Monograptus is a genus of graptolites in the order Graptoloidea. This particular genus is the last stage of the graptoloid evolution before its extinction in the early Devonian. A characteristic of the genus includes one uniserial stipes with very elaborate thecae. This particular genus contains large number of graptolite species and may not be monophyletic.
Biostratigraphic significance[]
The International Commission on Stratigraphy (ICS) has assigned the First Appearance Datum (FAD) of M. uniformis as the defining biological marker for the start of the Lochkovian, 419.2 ± 3.2 million years ago, the earliest stage of the Devonian. ICS has assigned the FAD of M. parultimus defining biological marker for the start of the Pridoli epoch, 423.0 ± 2.3 million years ago, of M. turriculatus (together with the replacement of the brachiopod Eocoelia intermedia with E. curtisi) for the start of the Telychian, 438.5 ± 1.1 million years ago, and of M. austerus sequens for the start of the Aeronian, 440.8 ± 1.2 million years ago, all stages of the Silurian.
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