Upper Ordovician Streptelasmatid Corals from Scandinavia

The present paper deals with the morphology, ontogeny, and taxonomy of solitary rugose corals belonging to the family Streptelasmatidae from the Upper Ordavieian (Harjuan) sequence of central Sweden and southern Norway. The interna! structures of the corallites ha ve been exaroined by me ans of se ria! peel seetians and special attention paid to the ontogeny of the various species. The variation of the morphological structures within the various genera are discussed and diagrammatically illustrated. Four new genera viz. Helicelasma n.g., Bodophy/lum n.g., Densigrewingkia n.g., and Borelasrna n.g. are proposed. Altogether 17 species are described of which 11 are new. Exantination of the syntypes of Streptelasma comiculum Hall, 1847, the type species of Streptelasma, revealed that this genus is a senior subjective synonym of Brachyelasma. A lectotype of S. comiculum is selected and described.