SUBLETHAL AND LETHAL INJURIES IN EURYPTERIDS FROM THE BERTIE GROUP (SILURIAN) OF NEW YORK

Eurypterid exoskeletons from the Bertie Group (Upper Silurian), both the Fiddler’s Green Formation of central New York, and the Williamsville Formation of western New York, were studied for evidence of malformation. Healed, sublethal injuries have been identified in four specimens of Eurypterus remipes, one specimen of E. lacustris, and in a telson of Acutiramus macrophthalmus. Healed, sublethal injuries are indicated by scarring, which usually includes a distinct, dark, somewhat thickened line surrounding the injury. Most of the observed injuries are marginal, roughly V-shaped, and can be attributed to sublethal predation. They are on locations of the body where vital organs were not present. Cephalopods, which are relatively common in the Bertie Group, may have been responsible for some of the V-shaped injuries. Arthropods, including possibly eurypterids, also may have inflicted some injuries. One specimen of E. remipes exhibits a series of small, healed pits, suggesting sublethal puncture of the abdomen by the chelicera of a pterygotid eurypterid.

Most eurypterids from the Bertie Group are represented by exoskeletons in various stages of incompleteness. Separated sclerites and broken sclerites are common, and the vast majority show no evidence of scarring. Although the origin of breakage could have varied biological and physical causes, including desiccation-related cracking and wave agitation, many of the broken, unhealed sclerites are likely the result of successful predation or scavenging.