Two multiramous graptoloids from the Lower Didymograptus Shale of Scandinavia

A pyritized specimen of Goniograptus sp. is described from the Lower Didymograptus Shale of Jämtland, northern Sweden. This is the first record of an undoubted Goniograptus from northern Europe. The probable mode of branching of the stipes is described from observations on an internal mould preserved in full relief. The morphology and taxonomy of the Lower Ordovician graptoloids with prothecal folds is treated in some detail. This group, which possibly can be traced back into Upper Tremadocian strata, is included in the family Sinograptidae Mu, 1957. Evidence is summarized which indicates that the sinograptids are the probable ancestors of the Dicranograptidae and that the Leptograptidae are probably derived independently from some extensiform didymograptids of the family Dichograptidae. The new generic name Cymatograptus (type species: Didymograptus undulatus Törnquist) is proposed for bira‐mous sinograptids with simple thecae of the dichograptid type. A new quadriramous sinograptid genus Oslograptus n. gen. and its type species Oslograptus peculiaris n. sp. are described from the Lower Didymograptus Shale of the Oslo area, Norway