Arenigian and Llanvirnian cocodonts from Jämtland, northern Sweden

Ordovician sections from seven localities have been measured, described and sampled. Three members of the Flåsjo Formation are proposed. The conodonts represent biozones ranging from earliest Arenigian to middle panvirnian. Four new subzones are distinguished, and the Eoplacognathus suecicus Subzone of the Pygodus serra Zone is extended down into the latest Kundan, and called the Eoplacognathus suecicus Zone. The conodont faunas are compared with those of equivalent age in other areas. The absolute and relative abundance of the conodonts and their colour are briefly diseussed. 53 formally named speeies, five subspecies and 23 taxa described under open nomenclature are treated. Five new species, Belodella jemtlandiea, Paltodus? jemtlandicus, Protopanderodus paroibasis, Scalpellodus viruensis, and Scolopodus bulbosus and one new subspecies, Prioniodus (Baltoniodus) prevariabilis norrlandicus and also other, previously incompletely known species are described in detail. Surface microstructure is described, and apparatuses are reconstructed. Critical synonymy lists and regional occurrence of the species are included.