Transactions of the Royal Society of Edinburgh: Earth Sciences

Research Article

Summary of a revision of New York State Ordovician eurypterids: implications for eurypterid palaeoecology, diversity and evolution

Victor P. Tollerton Jra1

a1 1908 Sunset Avenue, Utica, New York 13502–5618, USA e-mail:


The record of Ordovician Eurypterida from New York State, USA, is shown to be largely false. Twenty-nine species in 17 genera are here recognised as pseudofossils, reducing by more than 75% the total number of named Ordovician eurypterid taxa. Consequently, 10 families now have their first occurrence either later in the Ordovician or in the Early Silurian. The implications for eurypterid palaeoecology, diversity and evolution are not as straightforward as would be expected from such a drastic taxonomic revision. All Ordovician eurypterids are now known to occur in shallow-water, near-shore shales or fine-grained carbonates. Diversity measures indicate that the end-Ordovician extinction event appears to have had less effect on eurypterids than previously known, and their turnover is level in the Ordovician.

(Received July 21 2003)

(Accepted March 29 2004)


  • Arthropoda;
  • Chelicerata;
  • distribution;
  • Early Silurian