A Late Ordovician Conodont fauna from the Lower Limestone Member of the Benjamin Limestone in Central Tasmania, and Revision of Tasmanognathus careyi Burrett, 1979

Ten conodont species, including Aphelognathusl sp., Belodina compressa, Chirognathus tricostatus sp. nov., Drepanodus sp., gen. et sp. indet., Panderodus gracilis, Protopanderodusl nogamii, Phragmodus imdatus, Tasmanognathus careyi and T. sp. cf. T. careyi are documented from the Lower Limestone Member of the Benjamin Limestone, Gordon Group, exposed in the Florentine Valley and Everlasting Hills region of central Tasmania. For the first time since its establishment three decades ago, the type species of Tasmanognathus, T careyi, is revised with recognition of a septimembrate apparatus including makellate M, alate Sa, digyrate Sb, bipennate Sc, tertiopedate Sd, carminate Pa, and Pb (angulate Pb1 and pastinate Pb2) elements. Co-occurrence of Phragmodus und at us and Belodina compressa in the fauna indicates a latest Sandbian to earliest Katian (Phragmodus imdatus conodont Zone) age for the Lower Limestone Member of the Benjamin Limestone. All species previously attributed to Tasmanognathus are briefly reviewed, and the distribution of the genus is shown to be more widespread than hitherto recognised (in New South Wales, North China, Tarim Basin, South Korea and northeast Russia), with a probable occurrence in North American Midcontinental faunas.