Conodont and crinoid stratigraphy of the upper Silurian and Lower Devonian scyphocrinoid beds of Tafilalt, southeastern Morocco

Three sections (Atrous 3, Atrous 7 and Bou Tchrafine N2) in the “Scyphocrinites Limestones” of Tafilalt (southeastern Morocco) have been investigated for conodont and crinoid stratigraphy. Conodonts allow to discriminate four biozones (Ozarkodina eosteinhornensis s.l., Lower Oulodus elegans detortus, Upper O. elegans detortus, and Icriodus hesperius) of Pridoli and the lowermost Lochkovian. Cirrus loboliths occur only in the Pridoli, whereas plate loboliths are present in the uppermost Silurian and the basal Devonian; the two types overlap in the uppermost Silurian. As for calices, Scyphocrinites and Carolicrinus occur in the whole Pridoli; Camarocrinus and Marhoumacrinus are present across the Silurian–Devonian boundary and in basal Devonian beds.