DIVERSITY AND PALEOECOLOGY OF A NEW ORDOVICIAN (KATIAN) CRINOID FAUNA FROM THE NEUVILLE FORMATION, SOUTHERN QUÉBEC, CANADA

The Neuville Formation preserves a diverse echinoderm paleocommunity, including a moderate diversity crinoid fauna. Disparids and cladids dominate the fauna comprised of at least two diplobathrid camerates, five disparids, and four cladids. Crinoids were preserved in multiple obrusion deposits that resulted in exquisite preservation. Complete specimens (arms to holdfasts), including juveniles and adults, are known for most species, and numerous biotic interactions among crinoids are also preserved. The Neuville fauna is a unique Katian crinoid assemblage compared to other contemporary faunas, such as those in the Cincinnati Basin and southeast Ontario. It lacks monobathrid camerates, hybocrinids, and flexible crinoids, all of which are typically abundant in Katian crinoid faunas. The Neuville paleocommunity shares several genera and species with the Katian of the Cincinnati region, but it also contains genera not present in the Cincinnati region as well as new species. Among disparids, Neuville specimens exhibit a gradient of morphological features intermediate between Ectenocrinus and Drymocrinus, possibly representing hybrids or a species complex, and require further evaluation.