Shallow-water predators (“sea scorpions”), up to 7 feet long, that diversified during the Silurian.
Arthropods, probably related to spiders and scorpions.
Most species were eight inches long or less.
Started in the sea, but moved into brackish and eventually fresh water.
External morphology probably the best known of any group of fossil animals.
◄ Eurypterus remipes,
about seven inches long,
Fiddler’s Green Formation,
Herkimer County, New York.
Image courtesy of The Virtual Fossil Museum, www.fossilmuseum.net.