SHARKS FROM THE MIDDLE-LATE DEVONIAN AZTEC SILSTONE, SOUTHERN VICTORIA LAND, ANTARCTICA

WA Museum Records and Supplements | Updated 1 decade ago

Abstract - Shark teeth representing three new taxa are described from the Middle-Late Devonian Aztec Siltstone of southern Victoria Land, Antarctica. Portalodus bradshawae gen. et sp. novo is represented by large diplodont teeth which have a base with a well-produced labial platform. It occurs in the middle to upper sections of the Aztec Siltstone. Aztecodus harmsenae gen. et sp. novo is represented by broad bicuspid teeth, wider than high, with numerous medial crenulations and twin nutritive foramina penetrating the rectangular base. It occurs in the middle sections of the Aztec Siltstone. The teeth of Anareodus statei gen. et sp. novo are characterised by having a main cusp which is more than twice as high as the second cusp, a small cusplet developed on the outer cutting edge of the main cusp, sometimes with few crenulations developed in the middle of the two cusps, and the base is strongly concave. Antarctilanma cf. prisca Young, 1982 is also recorded from the middle and upper sections of the Aztec Siltstone above the thelodont horizons and occurring with phyllolepids and Pambulaspis in the Cook Mountains section south of Mt Hughes. The chondrichthyan fauna from the Aztec Siltstone now contains at least 5 species, being the most diverse assemblage of Middle Devonian chondrichthyans (based on teeth) from one stratigraphic unit.