Upper Ordovician planktic and benthic graptolites and a possible hydroid from the Tafilalt Biota, southeastern Morocco

Upper Ordovician planktic and benthic graptolites are generally rare in North Africa. Four localities in southern Morocco have yielded graptolitic material from the top of the First Bani Group and the Lower Ktaoua, Upper Tiouririne and Upper Ktaoua formations, the lithostratigraphic units that contain the Tafilalt Biota. Three species of planktic graptolite (in the genera Climacograptus, Diplograptus? and Neodiplograptus), six species of benthic graptolite (in the genera Dendrograptus, Callograptus, Ptilograptus and ‘Dictyonema’) and one probable hydroid (Webbyites? sp.) are described from these sites. Two species are new: ‘Dictyonema’ khadijae sp. nov. and ‘Dictyonema’ villasi sp. nov. Another probable hydroid, a Plumalina-like form from the Lower Ordovician Fezouata Formation, is also illustrated. Some of the Tafilalt graptolites are similar to Bohemian species, indicating faunal links between the regions during the Late Ordovician. The graptolite dating of some isolated localities helps to evaluate the chronostratigraphic and lithostratigraphic assignment of those outcrops, implying an earlier appearance of the ‘Dendrocystites fauna’ (echinoderm-dominated: c. Sandbian 2–Katian 1) and a late placement for the ‘Declivolithus fauna’ (trilobite-dominated: c. Katian 2).