Ancient sea scorpions dispatched prey with serrated tail

April 18 (UPI) -- Before sharks and giant squids came to haunt the ocean depths, a different kind of predator reigned supreme -- sea scorpions. New research suggests sea scorpions, or eurypterids, likely used their swiveling, serrated tail to kill their prey.

An exceptionally well preserved fossil specimen of the eurypterid species Slimonia acuminata revealed an articulated spine and tail curved markedly to one side. The tail is tipped by a sharp, serrated spine resembling the head of a nib pen.

Analysis of the tail suggests it was unable to flex vertically like the tail of a lobster, but could move horizontally from side-to-side, enabling a whip-like strike.

"Our study suggests that sea scorpions used their tails, weaponized by their serrated spiny tips, to dispatch their prey," lead study author Scott Persons, a paleontologist at the University of Alberta, said in a news release.

The sea scorpion fossil was recovered from Scotland's Patrick Burn Formation, a geologic formation featuring fossils from the Silurian period, between 444 and 419 million years ago. Researchers described the new fossil and its scientific implications in the journal American Naturalist.