In the Earth's prehistoric past, strange creatures swam through the ocean with shells, claws, and creeping legs. These long-extinct arthropods are known as Eurypterids, though they are better recognized by their nickname: the Sea Scorpions.

Eurypterids were not literally scorpions, though they do have a distant relation to the modern bugs. Looking at their body shape, however, it is easy to see the similarities. These ocean predators had long bodies and crawling limbs, and many species had forward-facing appendages with long spines or even claws. These grippers were used to capture prey and made quite a fearsome profile.

This specimen is a sea scorpion fossil from the species Eurypterus remipe. It was collected on private land in Lang's Quarry, part of the Upper Silurian Fiddler's Green Formation in New York. The fossil is estimated to be around 420,000,000 years old and shows the body plan of a sea scorpion in fine detail.

Each showcase fossil is photographed individually and listed by size. This specimen ships in a padded carton along with a black metal stand. A certificate of authenticity is also included. You can see all currently available sea scorpion fossils in the collection below!

Eurypterids, better known as sea scorpions, were some of the largest arthropods ever to live on planet Earth, a highly diverse group of over 250 species with a worldwide distribution. They lived from the Middle Ordovician to the Late Permian, between 470 to 254 million years ago, and were a true terror of the oceans for this period.

Due to their segmented body and specialized front appendages, they are also known as sea scorpions, though the relation to modern scorpions is distant. Even so, many species within the Eurypterid order struck an imposing profile with some developing large claw-like structures.

Sea scorpions are split between two main groups, Eurypterina with their paddle-like appendage on their sixth leg for swimming, and Stylonurina which retained all six pairs of legs for walking.

The swimming Eurypterina were the more active predators, using their mobility to close in on prey, while the walking Stylonurina used different strategies to get a meal. They were bottom feeders, using a sweep-feeding technique to gather up a mass of small prey with their claws to chow down.

Evidence of the diet of a sea scorpion is sparse, so it is unclear exactly what they ate. However, with their large bodies, claw & spine appendages, and stereoscopic vision, scientists are quite certain they were carnivores and dangerous ones at that.

Some sea scorpion species found their way to the top of the food chain, where they reached a massive size as apex predators. The largest genus, Jaekelopterus, topped out at eight feet long, certainly not a creature you'd want to meet at the beach today! Other species were far smaller, with the smallest not even reaching an inch in length.

Freshwater environments were the primary habitat for Eurypterids, though there is evidence that they could venture onto land for some period of time.

Terrestrial fossils are slim, but a well-preserved Adelophthalmus pyrrhae fossil indicates air-breathing organs called Kiemenplatten allowed for extended periods on land. Sea scorpions may even be direct ancestors of today’s arachnids, their descendants abandoning the water entirely in favor of land.