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Definition of EURYPTERID
: any of an order (Eurypterida) of usually large aquatic Paleozoic arthropods resembling scorpions and related to the horseshoe crabs —called also sea scorpion
Illustration of EURYPTERID
Origin of EURYPTERID
ultimately from Greek eury- + pteron wing — more at feather
First Known Use: 1871
Member of an extinct order (Eurypterida) of arthropods, similar in body plan to the horseshoe crab, that lived c. 505–245 million years ago. Frequently referred to as giant scorpions, most eurypterids were small, although Pterygotus buffaloenis, a species from the Silurian period, was the largest arthropod ever known, reaching a length of about 10 ft (3 m). The eurypterids lived in brackish waters. Some were predators; others were probably bottom-dwelling scavengers.