The study of Ordovician ostracods from eastern North America has been neglected for more than 40 years, prompting the need for taxonomic updates. Newly acquired silicified materials from the Late Ordovician Crown Point Formation of Valcour Island, northeastern New York State, are here systematically described. Fifty-two species of 42 genera are identified, including three new species: Vogdesella longidorsa n. sp., Eokloedenella duodepressa n. sp. and Aviacypris valcourensis n. sp. The combination of high diversity and dominance of both beyrichiocopids and podocopids indicates that the Valcour fauna existed in a stable, shallow-water carbonate environment. Biostratigraphical evidence supports an early Sandbian age designation for the Crown Point Formation. Comparison of the Valcour fauna with others in Laurentia as well as from adjacent paleocontinents shows shared composition at the genus level, especially with Baltica, but high endemicity at the species level. This suggests a history of frequent faunal exchange with a fast speciation rate during the early Late Ordovician in the southern region of Laurentia.

UUID: http://zoobank.org/e12dc8ce-0b2a-4f9d-aca2-bf3e298d9635