PALEO-ECOLOGICAL COMPARISON BETWEEN THREE E.E. SUB UNITS IN THE MIDDLE DEVONIAN OF EASTERN NORTH AMERICA

The hypothesis of Coordinated Stasis proposes that various intervals in the rock record contain long-lasting faunal associations with little to no change in their composition. To date, investigations of Coordinated Stasis have been conducted primarily on taxonomic composition. This study purposes examine the stability of ecological niche partitioning across three Ecological Evolutionary sub-Units in the Middle Devonian of eastern North America: the Onondaga, Stony Hollow, and Hamilton faunas.

The fauna of the Stony Hollow interval, though fairly well understood, still remains some what of an enigma as it is preserved in a very thin interval in most areas. Taxa of the Stony Hollow Fauna are known to have immigrated into the area from what were at the time more equatorial areas in northern Canada, displacing the existing suite of taxa for nearly one million years. This fauna is thought to have followed a major sea level rise and influx of warmer water down into the basin that was extant across the state at this time.

Although the basic nature of the Stony Hollow Fauna is known as described above, a precise description of the ecological nature of the fauna has yet to be completed. The proposed project will consists of collection of samples throughout the Stony Hollow interval across eastern North America and a thorough description of the paleoecology of all taxa present. To date only the brachiopod taxa of the Stony Hollow Fauna have been examined in any great detail while other abundant forms, such as bivalved mollusks and corals, remain almost completely unknown. With a more complete understanding of the unique fauna of this interval it will be possible to make broader comparisons of faunal change across wide areas of the globe and elucidate the precise mechanisms driving large-scale faunal change.