Like all other arthropods, eurypterids possessed segmented bodies and jointed appendages (limbs) covered in a cuticle composed of proteins and chitin. As in other chelicerates, the body was divided into two tagmata (sections); … 展开

Eurypterids were highly variable in size, depending on factors such as lifestyle, living environment and taxonomic affinity. Sizes around 100 centimeters (3.3 ft) are common in most eurypterid groups. The smallest eurypte… 展开

Until 1882 no eurypterids were known from before the Silurian. Contemporary discoveries since the 1880s have expanded the knowledge of early eurypterids from the Ordovician period. The earliest eurypterids known today, the … 展开

The first known eurypterid specimen was discovered in the Silurian-aged rocks of New York, to this day one of the richest eurypterid fossil locations. Samuel L. Mitchill described the specimen, discovered near Westmoreland… 展开

Historically, a close relationship between eurypterids and xiphosurans (such as the modern Atlantic horseshoe crab) has been assumed by most researchers. Several homologies encourage this view, such as correlating segm… 展开