A fearsome fossil claw discovered in Germany belonged to the biggest bug ever known, the size of a large crocodile,
the 390-million-year-old sea scorpion was the top predator of its day, slicing up fish and cannibalizing its own kind in coastal swamp waters, fossil experts say.
Jaekelopterus rhenaniae measured some 8.2 feet (2.5 meters) long, scientists estimate, based on the length of its 18-inch (46-centimeter), spiked claw.
The find shows that arthropods—animals such as insects, spiders, and crabs, which have hard external skeletons, jointed limbs, and segmented bodies—once grew much larger than previously thought, said paleobiologist Simon Braddy of the University of Bristol in the United Kingdom.
"This is an amazing discovery," Braddy said.
"We have known for some time that the fossil record yields monster millipedes, supersized scorpions, colossal cockroaches, and jumbo dragonflies," he added. "But we never realized, until now, just how big some of these ancient creepy-crawlies were."
The newfound fossil creature is estimated to be at least one and a half feet (46 centimeters) longer than any previously known prehistoric sea scorpion, a group called eurypterids.
Braddy and co-author Markus Poschmann of the Mainz Museum in Germany report the find in the latest issue of the journal Biology Letters.
Poschmann uncovered the fossilized claw in a quarry near Prüm in Germany.
Rock layers encasing it suggest the creature lived in a brackish coastal swamp or river delta, the researchers said.