The paleoecology of Prasopora falesi, a Late Ordovician trepostome bryozoan, has not been thoroughly investigated. In this study specimens of Prasopora falesi were collected from the Decorah Formation (Sandbian) at two sites: Shop Quarry in southeastern Minnesota, and Decorah-Bruening Quarry in northeastern Iowa. Prasopora falesi were discoidal to hemispherical trepostome colonies that lived throughout the Ordovician. This study focuses on the Prasopora falesi found in the Decorah Formation within the Carimona member of the Upper Ordovician. The species was determined through the presence of acanthopores, spike like features that protected the colony. Prasopora falesi were free-living (unattached) filter feeders with autozooids. Maculae, also known as excurrent zones, are areas of the colony where the flow of water is filtered through and released. The advantage of this is an increase in efficiency of flow and a decrease in pressure and amount of water and particles being re-filtered to the autozooids. The paleoenvironment that Prasopora falesi lived in was shallow marine, below the normal wave base but above the storm wave base. There were brachiopods, crinoids, bivalves, trace fossils, rugose corals, other bryozoans, nautiloids, trilobites, conodonts, and gastropods within the environment.


Wilson, Mark




Paleontology | Sedimentology | Stratigraphy


Prasopora falesi

Publication Date


Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis



© Copyright 2017 Rachel M. Wetzel