Rare colonial corals from the Upper Ordovician Kope Formation of Kentucky and their role in ephemeral invasions in the Edenian
Abstract A large colonial rugose coral was recently discovered as float partially buried beneath several inches of sediment in the Kope Formation of northern Kentucky. Corals are unreported in the Kope assemblage, not appearing until much later during the C4 and C5 sequences during the Richmondian Invasion, a period in which the area was inundated with invasive taxa migrating from the midcontinent. The slab contains the remains of several other species that are diagnostic of the Kope Formation, such as the brachiopods Sowerbyella rugosa and Zygospira cincinnatiensis. The large colonial rugose coral is composed of corallites ranging in diameter from 3 to 5 mm containing 10–14 twisting major septa with crenulated walls, which is consistent with Cyathophylloides cf. C. burksae. New taxa or new occurrences in a well-sampled formation, such as the Kope Formation, are unexpected especially for large skeletonized taxa, and highlights the rarity of coral within the assemblage. The Richmondian Invasion is linked to a transgressive event that increased connectivity between marine biogeographic provinces, disrupted ecosystem structure as well as acted as a significant evolutionary driver during the late Ordovician in the Cincinnatian faunal assemblages. Isolated dispersal events may have brought planktonic larva onto the Cincinnati Arch much earlier during transgression in the C1 sequence. The failure of the coral to become established might be linked to the low abundance of larva entering the region or non-ideal environmental conditions. The discovery of this coral in the Kope Formation further indicates the occurrence of rare and ephemeral dispersal events that have recently been reported within brachiopods.