Animal Armageddon
Eurypterids
Super-Sized Sea Scorpions: At the time of Earth's first mass extinction, about 450 million years ago, vicious sea scorpions called eurypterids routinely challenged the nautiloids for the ocean's best feeding grounds. Eurypterids belonged to the same class as spiders, scorpions and horseshoe crabs. The largest eurypterids were 6 to 7 feet in length and weighed about as much as an NFL lineman. Megalograptis, seen above, was about 4 feet long from head to tail.
Fixed for a Fight: The eurypterids' outer shell, or "carapace," protected its soft internal organs from attack by others of its kind, and from fierce predators like the nautiloids. Fossilized eurypterids tend to have prominent scratch marks on their carapaces, indicating that they lived a tough life of constant battle. Like scorpions, the eurypterids' tail ended in a spike. With its tail poised over its head in the typical scorpion pose, a eurypterid would strike at its prey or predator with this spike. Its possible that they were able to inject venom in this manner.
Getting Around: The eurypterids' legs, called "chelicerae," were tough and covered in bristly spines. They had six sets of chelicerae attached to the underside of their "prosoma," or head. The last of these ended in a flattened paddle which the eurypterids used for swimming, moving around on the sea bottom and (eventually) walking on land.
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As seen in ANIMAL ARMAGEDDON:"
Episode 1 — "Death Rays
 Watch a Video of Eurypterids.
COULD YOU SURVIVE? Take the "Staying Afloat in the Age of Sea Creatures" Quiz to find out.
Eurypterids: CUTE or CREEPY? Rate their fright factor in Prehistoric Scary or Not?
Is an ancient sea scorpion the largest bug ever to live on Earth? Meet the enormous pterygotid eurypterid at HowStuffWorks.com. |
NEXT CREATURE: Straight-Shelled Nautiloid »
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