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The evolution and biogeography of three Ordovician orthid brachiopod genera were examined using species-level phylogenetic analyses and phylogenetic biogeography. Species-level evolutionary patterns and taxonomic revisions were documented for Laurentian species of Glyptorthis Foerste, 1914; Plaesiomys Hall and Clarke, 1892, and Hebertella Hall and Clarke, 1892. Recovered evolutionary relationships were used to investigate geological drivers of macroevolutionary and paleobiogeographic patterns in Middle to Late Ordovician brachiopods and constrain the biogeographic origin of the Late Ordovician Richmondian Invasion. Results indicate a transition in the dominant mode of speciation from vicariance to dispersal occurs across the middle Mohawkian M4/M5 sequence boundary. This macroevolutionary shift corresponds to changes in paleoceanographic conditions brought about by diachronous tectonic events related to the Taconian Orogeny and major rise in global sea level. Multiple biogeographic pathways directed the influx of invasive species during the Richmondian Invasion following a relative rise in sea-level and a return to tropical conditions within the Cincinnati Basin. |
