Paleoecology and Paleobiogeography of the New York Appalachian Basin Eurypterids

Eurypterids are a diverse group of arthropods with a wide range of body morphologies and lifestyles. They are poorly understood because their fossils are rare. However, they are quite prevalent in the Appalachian Basin, typically interpreted to be a hypersaline environment. This paper documents the temporal and geographic distribution of eurypterids in the Appalachian Basin in order to address questions of taphonomy and ecology. It aims to reveal how eurypterid communities evolved through time, as well as how their geographic distribution may have changed. By understanding these patterns, as well as ecological values such as diversity and abundance, we can better understand the role the eurypterids played in the New York and Ontario region of the Appalachian Basin during the Silurian. The Ciurca eurypterid collection housed in the Yale Peabody Museum and collected by Sam Ciurca is the largest and most complete in the world. By using a eurypterid data set to gather information about ecology, such as diversity and abundance, as well as temporal trends, the history of eurypterid assemblages through time can be reconstructed. GIS maps were developed to illustrate and quantify the geographic range, density, and distribution for each time slice as well as for each eurypterid species. A series of eurypterid pulses was detected, when the diversity, overall abundance, and species-level abundance increased markedly. The basin itself was found to be quite homogenous lithologically, a reflection of the outcrop pattern structural overprint of the region. This was also shown by the even distribution of eurypterids for every time slice. The genus Eurypterus was dominant geographically, temporally, and in number throughout the basin. Further map analysis demonstrated a very even distribution of eurypterids throughout the basin. Arguments about taphonomy and the nature of these assemblages are not conclusive. As a whole, this project has resulted in a better understanding of the paleoecology and paleobiogeography of a poorly studied group of arthropods.