Early Ordovician acritarchs from southern Jilin Province, north-east China

Preliminary sampling of early Ordovician deposits in the Hunjiang region, southern Jilin Province north-east China, yielded generally well-preserved acritarchs, the seven most characteristic species of which are described. The strata form part of the northern margin of the Sino-Korean platform and are dated by graptolite ranging from Tremadoc (= post Rhabdinopora parabola Biozone and excluding early Tremadoc) to lates Tremadoc or earliest Arenig (Adelograptus-Clonograptus, with Kiaerograptus, fauna). The appearance of Rhopaliophora Tappan and Loeblich, 1971 emend. Playford and Martin, 1984 is considered with reservation as marking the base of the latter interval. New taxa comprise two genera, Aryballomorpha and Lua, and two nev species, L. erdaopuziana (type species) and Athabascaella penika. Other species of Athabascaella, A. playfordi Martin, 1984 (type species), A. rossii Martin, 1984, and Aryballomorpha grootaertii (Martin, 1984) comb. nov (type species) are emended; all three taxa are known from the Tremadoc of Laurentia, in strata of the southen Canadian Rocky Mountains dated by trilobites as belonging to letter zones D and E of Utah and Nevada, USA