British and German scientists reported the discovery of giant fossilised claw from an ancient sea scorpion. Nothing unusual so far, but the claw is 46 centimetres long, which means that its owner, a sea scorpion (eurypterid) Jaekelopterus rhenaniae, it measured somewhere around 2 – 2,5 meters, almost half a meter longer than previous estimates for these arthropods and the largest one ever to have evolved.

According to the scientists Jaekelopterus rhenaniae lived between 460 and 255 million years ago.

A phylogenetic analysis of the pterygotid clade revealed that Jaekelopterus is sister-taxon to the genus Acutiramus, and is among the most derived members of the pterygotids, in contrast to earlier suggestions.

Eurypterids are believed to be the extinct aquatic ancestors of scorpions and possibly all arachnids.

The claw was discovered by Markus Poschmann, the co-author of the research published the Royal Society’s journal Biology Letters.

Dr Simon Braddy from the Department of Earth Sciences at the University of Bristol, co-author of an article about the find, explained why this discovery is important.

“We have known for some time that the fossil record yields monster millipedes, super-sized scorpions, colossal cockroaches, and jumbo dragonflies, but we never realized, until now, just how big some of these ancient creepy-crawlies were”, Braddy said in a press statement.

Though, there is no explanation about how those creatures could grow into such amazing size.

While some researchers believe that giant arthropods evolved due to higher levels of oxygen in the atmosphere in the past, Braddy underlined there are many other factors involved.

“It is more likely that some ancient arthropods were big because there was little competition from the vertebrates, as we see today. If the amount of oxygen in the atmosphere suddenly increased, it doesn't mean all the bugs would get bigger,” he said.

Photo Credit: Simon Powell, University of Bristol