A new silicified plectorthoid brachiopod from the upper Furongian (Stage 10) Ninmaroo Formation at Black Mountain, western Queensland, Australia

The Ninmaroo Formation is a thick succession of richly fossiliferous carbonates that straddles the Cambrian (Furongian, Stage 10)–Lower Ordovician (Tremadocian, Tr1) boundary in the vicinity of Black Mountain (Mount Unbunmaroo) in western Queensland. Abundant, relatively coarsely silicified specimens of a plectorthoid brachiopod recovered from the lower Corrie Member of the Ninmaroo Formation type section are taxonomically described as a new species, Apheoorthis talenti n. sp. The stratigraphic level hosting the brachiopods occurs above the first occurrence, but within the biostratigraphic range, of the important age-diagnostic conodont species Cordylodus lindstromi which represents the upper Furongian Series (Stage 10) globally. In the Australian context, the new brachiopod occurs in the basal Warendan regional stage. Brachiopods are rare in Furongian rocks from Australia, making A. talenti n. sp. one of very few Cambrian Stage 10 rhynchonelliform brachiopods described from Australia.