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Monograptus (class Graptolithina) The first recorded monograptid genus, from the Early Llandoverian (Lower Silurian). Successive evolutionary trends within the graptolites resulted in the development of the single-branched monograptids. These had only a limited number of thecal cups (see THECA) on one side of the branch although the cups were large and exhibited considerable morphological variation. Compare DENDROIDEA; and GRAPTOLOIDEA.