the Mansfield Basin sequence. Biostratigraphic correlation of key chondrichthyan species found in the Aztec Siltstone of Antarctica and the Cravens Peak Beds limestone member suggests that the South Blue Range succession is much older than previously placed. It is likely a correlate of the lower part of the Aztec Siltstone succession