Biostratigraphic potential of Middle Cambrian hyoliths from the eastern Georgina Basin

Fourteen hyolith taxa are documented from the Middle Cambrian. (Templetonian to Floran) of the eastern (Queensland) portion of the Georgina Basin, Australia, as a contribution toward a prospective Australian Cambrian hyolith biozonation. The described fauna is from the Beetle Creek Formation (including Monastery Creek Phosphorite Member) and Gowers Formation. Additionally, the enigmatic Cupittheca and some indeterminate hyoliths are figured to illustrate aspects of hyolith morphology. Guduguwan hardmani, widespread in Ordian-early Templetonian strata of northern Australia, is here recorded from the early Templetonian of the eastern Georgina Basin. A,new family. Gakidae is established for sulcavitide hyolithomorphs with a conch of pentagonally tabernacular transverse section, to include Gaka, Kalkatungu gen. nov. and possibly Dorsolinevitus. New genera are the hyolithid Yalarrnga mara gen. et sp. nov., sulcavitid Kulangarra kutjurru gen. et sp. nov., gakid Kalkatungu murlu gen. et sp. nov. and angusticornid Yuku tjurtu gen. et sp. nov.; new species are Loculitheca kunka sp. nov., Carinolithes tjikilirri sp. nov., ?Sololites kankari sp. nov., ?Shandongolithes thakal sp. nov., ?Gerkella thuka sp. nov. and ?Yacutolituus rakaiju sp. nov. Taxa in open nomenclature are Foersteotheca cf. dubecensis, ?Holmitheca sp. and ?Dorsojugalus sp. On present knowledge, the potential for an Australian Cambrian hyolith biozonation is limited in the Early Cambrian, but for the Middle Cambrian, G hardmani is a widespread Ordian-early Templetonian indicator, while hyolith distribution in the Monastery Creek Phosphorite Member suggests a faunal turnover at or about the incoming of Acidusus atavus which may provide a basis for biozonation in the Floran stage.