Human-Sized Sea Scorpion: What Scientists Learned From the Fossil

If you think scorpions are scary now, wait until you get a look at their human-sized prehistoric cousins.

The Pentecopterus, named after a Greek warship that resembles the outline of the species, was a fearsome predator that lurked in the sea 460 million years ago, according to a study published on Monday in the journal BMC Evolutionary Biology.

The scary predator had a long head with a narrow body and several pairs of limbs that were likely used to swim, dig and snare its prey, according to the study.

The surprisingly well-preserved fossil, which included 150 fragments, was excavated from a fossil bed in the Upper Iowa River.

"Perhaps most surprising is the fantastic way it is preserved -- the exoskeleton is compressed on the rock but can be peeled off and studied under a microscope," James Lamsdell, the lead author of the study at Yale University, said in a statement. "This shows an amazing amount of detail, such as the patterns of small hairs on the legs. At times it seems like you are studying the shed skin of a modern animal - an incredibly exciting opportunity for any paleontologist."

The finding is significant for paleontologists since the sea scorpion is believed to be at least 10 million years older than previous members of its eurypterid group that have been discovered, along with the largest known to have existed.