Middle-Upper Ordovician conodonts from the Ffairfach and Golden Grove groups in South Wales, United Kingdom

The conodont fauna of the reference succession regional British Llandeilian Stage Llanvirn Series was first described in a classical study by Rhodes more than 65 years ago using single element (form) taxonomy. Although several subsequent authors have recorded substantial number taxa from Llandeilo area, present is to modern taxonomic review these late Darriwilian-early Sandbian faunas that include approximately 20 multielement species. Most prominent are representatives Amorphognathus, Baltoniodus, Eoplacognathus, and Plectodina. their own biogeographical character. distinctive genera Complexodus, Protopanderodus, Pygodus, which common coeval Baltoscandic faunas, not present, but occurrence Eoplacognathus provides link age equivalent faunas. presence abundant specimens Plectodina less Erismodus Icriodella reminiscent North American Midcontinent This type faunal assemblage some respects similar those early Caradoc Welsh Borderland. Biostratigraphically diagnostic species indicate ranges lindstroemi Subzone Pygodus serra Zone Baltoniodus variabilis Amorphognathus tvaerensis Zone.